Name: biomechanical testing of murine tendons
Uploaded: 2019-10-15T14:30:00
Description: Watch this Scientific Journal Video about Biomechanical Testing of Murine Tendons at JoVE.com

Studien ble støttet av NIH/NIAMS (R01 AR055580, R01 AR057836).

Dyrestudier ble godkjent av Columbia University institusjonelle Animal Care og use Committee. Mus som brukes i denne studien var av en C57BL/6J bakgrunn og ble kjøpt fra The Jackson Laboratory (bar Harbor, ME, USA). De ble plassert i patogen-fri barriere forhold og ble gitt mat og vann ad lib.
1. utvikling av tilpasset-Fit 3D trykte inventar for gripende bein
<ol><li>Bone image oppkjøp og 3D-bein modell konstruksjon<ol><li>Analysere bein av interesse i forberedelsene til 3D modell opprette...

<ol>
	<li>Girish, N., Ramachandra, K., Arun, G. M., Asha, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prevalence+of+Musculoskeletal+Disorders+Among+Cashew+Factory+Workers.">Prevalence of Musculoskeletal Disorders Among Cashew Factory Workers.</a> Archives of Environmental &amp; Occupational Health. 67, 37-42 (2012).</li><li>Thomopoulos, S., Parks, W. C., Rifkin, D. B., Derwin, K. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanisms+of+tendon+injury+and+repair.">Mechanisms of tendon injury and repair.</a> Journal of Orthopaedic Research. 33, 832-839 (2016).</li><li>Scott, A., Ashe, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Common+Tendinopathies+in+the+Upper+and+Lower+Extremities.">Common Tendinopathies in the Upper and Lower Extremities.</a> Current Sports Medicine Reports. 5, 233-241 (2006).</li><li>Praemer, A., Furner, S., Rice, D. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Musculoskeletal+Conditions+in+the+United+States.">Musculoskeletal Conditions in the United States.</a> American Academy of Orthopaedic Surgeons. , (1992).</li><li>Nourissat, G., Berenbaum, F., Duprez, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tendon+injury:+From+biology+to+tendon+repair.">Tendon injury: From biology to tendon repair.</a> Nature Reviews Rheumatology. 11, 223-233 (2015).</li><li>Galatz, L. M., Ball, C. M., Teefey, S. A., Middleton, W. D., Yamaguchi, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+outcome+and+repair+integrity+of+completely+arthroscopically+repaired+large+and+massive+rotator+cuff+tears.">The outcome and repair integrity of completely arthroscopically repaired large and massive rotator cuff tears.</a> The Journal of Bone and Joint Surgery. 86, 219-224 (2004).</li><li>Sher, J. S., Uribe, J. W., Posada, A., Murphy, B. J., Zlatkin, M. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Abnormal+findings+on+magnetic+resonance+images+of+asymptomatic+shoulders.">Abnormal findings on magnetic resonance images of asymptomatic shoulders.</a> The Journal of Bone and Joint Surgery. 77, 10-15 (1995).</li><li>Ker, R. F., Wang, X. T., Pike, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fatigue+quality+of+mammalian+tendons.">Fatigue quality of mammalian tendons.</a> The Journal of Experimental Biology. 203, 1317-1327 (2000).</li><li>Wilson, J. J., Best, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Common+overuse+tendon+problems:+A+review+and+recommendations+for+treatment.">Common overuse tendon problems: A review and recommendations for treatment.</a> American Family Physician. 72, 811-818 (2005).</li><li>Fleischer, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biomechanical+strength+and+failure+mechanism+of+different+tubercula+refixation+methods+within+the+framework+of+an+arthroplasty+for+shoulder+fracture.">Biomechanical strength and failure mechanism of different tubercula refixation methods within the framework of an arthroplasty for shoulder fracture.</a> Orthopaedics &amp; Traumatology: Surgery &amp; Research. 103, 165-169 (2017).</li><li>West, J. R., Juncosa, N., Galloway, M. T., Boivin, G. P., Butler, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+in+vivo+Achilles+tendon+forces+in+rabbits+during+treadmill+locomotion+at+varying+speeds+and+inclinations.">Characterization of in vivo Achilles tendon forces in rabbits during treadmill locomotion at varying speeds and inclinations.</a> Journal of Biomechanics. 37, 1647-1653 (2004).</li><li>Cavinatto, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+versus+late+repair+of+rotator+cuff+tears+in+rats.">Early versus late repair of rotator cuff tears in rats.</a> Journal of Shoulder and Elbow Surgery. 27, 606-613 (2018).</li><li>Potter, R., Havlioglu, N., Thomopoulos, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+developing+shoulder+has+a+limited+capacity+to+recover+after+a+short+duration+of+neonatal+paralysis.">The developing shoulder has a limited capacity to recover after a short duration of neonatal paralysis.</a> Journal of Biomechanics. 47, 2314-2320 (2014).</li><li>Connizzo, B. K., Sarver, J. J., Iozzo, R. V., Birk, D. E., Soslowsky, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+Age+and+Proteoglycan+Deficiency+on+Collagen+Fiber+Re-Alignment+and+Mechanical+Properties+in+Mouse+Supraspinatus+Tendon.">Effect of Age and Proteoglycan Deficiency on Collagen Fiber Re-Alignment and Mechanical Properties in Mouse Supraspinatus Tendon.</a> Journal of Biomechanical Engineering. 135, 021019 (2013).</li><li>Beason, D. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypercholesterolemia+increases+supraspinatus+tendon+stiffness+and+elastic+modulus+across+multiple+species.">Hypercholesterolemia increases supraspinatus tendon stiffness and elastic modulus across multiple species.</a> Journal of Shoulder and Elbow Surgery. 22, 681-686 (2013).</li><li>Miller, K. S., Connizzo, B. K., Soslowsky, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Collagen+fiber+re-alignment+in+a+neonatal+developmental+mouse+supraspinatus+tendon+model.">Collagen fiber re-alignment in a neonatal developmental mouse supraspinatus tendon model.</a> Annals of Biomedical Engineering. 40, 1102-1110 (2012).</li><li>Cong, G. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluating+the+role+of+subacromial+impingement+in+rotator+cuff+tendinopathy:+Development+and+analysis+of+a+novel+murine+model.">Evaluating the role of subacromial impingement in rotator cuff tendinopathy: Development and analysis of a novel murine model.</a> Journal of Orthopaedic Research. 36, 2780-2788 (2018).</li><li>Thomopoulos, S., Birman, V., Genin, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+Interfaces+and+Attachments+in+Biology.">Structural Interfaces and Attachments in Biology.</a> Infection and Immunity. 35, (2013).</li><li>Boivin, G. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biomechanical+properties+and+histology+of+db/db+diabetic+mouse+Achilles+tendon.">Biomechanical properties and histology of db/db diabetic mouse Achilles tendon.</a> Muscles, Ligaments and Tendons Journal. 4, 280-284 (2014).</li><li>Ansorge, H. L., Adams, S., Birk, D. E., Soslowsky, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical,+Compositional,+and+Structural+Properties+of+the+Post-natal+Mouse+Achilles+Tendon.">Mechanical, Compositional, and Structural Properties of the Post-natal Mouse Achilles Tendon.</a> Annals of Biomedical Engineering. 39, 1904-1913 (2011).