The authors would like to thank Gabriel Arom and Michael Yeranosian for their technical contributions to earlier iterations of this project. This project was funded by the OREF Clinician Scientist Training Grant (NL), H H Lee Surgical Research Grant (NL), Veterans Administration BLR&#38;D Merit Review 1 I01 BX00012601 (DM) and Musculoskeletal Transplantation Foundation Young Investigator Award (FP).

NOTE: All animal surgeries were approved by the local veterinary staff and animal use committee prior to commencing the experiments.
1. Preparation of Electrospun Polycaprolactone Scaffolds
<ol>
	<li>Weigh and dissolve medical grade ester terminated poly (&#949;-caprolactone) in granule form in 1,1,1,3,3,3-hexafluoro-2-propanol to create a 10% w/w solution of the PCL polymer. Let the solution stir using a stir plate for at least 3 hr to ensure a homogenous solution.</li>
	<li>Electrospin the...

<ol>
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J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+results+of+arthroscopic+single-bundle+transtibial+posterior+cruciate+ligament+reconstruction:+a+systematic+review.">Clinical results of arthroscopic single-bundle transtibial posterior cruciate ligament reconstruction: a systematic review.</a> Am J Sports Med. 39 (2), 425-434 (2011).</li><li>Andersson, C., Odensten, M., Gillquist, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Knee+function+after+surgical+or+nonsurgical+treatment+of+acute+rupture+of+the+anterior+cruciate+ligament:+a+randomized+study+with+a+long-term+follow-up+period.">Knee function after surgical or nonsurgical treatment of acute rupture of the anterior cruciate ligament: a randomized study with a long-term follow-up period.</a> Clin Orthop Relat Res. (264), 255-263 (1991).</li><li>Klimkiewicz, J. J., Petrie, R. S., Harner, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surgical+treatment+of+combined+injury+to+anterior+cruciate+ligament,+posterior+cruciate+ligament,+and+medial+structures.">Surgical treatment of combined injury to anterior cruciate ligament, posterior cruciate ligament, and medial structures.</a> Clin Sports Med. 19 (3), 479-492 (2000).</li><li>Petrigliano, F. A., McAllister, D. R., Wu, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue+engineering+for+anterior+cruciate+ligament+reconstruction:+a+review+of+current+strategies.">Tissue engineering for anterior cruciate ligament reconstruction: a review of current strategies.</a> Arthroscopy. 22 (4), 441-451 (2006).</li><li>Groot, J. 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=Use+of+porous+polyurethanes+for+meniscal+reconstruction+and+meniscal+prostheses.">Use of porous polyurethanes for meniscal reconstruction and meniscal prostheses.</a> Biomaterials. 17 (2), 163-173 (1996).</li><li>Leong, N. L., Petrigliano, F. A., McAllister, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Current+tissue+engineering+strategies+in+anterior+cruciate+ligament+reconstruction.">Current tissue engineering strategies in anterior cruciate ligament reconstruction.</a> J Biomed Mater Res A. 102 (5), 1614-1624 (2014).</li><li>Duling, R. R., Dupaix, R. B., Katsube, N., Lannutti, 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+characterization+of+electrospun+polycaprolactone+(PCL):+a+potential+scaffold+for+tissue+engineering.">Mechanical characterization of electrospun polycaprolactone (PCL): a potential scaffold for tissue engineering.</a> J Biomech Eng. 130 (1), 011006 (2008).</li><li>Shao, Z., 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=Polycaprolactone+electrospun+mesh+conjugated+with+an+MSC+affinity+peptide+for+MSC+homing+in+vivo.">Polycaprolactone electrospun mesh conjugated with an MSC affinity peptide for MSC homing in vivo.</a> Biomaterials. 33 (12), 3375-3387 (2012).</li><li>Tillman, B. W., 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+in+vivo+stability+of+electrospun+polycaprolactone-collagen+scaffolds+in+vascular+reconstruction.">The in vivo stability of electrospun polycaprolactone-collagen scaffolds in vascular reconstruction.</a> Biomaterials. 30 (4), 583-588 (2009).</li><li>Wise, S. G., 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+multilayered+synthetic+human+elastin/polycaprolactone+hybrid+vascular+graft+with+tailored+mechanical+properties.">A multilayered synthetic human elastin/polycaprolactone hybrid vascular graft with tailored mechanical properties.</a> Acta Biomater. 7 (1), 295-303 (2011).</li><li>Vargel, I., Korkusuz, P., Mencelo&#287;lu, Y. Z., Pi&#351;kin, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+performance+of+antibiotic+embedded+electrospun+PCL+membranes+for+prevention+of+abdominal+adhesions.">In vivo performance of antibiotic embedded electrospun PCL membranes for prevention of abdominal adhesions.</a> J Biomed Mater Res B Appl Biomater. 81 (2), 530-543 (2007).</li><li>Cao, H., McHugh, K., Chew, S. Y., Anderson, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+topographical+effect+of+electrospun+nanofibrous+scaffolds+on+the+in+vivo+and+in+vitro+foreign+body+reaction.">The topographical effect of electrospun nanofibrous scaffolds on the in vivo and in vitro foreign body reaction.</a> J Biomed Mater Res A. 93 (3), 1151-1159 (2010).</li><li>Joshi, V. S., Lei, N. Y., Walthers, C. M., Wu, B., Dunn, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Macroporosity+enhances+vascularization+of+electrospun+scaffolds.">Macroporosity enhances vascularization of electrospun scaffolds.</a> J Surg Res. 183 (1), 18-26 (2013).</li><li>Pham, Q. P., Sharma, U., Mikos, A. