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 stöddes av NIH/NIAMS (R01 AR055580, R01 AR057836).

Djurstudier godkändes av Columbia University institutionella djuromsorg och användning kommittén. Möss som används i denna studie var av en C57BL/6J bakgrund och köptes från Jackson Laboratory (Bar Harbor, ME, USA). De var inhysta i patogen-fri barriär villkor och tillhandahölls mat och vatten AD libitum.
1. utveckling av Custom-Fit 3D tryckta fixturer för gripande ben
<ol><li>Ben bild förvärv och 3D ben modell konstruktion<ol><li>Dissekera benet av intresse för förberedelse f?...

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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. 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Murina djurmodeller används ofta för att studera sena sjukdomar, men karaktärisering av deras mekaniska egenskaper är utmanande och ovanligt i litteraturen. Syftet med detta protokoll är att beskriva en tidseffektiv och reproducerbar metod för Dragprovning av murina senor. De nya metoderna minskade den tid som krävs för att testa ett prov från timmar till minuter och eliminerade en stor gripande artefakt som var ett vanligt problem i tidigare metoder.
Flera steg som beskrivs i detta p...

Senor störningar är vanliga och mycket utbredda bland åldrande, atletisk, och aktiva populationer1,2,3. I USA, 16 400 000 bindväv skador rapporteras varje år4 och står för 30% av alla skada-relaterade läkare kontor besök3,5,6,7, 8. De mest drabbade platserna inkluderar rotatorkuffen, hälsenan och patellar senan9. Även om en mängd icke-operativa och operativa behandlingar har undersökts, inklusive antiinflammatoriska läkemedel, rehabilitering, och kirurgisk reparation, resultaten förblir fattiga, med begränsad återgång till funktion och hög grad av misslyckande5, 6. Dessa dåliga kliniska resultat har motiverat grundläggande och translationella studier som syftar till att förstå tendinopati och utveckla nya behandlingsmetoder.
Drag biomekaniska egenskaper är de primära kvantitativa resultaten definiera senan funktion. Därför, laboratorie karakterisering av tendinopati och behandlingseffekt måste innehålla en rigorös testning av senan draghållfasthet egenskaper. Ett flertal studier har beskrivit metoder för att bestämma de biomekaniska egenskaperna hos senor från djurmodeller som råttor, får, hundar och kaniner10,11,12. Emellertid, få studier har testat de biomekaniska egenskaperna hos murina senor, främst på grund av svårigheterna att grippa de små vävnaderna för Dragprovning. Som murin modeller har många fördelar för mekanistiskt studera tendinopati, inklusive genetisk manipulation, omfattande reagenser alternativ, och låg kostnad, utveckling av noggranna och effektiva metoder för att biomekaniskt testa murina vävnader behövs.
För att korrekt testa de mekaniska egenskaperna hos senor, måste vävnaden grisas effektivt, utan att halka eller artifakto Riva på greppet gränssnittet eller sprickbildning i tillväxtplattan. I många fall, särskilt för korta senor, är benet grep i ena änden och senan är gripen på den andra änden. Ben är vanligtvis säkras genom att bädda in dem i material som epoxiharts13 och polymetylmetakrylat14,15. Senor är ofta placerade mellan två lager av sandpapper, limmade med cyanoakrylat, och säkras med kompressions klämmor (om tvärsnittet är platt) eller i ett fryst medium (om tvärsnittet är stort)15,16,17 . Dessa metoder har tillämpats på biomekaniskt testa murina senor, men utmaningar uppstår på grund av den lilla storleken på proverna och efterlevnaden av tillväxtplattan, som aldrig ossifies18. Till exempel, diametern på den murina överarmsbenets huvudet är bara några millimeter, vilket gör gripande av benet svårt. Specifikt, Dragprovning av murina supraspinatus senan-till-benprover resulterar ofta i misslyckande på tillväxtplattan snarare än i senan eller på senan enthesis. På samma sätt är biomekanisk testning av hälsenan utmanande. Även om hälsenan är större än andra murina senor, calcaneus är liten, gör gripande av detta ben svårt. Benet kan avlägsnas, följt av gripande de två sena ändar; emellertid, detta utesluter testning av senan-till-ben kvarstad. Andra grupper rapport gripande calcaneus ben med hjälp av skräddarsydda armaturer19,20, förankring av klämmor21, fastställande i själv härdning plast cement22 eller med en konisk form plats22, men dessa tidigare metoder förblir begränsade av låg reproducerbarhet, hög gripande felfrekvenser, och tråkiga förberedelse krav.
Syftet med den aktuella studien var att utveckla en noggrann och effektiv metod för drag biomekanisk testning av murina senor, med fokus på supraspinatus och Hälsensenor som exempel. Med hjälp av en kombination av 3D rekonstruktioner från infödda ben anatomi, solid modellering, och additiv tillverkning, en ny metod utvecklades för att greppa benen. Dessa fixturer säkrade effektivt benen, förhindrade tillväxtplattan misslyckande, minskad preparatet förberedelsetid, och ökad testning reproducerbarhet. Den nya metoden är lätt anpassningsbar för att testa andra murina senor samt senor hos råttor och andra djur.