</li><li>Shu, C. C., Smith, M. M., Appleyard, R. C., Little, C. B., Melrose, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Achilles+and+tail+tendons+of+perlecan+exon+3+null+heparan+sulphate+deficient+mice+display+surprising+improvement+in+tendon+tensile+properties+and+altered+collagen+fibril+organisation+compared+to+C57BL/6+wild+type+mice.">Achilles and tail tendons of perlecan exon 3 null heparan sulphate deficient mice display surprising improvement in tendon tensile properties and altered collagen fibril organisation compared to C57BL/6 wild type mice.</a> PeerJ. 6, 5120 (2018).</li><li>Probst, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+clamping+technique+for+biomechanical+testing+of+tendons+in+small+animals.">A new clamping technique for biomechanical testing of tendons in small animals.</a> Journal of Investigative Surgery. 13, 313-318 (2000).</li><li>Talan, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Body+temperature+of+C57BL/6J+mice+with+age.">Body temperature of C57BL/6J mice with age.</a> Experimental Gerontology. 19, 25-29 (1984).</li><li>Newton, M. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+influence+of+testing+angle+on+the+biomechanical+properties+of+the+rat+supraspinatus+tendon.">The influence of testing angle on the biomechanical properties of the rat supraspinatus tendon.</a> Journal of Biomechanics. 49, 4159-4163 (2016).</li><li>Schwartz, A. G., Lipner, J. H., Pasteris, J. D., Genin, G. M., Thomopoulos, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Muscle+loading+is+necessary+for+the+formation+of+a+functional+tendon+enthesis.">Muscle loading is necessary for the formation of a functional tendon enthesis.</a> Bone. 55, 44-51 (2014).</li><li>Gimbel, J. A., Van Kleunen, J. P., Williams, G. R., Thomopoulos, S., Soslowsky, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long+durations+of+immobilization+in+the+rat+result+in+enhanced+mechanical+properties+of+the+healing+supraspinatus+tendon.">Long durations of immobilization in the rat result in enhanced mechanical properties of the healing supraspinatus tendon.</a> Journal of Biomechanical Engineering. 129, 400-404 (2006).</li><li>Freedman, B. R., Sarver, J. J., Buckley, M. R., Voleti, P. B., Soslowsky, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biomechanical+and+structural+response+of+healing+Achilles+tendon+to+fatigue+loading+following+acute+injury.">Biomechanical and structural response of healing Achilles tendon to fatigue loading following acute injury.</a> Journal of Biomechanics. 47, 2028-2034 (2014).</li><li>Deymier, A. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+multiscale+structural+and+mechanical+effects+of+mouse+supraspinatus+muscle+unloading+on+the+mature+enthesis.">The multiscale structural and mechanical effects of mouse supraspinatus muscle unloading on the mature enthesis.</a> Acta Biomaterialia. 83, 302-313 (2019).</li><li>Killian, M. L., Thomopoulos, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Scleraxis+is+required+for+the+development+of+a+functional+tendon+enthesis.">Scleraxis is required for the development of a functional tendon enthesis.</a> FASEB Journal. 30, 301-311 (2016).</li><li>Schwartz, A. G., Long, F., Thomopoulos, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enthesis+fibrocartilage+cells+originate+from+a+population+of+Hedgehog-responsive+cells+modulated+by+the+loading+environment.">Enthesis fibrocartilage cells originate from a population of Hedgehog-responsive cells modulated by the loading environment.</a> Development. 142, 196-206 (2015).</li><li>Bell, R., Taub, P., Cagle, P., Flatow, E. L., Andarawis-Puri, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+mouse+model+of+supraspinatus+tendon+insertion+site+healing.">Development of a mouse model of supraspinatus tendon insertion site healing.</a> Journal of Orthopaedic Research. 33, 25-32 (2014).</li><li>Connizzo, B. K., Bhatt, P. R., Liechty, K. W., Soslowsky, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diabetes+Alters+Mechanical+Properties+and+Collagen+Fiber+Re-Alignment+in+Multiple+Mouse+Tendons.">Diabetes Alters Mechanical Properties and Collagen Fiber Re-Alignment in Multiple Mouse Tendons.</a> Annals of Biomedical Engineering. 42, 1880-1888 (2014).</li><li>Eekhoff, J. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functionally+Distinct+Tendons+From+Elastin+Haploinsufficient+Mice+Exhibit+Mild+Stiffening+and+Tendon-Specific+Structural+Alteration.">Functionally Distinct Tendons From Elastin Haploinsufficient Mice Exhibit Mild Stiffening and Tendon-Specific Structural Alteration.</a> Journal of Biomechanical Engineering. 139, 111003 (2017).</li><li>Mikic, B., Bierwert, L., Tsou, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Achilles+tendon+characterization+in+GDF-7+deficient+mice.">Achilles tendon characterization in GDF-7 deficient mice.</a> Journal of Orthopaedic Research. 24, 831-841 (2006).</li><li>Sikes, K. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Knockout+of+hyaluronan+synthase+1,+but+not+3,+impairs+formation+of+the+retrocalcaneal+bursa.">Knockout of hyaluronan synthase 1, but not 3, impairs formation of the retrocalcaneal bursa.</a> Journal of Orthopaedic Research. 36, 2622-2632 (2018).</li><li>Wang, V. M., Banack, T. M., Tsai, C. W., Flatow, E. L., Jepsen, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Variability+in+tendon+and+knee+joint+biomechanics+among+inbred+mouse+strains.">Variability in tendon and knee joint biomechanics among inbred mouse strains.</a> Journal of Orthopaedic Research. 24, 1200-1207 (2006).</li><li>Wang, V. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Murine+tendon+function+is+adversely+affected+by+aggrecan+accumulation+due+to+the+knockout+of+ADAMTS5.">Murine tendon function is adversely affected by aggrecan accumulation due to the knockout of ADAMTS5.</a> Journal of Orthopaedic Research. 30, 620-626 (2011).</li><li>Zhang, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tendon+mineralization+is+progressive+and+associated+with+deterioration+of+tendon+biomechanical+properties,+and+requires+BMP-Smad+signaling+in+the+mouse+Achilles+tendon+injury+model.">Tendon mineralization is progressive and associated with deterioration of tendon biomechanical properties, and requires BMP-Smad signaling in the mouse Achilles tendon injury model.</a> Matrix Biology. 52-54, 315-324 (2016).</li><li>Rooney, S. I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ibuprofen+differentially+affects+supraspinatus+muscle+and+tendon+adaptations+to+exercise+in+a+rat+model.">Ibuprofen differentially affects supraspinatus muscle and tendon adaptations to exercise in a rat model.</a> American Journal of Sports Medicine. 44, 2237-2245 (2016).</li><li>Galasso, O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quality+of+Life+and+Functional+Results+of+Arthroscopic+Partial+Repair+of+Irreparable+Rotator+Cuff+Tears.">Quality of Life and Functional Results of Arthroscopic Partial Repair of Irreparable Rotator Cuff Tears.</a> Arthroscopy - Journal of Arthroscopic and Related Surgery. 33, 261-268 (2017).</li><li>Sarver, D. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sex+differences+in+tendon+structure+and+function.">Sex differences in tendon structure and function.</a> Journal of Orthopaedic Research. 35, 2117-2126 (2017).</li><li>Razmjou, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Disability+and+satisfaction+after+Rotator+Cuff+decompression+or+repair:+A+sex+and+gender+analysis.">Disability and satisfaction after Rotator Cuff decompression or repair: A sex and gender analysis.</a> BMC Musculoskeletal Disorders. 12, 66 (2011).</li></ol>