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrospun+poly(epsilon-caprolactone)+microfiber+and+multilayer+nanofiber/microfiber+scaffolds:+characterization+of+scaffolds+and+measurement+of+cellular+infiltration.">Electrospun poly(epsilon-caprolactone) microfiber and multilayer nanofiber/microfiber scaffolds: characterization of scaffolds and measurement of cellular infiltration.</a> Biomacromolecules. 7 (10), 2796-2805 (2006).</li><li>Vaz, C. M., van Tuijl, S., Bouten, C. V., Baaijens, F. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+of+scaffolds+for+blood+vessel+tissue+engineering+using+a+multi-layering+electrospinning+technique.">Design of scaffolds for blood vessel tissue engineering using a multi-layering electrospinning technique.</a> Acta Biomater. 1 (5), 575-582 (2005).</li><li>Kawamura, S., Ying, L., Kim, H. J., Dynybil, C., Rodeo, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Macrophages+accumulate+in+the+early+phase+of+tendon-bone+healing.">Macrophages accumulate in the early phase of tendon-bone healing.</a> J Orthop Res. 23 (6), 1425-1432 (2005).</li><li>Hays, P. 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=The+role+of+macrophages+in+early+healing+of+a+tendon+graft+in+a+bone+tunnel.">The role of macrophages in early healing of a tendon graft in a bone tunnel.</a> J Bone Joint Surg Am. 90 (3), 565-579 (2008).</li><li>Dagher, E., 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=Immobilization+modulates+macrophage+accumulation+in+tendon-bone+healing.">Immobilization modulates macrophage accumulation in tendon-bone healing.</a> Clin Orthop Relat Res. 467 (1), 281-287 (2009).</li><li>Bedi, 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=Effect+of+early+and+delayed+mechanical+loading+on+tendon-to-bone+healing+after+anterior+cruciate+ligament+reconstruction.">Effect of early and delayed mechanical loading on tendon-to-bone healing after anterior cruciate ligament reconstruction.</a> J Bone Joint Surg Am. 92 (14), 2387-2401 (2010).</li><li>Bedi, A., Kawamura, S., Ying, L., Rodeo, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differences+in+tendon+graft+healing+between+the+intra-articular+and+extra-articular+ends+of+a+bone+tunnel.">Differences in tendon graft healing between the intra-articular and extra-articular ends of a bone tunnel.</a> HSS J. 5 (1), 51-57 (2009).</li><li>Fu, S. 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=Effect+of+graft+tensioning+on+mechanical+restoration+in+a+rat+model+of+anterior+cruciate+ligament+reconstruction+using+free+tendon+graft.">Effect of graft tensioning on mechanical restoration in a rat model of anterior cruciate ligament reconstruction using free tendon graft.</a> Knee Surg Sports Traumatol Arthrosc. 21 (5), 1226-1233 (2013).</li><li>Fan, H., Liu, H., Wong, E. J., Toh, S. L., Goh, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+study+of+anterior+cruciate+ligament+regeneration+using+mesenchymal+stem+cells+and+silk+scaffold.">In vivo study of anterior cruciate ligament regeneration using mesenchymal stem cells and silk scaffold.</a> Biomaterials. 29 (23), 3324-3337 (2008).</li><li>Landis, J. R., Koch, G. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+measurement+of+observer+agreement+for+categorical+data.">The measurement of observer agreement for categorical data.</a> Biometrics. 33 (1), 159-174 (1977).</li><li>Joshi, S. M., Mastrangelo, A. N., Magarian, E. M., Fleming, B. C., Murray, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Collagen-platelet+composite+enhances+biomechanical+and+histologic+healing+of+the+porcine+anterior+cruciate+ligament.">Collagen-platelet composite enhances biomechanical and histologic healing of the porcine anterior cruciate ligament.</a> Am J Sports Med. 37 (12), 2401-2410 (2009).</li><li>Leong, N. 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=In+vitro+and+in+vivo+evaluation+of+heparin+mediated+growth+factor+release+from+tissue-engineered+constructs+for+anterior+cruciate+ligament+reconstruction.">In vitro and in vivo evaluation of heparin mediated growth factor release from tissue-engineered constructs for anterior cruciate ligament reconstruction.</a> J Orthop Res. 10, (2014).</li><li>Seo, Y. 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=Increase+in+cell+migration+and+angiogenesis+in+a+composite+silk+scaffold+for+tissue-engineered+ligaments.">Increase in cell migration and angiogenesis in a composite silk scaffold for tissue-engineered ligaments.</a> J Orthop Res. 27 (4), 495-503 (2009).</li><li>Freeman, J. W., Woods, M. D., Laurencin, C. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue+engineering+of+the+anterior+cruciate+ligament+using+a+braid-twist+scaffold+design.">Tissue engineering of the anterior cruciate ligament using a braid-twist scaffold design.</a> J Biomech. 40 (9), 2029-2036 (2007).</li><li>Bashur, C. A., Shaffer, R. D., Dahlgren, L. A., Guelcher, S. A., Goldstein, A. 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E., 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+novel+device+to+apply+controlled+flexion+and+extension+to+the+rat+knee+following+anterior+cruciate+ligament+reconstruction.">A novel device to apply controlled flexion and extension to the rat knee following anterior cruciate ligament reconstruction.</a> J Biomech Eng. 134 (4), 041008 (2012).</li><li>Brophy, R. 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=Effect+of+short-duration+low-magnitude+cyclic+loading+versus+immobilization+on+tendon-bone+healing+after+ACL+reconstruction+in+a+rat+model.">Effect of short-duration low-magnitude cyclic loading versus immobilization on tendon-bone healing after ACL reconstruction in a rat model.</a> J Bone Joint Surg Am. 93 (4), 381-393 (2011).</li></ol>