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			<td >Dissovle 1g in 100 ml ultrapure water to make 1% agarose&#160;</td>
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		<tr >
			<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

Sena störningar är vanliga, drabbar människor i alla åldrar, och är ofta handikappande. Standard behandlingar, såsom antiinflammatoriska läkemedel, rehabilitering, och kirurgisk reparation, ofta misslyckas. För att definiera senan funktion och demonstrera effekten av nya behandlingar, de mekaniska egenskaperna hos senor från djurmodeller måste bestämmas noggrant. Murina djurmodeller är nu allmänt används för att studera sena sjukdomar och utvärdera nya behandlingar för tendinopatier; men att fastställa de mekaniska egenskaperna hos mus senor har varit utmanande. I denna studie, ett nytt system utvecklades för senan mekaniska tester som innehåller 3D-tryckta fixturer som exakt matchar anatomies av humerus och calcaneus att mekaniskt testa supraspinatus senor och Achilles senor, respektive. Dessa armaturer utvecklades med hjälp av 3D rekonstruktioner av infödda ben anatomi, solid modellering, och additiv tillverkning. Den nya metoden elimineras artifaktoriska gripande misslyckanden (t. ex., misslyckande vid tillväxtplattan misslyckande snarare än i senan), minskade totala test tid, och ökad reproducerbarhet. Dessutom är denna nya metod lätt anpassningsbar för att testa andra murina senor och senor från andra djur.

3D-tryckta fixturer användes för att testa 8-veckors gammal murina supraspinatus och Hälsensenor. Alla mekaniskt testade prover misslyckades på enthesis, som kännetecknas av microCT skanningar, visuell inspektion och videoanalys efter Dragprovning. En en-till-en jämförelse av de tidigare och nuvarande metoder för supraspinatus senan testning i vårt laboratorium visas i figur 3. I den tidigare metoden28,29,<sup cla...

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

Biomechanical Testing of Murine Tendons

Protokollet beskriver effektiva och reproducerbara drag biomekaniska provningsmetoder för murina senor genom användning av Custom-Fit 3D tryckta fixturer.