Murine dyremodeller er ofte brukt til å studere sene lidelser, men karakterisering av deres mekaniske egenskaper er utfordrende og uvanlig i litteraturen. Formålet med denne protokollen er å beskrive en tid effektiv og reproduserbar metode for strekk testing av murine sener. Den nye metoder reduserte tiden det tar å teste en prøve fra timer til minutter og eliminert en stor gripende gjenstand som var et vanlig problem i tidligere metoder.
Flere trinn beskrevet i denne protokollen er avgj?...

Sene lidelser er vanlig og svært utbredt blant de aldrende, atletisk og aktive populasjoner1,2,3. I USA, 16 400 000 bindevevs skader rapporteres hvert år4 og står for 30% av all skade-relaterte legekontor besøk3,5,6,7, 8i den. De hyppigst rammede områdene inkluderer Rotator cuff, Achilles sene, og patellar sene9. Selv om en rekke ikke-operative og operative behandlinger har blitt utforsket, inkludert antiinflammatoriske legemidler, rehabilitering, og kirurgisk reparasjon, utfall forblir fattige, med begrenset avkastning til funksjon og høy forekomst av svikt5, 6i den. Disse dårlige kliniske utfall har motivert grunnleggende og translational studier som søker å forstå tendinopati og å utvikle romanen behandling tilnærminger.
Strekk biomekaniske egenskaper er de primære kvantitative utfall definere sene funksjon. Derfor, laboratorie karakterisering av tendinopati og behandling effekt må inneholde en streng testing av sene strekk egenskaper. Tallrike studier har beskrevet metoder for å bestemme biomekaniske egenskaper av sener fra dyremodeller som rotter, sauer, hunder og kaniner10,11,12. Imidlertid har få studier testet biomekaniske egenskapene til murine sener, hovedsakelig på grunn av vanskeligheter med å gripe den lille vev for strekk testing. Som murine modeller har en rekke fordeler for mechanistically studere tendinopati, inkludert genetisk manipulasjon, omfattende reagens alternativer, og lave kostnader, utvikling av nøyaktige og effektive metoder for å biomekanisk teste murine vev er nødvendig.
For å kunne teste de mekaniske egenskapene til sener, må vevet bli grepet effektivt, uten å skli eller artifactual rive i grepet grensesnittet eller oppsprekking av veksten plate. I mange tilfeller, spesielt for korte sener, benet er grepet på den ene enden og senen er grepet i den andre enden. Bein er vanligvis sikret ved å bygge dem inn i materialer som epoxy harpiks13 og polymetalmetakrylat14,15. Sener er ofte plassert mellom to lag med sandpapir, limt med Cyanoacrylate, og sikret ved hjelp av kompresjon klemmer (hvis tverrsnitt er flat) eller i et frosset medium (hvis tverrsnitt er stor)15,16,17 . Disse metodene har blitt brukt til biomekanisk test murine sener, men utfordringene oppstår på grunn av den lille størrelsen på prøvene og etterlevelse av veksten plate, som aldri ossifies18. For eksempel er diameteren på murine ledd hode bare noen få millimeter, og dermed gjør gripende av benet vanskelig. Nærmere bestemt, strekk testing av murine supraspinatus sene-til-bein prøver ofte resulterer i svikt i vekst plate i stedet for i senen eller ved sene enthesis. Tilsvarende er biomekaniske testing av Achilles sene utfordrende. Selv om Achilles sene er større enn andre murine sener, er calcaneus liten, noe som gjør gripende av dette benet vanskelig. Benet kan fjernes, etterfulgt av gripende de to sene endene; men dette utelukker testing av sene-til-bein vedlegg. Andre grupper rapport gripende calcaneus benet ved hjelp av skreddersydde inventar19,20, forankring av klemmer21, festing i selv herding plast sement22 eller ved hjelp av en konisk form slot22, men disse tidligere metoder fortsatt begrenset av lav reproduserbarhet, høy gripe svikt priser, og kjedelige forberedelser krav.
Målet med den nåværende studien var å utvikle en nøyaktig og effektiv metode for strekk biomekaniske testing av murine sener, med fokus på supraspinatus og Achilles sener som eksempler. Ved hjelp av en kombinasjon av 3D-rekonstruksjoner fra opprinnelig bein anatomi, solid modellering og additiv produksjon, ble en ny metode utviklet for å gripe inn i beina. Disse inventar effektivt sikret bein, hindret vekst plate svikt, redusert prøveforberedelse tid, og økt testing reproduserbarhet. Den nye metoden er lett å tilpasse for å teste andre murine sener samt sener i rotter og andre dyr.

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			<td >Agarose</td>
			<td >Fisher Scientific</td>
			<td >BP160-100</td>
			<td >Dissovle 1g in 100 ml ultrapure water to make 1% agarose&#160;</td>
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			<td >Bruker microCT&#160;</td>
			<td >Bruker BioSpin Corp</td>
			<td >Skyscan 1272&#160;</td>
			<td>Used by authors</td>
		</tr>
		<tr >
			<td >ElectroForce&#160;</td>
			<td >TA Instruments</td>
			<td >3200</td>
			<td>Testing platform</td>
		</tr>
		<tr >
			<td >Ethanol 200 Proof</td>
			<td >Fisher Scientific</td>
			<td >A4094</td>
			<td>Dilute to 70% and use as suggested in protocol</td>
		</tr>
		<tr >
			<td >Fixture to attach grips</td>
			<td >Custom made</td>
			<td ></td>
			<td>Used by authors</td>
		</tr>
		<tr >
			<td >Kimwipes</td>
			<td >Kimberly-Clark</td>
			<td >&#160;S-8115</td>
			<td>As suggested in protocol</td>
		</tr>
		<tr >
			<td >MicroCT CT-Analyser (Ctan)</td>
			<td >Bruker BioSpin Corp</td>
			<td ></td>
			<td>Used by authors for visualizing and analyzing micro-CT scans&#160;</td>
		</tr>
		<tr >
			<td >MilliQ water (Ultrapure water)</td>
			<td>Millipore Sigma</td>
			<td>QGARD00R1 (or related purifier)</td>
			<td>100 ml&#160;</td>
		</tr>
		<tr >
			<td >Meshmixer</td>
			<td >Autodesk</td>
			<td >http://www.meshmixer.com/</td>
			<td >Free engineering software used by authors to refine mesh</td>
		</tr>
		<tr >
			<td >Objet EDEN 260VS&#160;</td>
			<td >Stratasys LTD</td>
			<td ></td>
			<td>Precision Prototyping</td>
		</tr>
		<tr >
			<td >Objet Studio</td>
			<td >Stratasys LTD</td>
			<td ></td>
			<td>Used by authors with 3D printer</td>
		</tr>
		<tr >
			<td >PBS - Phosphate-Buffered Saline</td>
			<td >ThermoFisher Scientific</td>
			<td >10010031</td>
			<td >2.5 L of 10% PBS&#160;</td>
		</tr>
		<tr >
			<td >S&#38;T Forceps</td>
			<td >Fine Science Tools</td>
			<td >00108-11</td>
			<td>Used by authors</td>
		</tr>
		<tr >
			<td >Scalpel Blade - #11</td>
			<td >Fine Science Tools</td>
			<td >10011-00</td>
			<td>Used by authors</td>
		</tr>
		<tr >
			<td >Scalpel Handle - #3</td>
			<td >Fine Science Tools</td>
			<td >10003-12</td>
			<td>Used by authors</td>
		</tr>
		<tr >
			<td >SkyScan 1272</td>
			<td >Bruker BioSpin Corp</td>
			<td ></td>
			<td>Used by authors for visualizing and analyzing micro-CT scans&#160;</td>
		</tr>
		<tr >
			<td >Skyscan CT-Vox</td>
			<td >Bruker BioSpin Corp</td>
			<td ></td>
			<td>Used by authors for visualizing and analyzing micro-CT scans&#160;</td>
		</tr>
		<tr >
			<td >SkyScan NRecon</td>
			<td >Bruker BioSpin Corp</td>
			<td ></td>
			<td>Used by authors for visualizing and analyzing micro-CT scans&#160;</td>
		</tr>
		<tr >
			<td >SolidWorks CAD</td>
			<td >Dassault Syst&#232;mes</td>
			<td >SolidWorks Research Subsription</td>
			<td>Solid modeling computer-aided design used by authors</td>
		</tr>
		<tr >
			<td >SuperGlue</td>
			<td >Loctite</td>
			<td >234790</td>
			<td>As suggested in protocol</td>
		</tr>
		<tr >
			<td >Testing bath</td>
			<td >Custom made</td>
			<td ></td>
			<td>Used by authors</td>
		</tr>
		<tr >
			<td >Thin film grips&#160;</td>
			<td >Custom made</td>
			<td ></td>
			<td>Used by authors</td>
		</tr>
		<tr >
			<td >VeroWhitePlus</td>
			<td >Stratasys LTD</td>
			<td >NA</td>
			<td>3D printing material used by authors</td>
		</tr>
		<tr >
			<td >WinTest&#160;</td>
			<td >WinTest Software</td>
			<td ></td>
			<td>Used by authors to collect data</td>
		</tr>
	</tbody>
</table>

biomechanical testing of murine tendons

Sene lidelser er vanlig, påvirker folk i alle aldre, og er ofte ødeleggende. Standard behandlinger, som anti-inflammatoriske legemidler, rehabilitering, og kirurgisk reparasjon, ofte mislykkes. For å definere sene funksjon og demonstrere effekten av nye behandlinger, de mekaniske egenskapene til sener fra dyremodeller må være nøyaktig bestemmes. Murine dyremodeller er nå mye brukt til å studere sene lidelser og evaluere romanen behandlinger for tendinopathies; men å bestemme de mekaniske egenskapene til mus sener har vært utfordrende. I denne studien, et nytt system ble utviklet for sene mekanisk testing som inkluderer 3D-trykt inventar som nøyaktig samsvarer med anatomi av humerus og calcaneus til mekanisk test supraspinatus sener og Achilles sener, henholdsvis. Disse inventar ble utviklet ved hjelp av 3D rekonstruksjoner av innfødte bein anatomi, solid modellering, og additiv produksjon. Den nye tilnærmingen eliminert artifactual gripende svikt (f. eks svikt ved vekst plate svikt snarere enn i senen), redusert total testing tid, og økt reproduserbarhet. Videre er denne nye metoden lett å tilpasse for å teste andre murine sener og sener fra andre dyr.

3D-trykte inventar ble brukt til å teste 8-ukers gamle murine supraspinatus og Achilles sener. Alle mekaniske prøver mislyktes på enthesis, som kjennetegnes ved microCT-skanninger, visuell inspeksjon og video analyse etter strekk prøver. En en-til-en sammenligning av tidligere og nåværende metoder for supraspinatus sene testing i vårt laboratorium er vist i Figur 3. I forrige metode28,29,30, ...

Watch this Scientific Journal Video about Biomechanical Testing of Murine Tendons at JoVE.com

Biomechanical Testing of Murine Tendons

Protokollen beskriver effektiv og reproduserbar strekk biomekaniske testmetoder for murine sener gjennom bruk av tilpasset-Fit 3D trykt inventar.

Biomekaniske testing av murine sener

Tendon disorders are common, affect people of all ages, and are often debilitating. Standard treatments, such as anti-inflammatory drugs, rehabilitation, ...