Biomekanisk testning av murina senor

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

Protokollet beskriver en effektiv och reproducerbar metod för biomekanisk testning av mussenor genom återanvändbara custom-fit 3D tryckta fixturer. De nya metoderna minskar den tid som krävs för att testa provet från timmar till minuter och eliminera en större gripande artefakt som var ett vanligt problem i tidigare metoder. Denna metod är inte begränsad till supraspinatus och hälsenan.Den kan enkelt anpassas till att testa andra mussenor och senor från större djur. För att säkerställa reproducerbarhet och effektivitet av tillvägagångssättet, flera cykler av design prototyping och validering kan behövas för fixturer som inte beskrivs här. Till att börja med utför en mikrodatortomografiskanning av hela benet i agarosgeln.Efter rekonstruktion i tvärsnittsbilder väljer du kommandot Arkiv Öppet för att öppna fildatauppsättningen. Öppna dialogrutan Inställningar och välj fliken Avancerat. Använd den adaptiva renderingsalgoritmen för att konstruera 3D-modellerna som ger jämnare ytdetalj.Använd 10 som parametern för ortsaparameter vilket definierar avståndet i pixlar till grannpunkten som används för att hitta objektkanten. Minimera toleransen till 0,1 för att minska filstorleken. Om du vill ange volymen av intresse väljer du manuellt två bilder som ska anges som över- och underkant i det valda VOI-området och flyttar sedan till den andra sidan, Region av intresse.Välj manuellt den region av intresse på en enda tvärsnittsbild. Upprepa välja roi för varje 10 till 15 tvärsnittsbilder. Därefter flyttar du till den tredje sidan, Binär markering.På Menyn Histogram klickar du på Från datauppsättning för att visa histogramfördelningen av ljusstyrka från alla bilder av datauppsättningen. Klicka även på menyn Skapa en 3D-modell på menyn Histogram. Spara en 3D-modell av benet i STL-filformat.I meshmixerprogramvaran importerar du nät och väljer Alla att redigera. Välj Producera från verktygsuppsättningen redigera, välj sedan Triangelbudget från verktygsuppsättningen Minska målet. Minska tricounten och acceptera ändringar.Resave den nyligen reducerade filen i STL-format genom att välja Export As.To design a supraspinatus tendon humeral bone, använd en solid-modellering datorstödd designprogram för att skapa en anpassad-fit modell av humerus-gripande fixtur. Öppna STL-formatfilen av humerusbenet i ett solid-modelleringsprogram och spara som en delfil i SLDPRT-format. Öppna sedan Part-filen för att manuellt skapa tre anatomiskt relevanta plan, till exempel sagittal, koronal och tvärgående.Klicka på File New för att skapa den solida blockkomponentdelen. Klicka på File New för att skapa en monteringsmodell med två komponenter, det heldragna blocket och antingen höger eller vänster överarmsben. Definiera orienteringen av benet inom blocket för att säkerställa vinkeln mellan senan och ben för att vara 180 grader.Se till att hela benvolymen passar inuti blocket. Markera blocket i fönstret Sammansättning och klicka på Redigera komponent i verktygsfältet Sammansättningen. Klicka på Infoga, Funktioner, Hålighet.Välj Enhetlig skalning och ange 0 %som det värde som ska skalas i alla riktningar. Undertryck bendelen och spara monteringen som en del. Öppna cylindern med kavitetsdel.Skapa en skiss, se till att bara lämna 0,5 millimeter ovanför humeralhuvudet. Välj Extruded Cut från Funktioner. Skär monteringen längs sagittal planet för att skapa två symmetriska komponenter som passar benet anteriorly och posteriort.Skär monteringsdelen längs det sagittala planet för att skapa två symmetriska komponenter som passar benet anteriorly och posteriort. Det är viktigt att säkerställa humeral huvudet för att förhindra tillväxt plattan misslyckande och att definiera en stram clearance som undviker att koppla bort överarmsprovet från modellen under testning. Fortsätt enligt beskrivningen i manuskriptet för att avsluta den bakre komponenten och främre komponenten.Spara båda komponenterna som separata delfiler. Tryck nu på Infoga mönster, Spegel och välj Spegel för att skapa 3D spegelmodeller för varje komponent i fixturen för den motsatta extremiteten. Välj framsida som en spegel ansikte vanligt.Markera den del som kroppen att spegla. Välj spegelplanet och skapa en skiss som omfattar allt material. Välj Från Funktioner, välj Extruded Cut för att ta bort den ursprungliga delen och för att endast hålla speglad del.Klicka på botten av delen och använda som ett plan för att göra en skiss. Klicka på Skisstext och lägg till L eller R.Detta lägger till en etch på fixturernas undersida för att skilja mellan vänster och höger sida. Spara alla fixture delar i STL standard filformat i förberedelse för 3D-utskrift.För att dissekera supraspinatusmuskel-senan, humerus ben exemplar, först placera avlivas musen i en benägen position och göra ett snitt i huden ovanifrån armbågen i framutsågen mot axeln. Använd forceps för att försiktigt ta bort