Protokollen beskriver en effektiv og reproduserbar metode for biomekanisk testing av musesene gjennom gjenbrukbare tilpassede 3D-trykte inventar. De nye metodene reduserer tiden det tar å teste prøven fra timer til minutter og eliminere en stor gripende artefakt som var et vanlig problem i tidligere metoder. Denne metoden er ikke begrenset til supraspinatus og Achilles sener.Det kan lett tilpasses til å teste andre musesene og sener fra større dyr. For å sikre reproduserbarhet og effektivitet av tilnærmingen, kan det være nødvendig med flere sykluser med designprototyping og validering for inventar som ikke er beskrevet her. Til å begynne med, utfør en mikrokomputert tomografiskanning av hele beinet i agarosegelen.Etter rekonstruksjon i tverrsnittsbilder, velger du kommandoen Fil åpen for å åpne fildatasettet. Åpne innstillinger for dialogfilen, og velg kategorien Avansert. Bruk den adaptive gjengivelsesalgoritmen til å konstruere 3D-modellene som gir jevnere overflatedetaljer.Bruk 10 som lokalitetsparameter som definerer avstanden i piksler til nabopunktet som brukes til å finne objektkantlinjen. Minimer toleransen til 0,1 for å redusere filstørrelsen. Hvis du vil angi interessevolumet, velger du manuelt to bilder som skal angis som toppen og bunnen av det valgte VOI-området, og deretter går du til den andre siden, Interesseområde.Velg interesseområdet manuelt på ett enkelt tverrsnittsbilde. Gjenta valg av roi for hvert 10 til 15 tverrsnittsbilder. Deretter går du til den tredje siden, Binært utvalg.Klikk Fra datasett på Histogram-menyen for å vise histogrammets fordeling av lysstyrke fra alle bilder av datasettet. Klikk også på Opprett en 3D-modellfil-menyen på Histogram-menyen. Lagre en 3D-modell av beinet i STL-filformat.I Meshmixer-programvaren importerer du mesh og velger Alle som skal redigeres. Velg Produser fra redigering av verktøysett, og velg deretter Trekantbudsjett fra verktøysettet Reduser mål. Reduser tricount og godta endringer.Lagre den nylig reduserte filen i STL-format ved å velge Eksporter As.To designe en supraspinatus sene humeral bein, bruke en solid-modellering dataassistert design program for å lage en tilpasset modell av humerus-gripende ligaen. Åpne STL formatfilen til humerus bein i en solid-modellering program og lagre som en del fil i SLDPRT format. Åpne deretter delfilen for å manuelt opprette tre anatomisk relevante plan, for eksempel sagittal, koronar og tverrgående.Klikk på Fil ny for å opprette den solide blokkkomponentdelen. Klikk på Fil ny for å lage en monteringsmodell med to komponenter, den faste blokken og enten høyre eller venstre humerus bein. Definer retningen på beinet i blokken for å sikre at vinkelen mellom senen og beinet skal være 180 grader.Pass på at hele beinvolumet passer inn i blokken. Velg blokken i Samling-vinduet, og klikk på Rediger komponent fra samlingsverktøylinjen. Klikk Sett inn, Funksjoner, Hulrom.Velg Ensartet skalering, og angi 0 %som verdien som skaleres i alle retninger. Undertrykk beindelen og lagre forsamlingen som en del. Åpne sylinderen med hulromsdel.Lag en skisse, sørg for å bare la 0,5 millimeter over humeralhodet. Velg Ekstrudert kutt fra Funksjoner. Klipp forsamlingen langs sagittalplanet for å lage to symmetriske komponenter som passer til beinet fremre og bakre.Klipp monteringsdelen langs sagittalplanet for å lage to symmetriske komponenter som passer beinet fremre og bakre. Det er viktig å sikre humeral hodet for å hindre vekstplate svikt og å definere en tett klaring som unngår disengaging av humerus fra modellen under testing. Fortsett som beskrevet i manuskriptet for å fullføre den bakre komponenten og fremre komponenten.Lagre begge komponentene som separate delfiler. Trykk nå på Sett inn mønster, Speil, og velg Mirror for å lage 3D-speilmodeller for hver komponent av armaturen for motsatt lem. Velg forsiden som et speil ansikt vanlig.Velg delen som kroppen som skal speiles. Velg speilplanet og lag en skisse som inneholder alt materiale. Fra Funksjoner velger du Ekstrudert kutt for å fjerne den opprinnelige delen og for å beholde bare speildel.Klikk på bunnen av delen og bruk som et fly for å lage en skisse. Klikk på Skissetekst og legg til L eller R.Dette legger til en ets på bunnen av inventar for å skille mellom venstre og høyre side. Lagre alle armaturdeler i STL-standard filformat som forberedelse til 3D-utskrift.For å dissekere supraspinatus muskel-senen, humerus bein prøven, først plassere euthanized musen i en utsatt posisjon og gjøre et snitt i huden fra over albuen av forsag mot skulderen. Bruk tang til å forsiktig fjerne huden med stump disseksjon slik at skulderens muskulatur er synlig. Fjern vevet rundt humerus til beinet er utsatt.Hold humerus med tang og fjern forsiktig deltoid- og trapeziusmusklene for å eksponere den coracoacromialbuen. Identifiser ac-skjøten og skill forsiktig kragebenet fra acromion med et skalpellblad. Vær forsiktig så du ikke skader supraspinatus-senen og benete tilbehøret, fjern muskelen fra scapulartilbehøret ved hjelp av et skalpellblad.Løsne humeral hodet fra glenoid og lacerate felles kapsel og infraspinatus subcapularis og teres mindre sener. Disarticulate albueleddet for å skille humerus fra ulna og radius. Isoler humerus-supraspinatus sene muskelprøven og rengjør overflødig mykt vev på humerus og humeral hodet.For å dissekere akillessenen, calcaneus-beinet, plasser en eutanisert mus i en utsatt posisjon. Ta vare på ikke å skade akillessenen og dens benete vedlegg, fjern huden med sløv disseksjon slik at muskulaturen rundt ankelen og kneleddene blir utsatt. Bruk et skalpellblad, som starter ved Achilles sene-calcaneus vedlegg, forsiktig løsne gastrocnemius muskelen fra sine proksimale vedlegg.Forsiktig disarticulate calcaneus fra de ulike tilstøtende bein og isolere Achilles sene-calcaneus prøven og rense av overflødig bløtvev. For å bestemme tverrsnittsområdet av senen, sett beinet opp ned for å suspendere prøven i kryorøret fylt med agarosegel med beinet i agarosegelen og senen og muskelen utenfor. Etter skanningen ved hjelp av mikrokomputert tomografi, fjern forsiktig muskelen fra senen ved hjelp av et skalpellblad.Sett beinet inn i 3D-trykt armatur og fest dem til testgitteret. Sett inn og lim senen mellom et brettet tynt vevpapir og klem det ved hjelp av tynne filmgrep. Sett prøven og håndtakene inn i et testbad på PBS ved 37 grader Celsius og utfør en mekanisk test.I denne studien, ved hjelp av gjenbrukbare 3D-trykte inventar for å gripe bein, ble prøveforberedelsestiden redusert fra timer til minutter. Representative lastdeformasjonskurver for strekktesting av supraspinatus sene ved hjelp av gjeldende metoder eliminert store gripende artefakt som vekstplate svikt. De mekaniske egenskapene til supraspinatus og akillessener viser en betydelig effekt av sex basert på unpaired T-tester med P-verdi mindre enn 0,05.Micro CT målte vellykket tverrsnittsområdet langs lengden av supraspinatus sene langs lengden av Akillessenen. Det er viktig å huske at hvert anatomiske nettsted har spesifikke designkriterier som er nødvendige for effektiv gripende. Derfor bør utformingen for hvert armatur tilpasses tilsvarende.I tillegg til strekktesting til feil, kan disse inventar brukes til sykliske lasting tester, som gir informasjon om sene tretthet og viskoelastiske egenskaper. Karakterisere de mekaniske egenskapene til murin sener er uvanlig i litteraturen på grunn av en rekke grunner, inkludert vanskeligheten med å gripe disse små vev, kjedelige og tidkrevende prøveforberedelsesmetoder og vekstplatefrakturer. Denne protokollen presenterer en tidseffektiv og reproduserbar metode for testing av musesene som har eliminert artefaktgrepsfeil og har tredoblet antall prøver som kan testes på en dag.

Research

JoVE Journal

Bioengineering

Directed Cellular Self-Assembly to Fabricate Cell-Derived Tissue Rings for Biomechanical Analysis and Tissue Engineering

Each year, hundreds of thousands of patients undergo coronary artery bypass surgery in the United States.1 Approximately one third of these patients do not have suitable autologous donor vessels due to disease progression or previous harvest. The aim of vascular tissue engineering is to develop a suitable alternative source for these bypass grafts. In addition, engineered vascular tissue may prove valuable as living vascular models to study cardiovascular diseases. Several promising approaches to engineering blood vessels have been explored, with many recent studies focusing on development and analysis of cell-based methods.2-5 Herein, we present a method to rapidly self-assemble cells into 3D tissue rings that can be used in vitro to model vascular tissues.
To do this, suspensions of smooth muscle cells are seeded into round-bottomed annular agarose wells. The non-adhesive properties of the agarose allow the cells to settle, aggregate and contract around a post at the center of the well to form a cohesive tissue ring.6,7 These rings can be cultured for several days prior to harvesting for mechanical, physiological, biochemical, or histological analysis. We have shown that these cell-derived tissue rings yield at 100-500 kPa ultimate tensile strength8 which exceeds the value reported for other tissue engineered vascular constructs cultured for similar durations (&lt;30 kPa).9,10 Our results demonstrate that robust cell-derived vascular tissue ring generation can be achieved within a short time period, and offers the opportunity for direct and quantitative assessment of the contributions of cells and cell-derived matrix (CDM) to vascular tissue structure and function.

This article outlines a versatile method to create cell-derived tissue rings by cellular self-assembly. Smooth muscle cells seeded into ring-shaped agarose wells aggregate and contract to form robust three-dimensional (3D) tissues within 7 days. Millimeter-scale tissue rings are conducive to mechanical testing and serve as building blocks for tissue assembly.

Regissert Cellular Self-Assembly å dikte Cell-Avledet Tissue Rings for Biomekaniske Analysis and Tissue Engineering

Each year, hundreds of thousands of patients undergo coronary artery bypass surgery in the United States.1 Approximately one third of these patients do ...

Determination of the Transport Rate of Xenobiotics and Nanomaterials Across the Placenta using the ex vivo Human Placental Perfusion Model

Decades ago the human placenta was thought to be an impenetrable barrier between mother and unborn child. However, the discovery of thalidomide-induced birth defects and many later studies afterwards proved the opposite. Today several harmful xenobiotics like nicotine, heroin, methadone or drugs as well as environmental pollutants were described to overcome this barrier. With the growing use of nanotechnology, the placenta is likely to come into contact with novel nanoparticles either accidentally through exposure or intentionally in the case of potential nanomedical applications. Data from animal experiments cannot be extrapolated to humans because the placenta is the most species-specific mammalian organ 1. Therefore, the ex vivo dual recirculating human placental perfusion, developed by Panigel et al. in 1967 2 and continuously modified by Schneider et al. in 1972 3, can serve as an excellent model to study the transfer of xenobiotics or particles.
Here, we focus on the ex vivo dual recirculating human placental perfusion protocol and its further development to acquire reproducible results.
The placentae were obtained after informed consent of the mothers from uncomplicated term pregnancies undergoing caesarean delivery. The fetal and maternal vessels of an intact cotyledon were cannulated and perfused at least for five hours. As a model particle fluorescently labelled polystyrene particles with sizes of 80 and 500 nm in diameter were added to the maternal circuit. The 80 nm particles were able to cross the placental barrier and provide a perfect example for a substance which is transferred across the placenta to the fetus while the 500 nm particles were retained in the placental tissue or maternal circuit. The ex vivo human placental perfusion model is one of few models providing reliable information about the transport behavior of xenobiotics at an important tissue barrier which delivers predictive and clinical relevant data.

Determination of the Transport Rate of Xenobiotics and Nanomaterials Across the Placenta using the ex vivo Human Placental Perfusion Model

The ex vivo dual recirculating human placental perfusion model can be used to investigate the transfer of xenobiotics and nanoparticles across the human placenta. In this video protocol we describe the equipment and techniques required for a successful execution of a placenta perfusion.

Fastsettelse av Transport Valuta xenobiotics og nanomaterialer over placenta ved hjelp<em&gt; Ex vivo</em&gt; Menneskelig placentaperfusjon Model

Decades ago the human placenta was thought to be an impenetrable barrier between mother and unborn child. However, the discovery of thalidomide-induced ...

Biomechanical Characterization of Human Soft Tissues Using Indentation and Tensile Testing

Regenerative medicine aims to engineer materials to replace or restore damaged or diseased organs. The mechanical properties of such materials should mimic the human tissues they are aiming to replace; to provide the required anatomical shape, the materials must be able to sustain the mechanical forces they will experience when implanted at the defect site. Although the mechanical properties of tissue-engineered scaffolds are of great importance, many human tissues that undergo restoration with engineered materials have not been fully biomechanically characterized. Several compressive and tensile protocols are reported for evaluating materials, but with large variability it is difficult to compare results between studies. Further complicating the studies is the often destructive nature of mechanical testing. Whilst an understanding of tissue failure is important, it is also important to have knowledge of the elastic and viscoelastic properties under more physiological loading conditions.
This report aims to provide a minimally destructive protocol to evaluate the compressive and tensile properties of human soft tissues. As examples of this technique, the tensile testing of skin and the compressive testing of cartilage are described. These protocols can also be directly applied to synthetic materials to ensure that the mechanical properties are similar to the native tissue. Protocols to assess the mechanical properties of human native tissue will allow a benchmark by which to create suitable tissue-engineered substitutes.