huden med trubbig dissektion så att muskulaturen på axeln syns. Ta bort vävnaden som omger överarmsbenet tills benet exponeras.Håll överarmsmussen med pincett och försiktigt ta bort deltoid och trapezius muskler för att exponera coracoacromial arch. Identifiera AC-leden och separera försiktigt nyckelbenet från acromionen med ett skalpellblad. Var noga med att inte skada supraspinatussenan och dess beniga fastsättning, ta bort muskeln från sin skulderbladsfäste med hjälp av ett skalpellblad.Lösgör humeralhuvudet från glenoid och lacerate ledkapseln och infraspinatus subscapularis och teres mindre senor. Disarticulate armbågsleden för att separera överarmsbenet från armbågsbenet och radien. Isolera humerus-supraspinatus sena muskel exemplar och rensa bort överflödiga mjuka vävnader på överarms- och humeral huvudet.För att dissekera hälsenan, calcaneus ben, placera en avlivad mus i en utsatt position. Var noga med att inte skada hälsenan och dess beniga fastsättning, ta bort huden med trubbig dissektion så att muskulaturen runt fotleden och knäleden exponeras. Med hjälp av en skalpell blad, med början vid Achilles senan-calcaneus fastsättning, försiktigt lossa gastrocnemius muskeln från dess proximala bilagor.Försiktigt disarticulate calcaneus från de olika intilliggande ben och isolera Achilles senan-calcaneus exemplar och rensa bort överflödiga mjuka vävnader. För att bestämma tvärsnittsarean av senan, sätt benet upp och ner för att hänga upp exemplaret i kryoröret fylld med agarosgel med benet i agarosgeln och senan och muskeln utanför. Efter skanningen med hjälp av mikrokompskivad tomografi, försiktigt bort muskeln från senan med hjälp av en skalpell blad.Sätt in benet i den 3D-tryckta fixturen och fäst dem i testrutnäten. Sätt in och limma senan mellan ett vikt tunt mjukpapper och kläm fast det med hjälp av tunna filmgrepp. Sätt in provet och greppen i ett testbad av PBS vid 37 grader Celsius och utför ett mekaniskt test.I denna studie, med hjälp av återanvändbara 3D tryckta fixturer att greppa ben, var exemplar förberedelse tid minskas från timmar till minuter. Representativa belastning deformation kurvor för dragprovning av supraspinatus senan med hjälp av nuvarande metoder elimineras större gripande artefakt såsom tillväxt plattan misslyckande. De mekaniska egenskaperna hos supraspinatus och hälsenor visar en signifikant effekt av kön baserat på oparade T-tester med P-värde mindre än 0,05.Micro CT framgångsrikt mätt tvärsnittsytan längs längden av supraspinatus sena längs längden av Hälsenan. Det är viktigt att komma ihåg att varje anatomisk webbplats har specifika designkriterier som är nödvändiga för effektiv gripande. Därför bör konstruktionen för varje fixtur anpassas därefter.Förutom dragtestning till fel kan dessa fixturer användas för cykliska belastningstester, som ger information om senutmattning och viskösastiska egenskaper. Karakterisera mekaniska egenskaper murine senor är ovanligt i litteraturen på grund av ett antal skäl, inklusive svårigheten att gripa dessa små vävnader, tråkiga och tidskrävande provberedning metoder och tillväxt plattan frakturer. Detta protokoll presenterar en tidseffektiv och reproducerbar metod för att testa mussenor som har eliminerat artefaktgrepp misslyckanden och har tredubblat antalet exemplar som kan testas 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.

Riktad Cellular Self-Assembly att tillverka-cellerna Tissue Ringar för Biomekaniska analys och 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.

Fastställande av transport Andel Xenobiotika och nanomaterial igenom moderkakan med<em&gt; Ex vivo</em&gt; Human placentaperfusionen 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.

Biomekanisk karakterisering av mänskliga mjuka vävnader med hjälp av indrag och dragprovning

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 Experimental och Finite Element protokoll för att undersöka transport av neutrala och laddade Lösta ämnen över Ledbrosk

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.

Ett Test-säng att undersöka hjälm passform och Retention och biomekaniska åtgärder av huvud- och nackskador i simulerade inverkan

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 för in vivo biomekaniska tester på brachial plexus i neonatal smågrisar

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.

Biaxial basal ton och passiv testning av murina reproduktionssystemet med hjälp av en Tryckmyograph

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.

Kvantifieringen av injicerbarhet genom mekanisk provning

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 koherenstomografibaserad biomekanisk vätskestrukturinteraktionsanalys av koronar åderförkalkning progression

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.

Konstruktion av en human aorta glatt muskelcell organ-on-a-chip modell för rekapitulering av biomekanisk belastning i aortaväggen

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