Tissue biomechanics is important for maintaining cell shape and function and for determining phenotype. This report demonstrates non-destructive mechanical protocols for characterizing elastic and viscoelastic properties of human soft tissues, which can be directly applied to tissue-engineered substrates to allow a close matching of engineered materials to native tissue.

Biomekaniske Karakterisering av menneske bløtvev Bruke Innrykk og Strekkprøving

Regenerative medicine aims to engineer materials to replace or restore damaged or diseased organs. The mechanical properties of such materials should ...

An Experimental and Finite Element Protocol to Investigate the Transport of Neutral and Charged Solutes across Articular Cartilage

Osteoarthritis (OA) is a debilitating disease that is associated with degeneration of articular cartilage and subchondral bone. Degeneration of articular cartilage impairs its load-bearing function substantially as it experiences tremendous chemical degradation, i.e. proteoglycan loss and collagen fibril disruption. One promising way to investigate chemical damage mechanisms during OA is to expose the cartilage specimens to an external solute and monitor the diffusion of the molecules. The degree of cartilage damage (i.e. concentration and configuration of essential macromolecules) is associated with collisional energy loss of external solutes while moving across articular cartilage creates different diffusion characteristics compared to healthy cartilage. In this study, we introduce a protocol, which consists of several steps and is based on previously developed experimental micro-Computed Tomography (micro-CT) and finite element modeling. The transport of charged and uncharged iodinated molecules is first recorded using micro-CT, which is followed by applying biphasic-solute and multiphasic finite element models to obtain diffusion coefficients and fixed charge densities across cartilage zones.

We propose a protocol to investigate the transport of charged and uncharged molecules across articular cartilage with the aid of recently developed experimental and numerical methods.

En eksperimentell og Finite Element-protokollen for å undersøke Transport av nøytrale og siktet Oppløste stoffer over Leddbrusk

Osteoarthritis (OA) is a debilitating disease that is associated with degeneration of articular cartilage and subchondral bone. Degeneration of articular ...

A Test Bed to Examine Helmet Fit and Retention and Biomechanical Measures of Head and Neck Injury in Simulated Impact

Conventional wisdom and the language in international helmet testing and certification standards suggest that appropriate helmet fit and retention during an impact are important factors in protecting the helmet wearer from impact-induced injury. This manuscript aims to investigate impact-induced injury mechanisms in different helmet fit scenarios through analysis of simulated helmeted impacts with an anthropometric test device (ATD), an array of headform acceleration transducers and neck force/moment transducers, a dual high speed camera system, and helmet-fit force sensors developed in our research group based on Bragg gratings in optical fiber. To simulate impacts, an instrumented headform and flexible neck fall along a linear guide rail onto an anvil. The test bed allows simulation of head impact at speeds up to 8.3 m/s, onto impact surfaces that are both flat and angled. The headform is fit with a crash helmet and several fit scenarios can be simulated by making context specific adjustments to the helmet position index and/or helmet size. To quantify helmet retention, the movement of the helmet on the head is quantified using post-hoc image analysis. To quantify head and neck injury potential, biomechanical measures based on headform acceleration and neck force/moment are measured. These biomechanical measures, through comparison with established human tolerance curves, can estimate the risk of severe life threatening and/or mild diffuse brain injury and osteoligamentous neck injury. To our knowledge, the presented test-bed is the first developed specifically to assess biomechanical effects on head and neck injury relative to helmet fit and retention.

Using an anthropometric head and neck, optical fiber-based fit force transducers, an array of head acceleration and neck force/moment transducers, and a dual high speed camera system, we present a test bed to study helmet retention and effects on biomechanical measures of head and neck injury secondary to head impact.

En Test seng å undersøke hjelm passform og oppbevaring og biomekaniske tiltak av hodet og nakkeskade ved simulert innvirkning

Conventional wisdom and the language in international helmet testing and certification standards suggest that appropriate helmet fit and retention during ...

Methods for In Vivo Biomechanical Testing on Brachial Plexus in Neonatal Piglets

Neonatal brachial plexus palsy (NBPP) is a stretch injury that occurs during the birthing process in nerve complexes located in the neck and shoulder regions, collectively referred to as the brachial plexus (BP). Despite recent advances in obstetrical care, the problem of NBPP continues to be a global health burden with an incidence of 1.5 cases per 1,000 live births. More severe types of this injury can cause permanent paralysis of the arm from the shoulder down. Prevention and treatment of NBPP warrants an understanding of the biomechanical and physiological responses of newborn BP nerves when subjected to stretch. Current knowledge of the newborn BP is extrapolated from adult animal or cadaveric BP tissue instead of in vivo neonatal BP tissue. This study describes an in vivo mechanical testing device and procedure to conduct in vivo biomechanical testing in neonatal piglets. The device consists of a clamp, actuator, load cell, and camera system that apply and monitor in vivo strains and loads until failure. The camera system also allows monitoring of the failure location during rupture. Overall, the presented method allows for a detailed biomechanical characterization of neonatal BP when subjected to stretch.

Methods for In Vivo Biomechanical Testing on Brachial Plexus in Neonatal Piglets

Presented here are methods to perform in vivo biomechanical testing on brachial plexus in a neonatal piglet model.

Metoder for in vivo biomekaniske testing på brachialis plexus i nyfødt grisunger

Neonatal brachial plexus palsy (NBPP) is a stretch injury that occurs during the birthing process in nerve complexes located in the neck and shoulder ...

Biaxial Basal Tone and Passive Testing of the Murine Reproductive System Using a Pressure Myograph

The female reproductive organs, specifically the vagina and cervix, are composed of various cellular components and a unique extracellular matrix (ECM). Smooth muscle cells exhibit a contractile function within the vaginal and cervical walls. Depending on the biochemical environment and the mechanical distension of the organ walls, the smooth muscle cells alter the contractile conditions. The contribution of the smooth muscle cells under baseline physiological conditions is classified as a basal tone. More specifically, a basal tone is the baseline partial constriction of smooth muscle cells in the absence of hormonal and neural stimulation. Furthermore, the ECM provides structural support for the organ walls and functions as a reservoir for biochemical cues. These biochemical cues are vital to various organ functions, such as inciting growth and maintaining homeostasis. The ECM of each organ is composed primarily of collagen fibers (mostly collagen types I, III, and V), elastic fibers, and glycosaminoglycans/proteoglycans. The composition and organization of the ECM dictate the mechanical properties of each organ. A change in ECM composition may lead to the development of reproductive pathologies, such as pelvic organ prolapse or premature cervical remodeling. Furthermore, changes in ECM microstructure and stiffness may alter smooth muscle cell activity and phenotype, thus resulting in the loss of the contractile force.
In this work, the reported protocols are used to assess the basal tone and passive mechanical properties of the nonpregnant murine vagina and cervix at 4-6 months of age in estrus. The organs were mounted in a commercially available pressure myograph and both pressure-diameter and force-length tests were performed. Sample data and data analysis techniques for the mechanical characterization of the reproductive organs are included. Such information may be useful for constructing mathematical models and rationally designing therapeutic interventions for women&#8217;s health pathologies.

This protocol utilized a commercially available pressure myograph system to perform pressure myograph testing on the murine vagina and cervix. Utilizing media with and without calcium, the contributions of the smooth muscle cells (SMC) basal tone and passive extracellular matrix (ECM) were isolated for the organs under estimated physiological conditions.

Biaksiale basal tone og passiv testing av murine reproduktive system ved hjelp av en Pressure Myograph

The female reproductive organs, specifically the vagina and cervix, are composed of various cellular components and a unique extracellular matrix (ECM). ...

The Quantification of Injectability by Mechanical Testing

Injectable biomaterials are becoming increasingly popular for the minimally invasive delivery of drugs and cells. These materials are typically more viscous than traditional aqueous injections and may be semi-solid, therefore, their injectability cannot be assumed. This protocol describes a method to objectively assess the injectability of these materials using a standard mechanical tester. The syringe plunger is compressed by the crosshead at a set rate, and the force is measured. The maximum or plateau force value can then be used for comparison between samples, or to an absolute force limit. This protocol can be used with any material, and any syringe and needle size or geometry. The results obtained may be used to make decisions about formulations, syringe and needle sizes early in the translational process. Further, the effects of altering formulations on injectability may be quantified, and the optimum time to inject temporally changing materials determined. This method is also suitable as a reproducible way to examine the effects of injection on a material, to study phenomena such as self-healing and filter pressing or study the effects of injection on cells. This protocol is faster and more directly applicable to injectability than rotational rheology, and requires minimal post processing to obtain key values for direct comparisons.

Presented here is a protocol for quantitatively evaluating the injectability of a material through a syringe-needle system using a standard mechanical testing rig.

Kvantifiseringen av injiserbarhet ved mekanisk testing

Injectable biomaterials are becoming increasingly popular for the minimally invasive delivery of drugs and cells. These materials are typically more ...

Optical Coherence Tomography Based Biomechanical Fluid-Structure Interaction Analysis of Coronary Atherosclerosis Progression

In this paper, we present a complete workflow for the biomechanical analysis of atherosclerotic plaque in the coronary vasculature. With atherosclerosis as one of the leading causes of global death, morbidity and economic burden, novel ways of analyzing and predicting its progression are needed. One such computational method is the use of fluid-structure interaction (FSI) to analyze the interaction between the blood flow and artery/plaque domains. Coupled with in vivo imaging, this approach could be tailored to each patient, assisting in differentiating between stable and unstable plaques. We outline the three-dimensional reconstruction process, making use of intravascular Optical Coherence Tomography (OCT) and invasive coronary angiography (ICA). The extraction of boundary conditions for the simulation, including replicating the three-dimensional motion of the artery, is discussed before the setup and analysis is conducted in a commercial finite element solver. The procedure for describing the highly nonlinear hyperelastic properties of the artery wall and the pulsatile blood velocity/pressure is outlined along with setting up the system coupling between the two domains. We demonstrate the procedure by analyzing a non-culprit, mildly stenotic, lipid-rich plaque in a patient following myocardial infarction. Established and emerging markers related to atherosclerotic plaque progression, such as wall shear stress and local normalized helicity, respectively, are discussed and related to the structural response in the artery wall and plaque. Finally, we translate the results to potential clinical relevance, discuss limitations, and outline areas for further development. The method described in this paper shows promise for aiding in the determination of sites at risk of atherosclerotic progression and, hence, could assist in managing the significant death, morbidity, and economic burden of atherosclerosis.

There is a need to determine which atherosclerotic lesions will progress in the coronary vasculature to guide intervention before myocardial infarction occurs. This article outlines the biomechanical modeling of arteries from Optical Coherence Tomography using fluid-structure interaction techniques in a commercial finite element solver to help predict this progression.

Optisk koherenstomografibasert biomekanisk væskestrukturinteraksjonsanalyse av koronar ateroskleroseprogresjon

In this paper, we present a complete workflow for the biomechanical analysis of atherosclerotic plaque in the coronary vasculature. With atherosclerosis ...

Construction of a Human Aorta Smooth Muscle Cell Organ-On-A-Chip Model for Recapitulating Biomechanical Strain in the Aortic Wall

Conventional two-dimensional cell culture techniques and animal models have been used in the study of human thoracic aortic aneurysm and dissection (TAAD). However, human TAAD sometimes cannot be characterized by animal models. There is an apparent species gap between clinical human studies and animal experiments that may hinder the discovery of therapeutic drugs. In contrast, the conventional cell culture model is unable to simulate in vivo biomechanical stimuli. To this end, microfabrication and microfluidic techniques have developed greatly in recent years, providing novel techniques for establishing organoids-on-a-chip models that replicate the biomechanical microenvironment. In this study, a human aorta smooth muscle cell organ-on-a-chip (HASMC-OOC) model was developed to simulate the pathophysiological parameters of aortic biomechanics, including the amplitude and frequency of cyclic strain experienced by human aortic smooth muscle cells (HASMCs) that play a vital role in TAAD. In this model, the morphology of HASMCs became elongated in shape, aligned perpendicularly to the strain direction, and presented a more contractile phenotype under strain conditions than under static conventional conditions. This was consistent with the cell orientation and phenotype in native human aortic walls. Additionally, using bicuspid aortic valve-related TAAD (BAV-TAAD) and tricuspid aortic valve-related TAAD (TAV-TAAD) patient-derived primary HASMCs, we established BAV-TAAD and TAV-TAAD disease models, which replicate HASMC characteristics in TAAD. The HASMC-OOC model provides a novel in vitro platform that is complementary to animal models for further exploring the pathogenesis of TAAD and discovering therapeutic targets.

Here, we developed a human aorta smooth muscle cell organ-on-a-chip model to replicate the in vivo biomechanical strain of smooth muscle cells in the human aortic wall.

Konstruksjon av en human aorta glatt muskelcelle organ-on-a-chip modell for rekapitulere biomekanisk belastning i aortaveggen

Conventional two-dimensional cell culture techniques and animal models have been used in the study of human thoracic aortic aneurysm and dissection ...