The authors declare that they have no competing financial interests.

ACL injuries are a common condition in orthopaedic sports surgery, with limited options for reconstruction at the present time. In order to develop an appropriate tissue-engineered substitute for the ACL that will allow regeneration in vivo, a suitable animal model is required. In this study, the fabrication of a biodegradable engineered graft is described, as is its in vivo implantation using a reproducible model of ACL reconstruction in an athymic rat. This model can be utilized to evaluate different ...

Rupture of the anterior cruciate ligament (ACL) is one of most common ligament injuries of the knee1. Because the ruptured ACL&#8217;s is unable to heal without surgical intervention, the limitations in activities of daily living as well as participation in sports drive over 175,000 patients to undergo surgery each year2, with an estimated cost of one billion dollars annually3. Currently, either autograft or allograft tendon is used for ligament reconstruction. Though high success rates can be achieved with both autograft and allograft replacement, serious complications are associated with these reconstruction options4. Autograft tissue is associated with donor site morbidity and is limited in supply, especially in instances of re-rupture or multi-ligamentous injury. On the other hand, allograft tissue is linked with delayed graft integration, adverse inflammatory response, theoretical infectious risk, and limited supply5. Synthetic non-degradable grafts were developed in the 1970s and 1980s but were hampered by premature graft rupture, foreign body reactions, osteolysis, and synovitis6. As a result of these serious concerns, there are currently no synthetic grafts available for clinical use in the United States.
Due to these limitations with existing graft options and to recent developments in biology, engineering, and regenerative medicine, there has been great interest in a tissue engineered solution for ACL grafting. Current tissue engineering strategies employ degradable biological and synthetic materials to allow for host tissue ingrowth while avoiding the limitations associated with permanent synthetic material implantation7.
Polycaprolactone (PCL) is a biodegradable polymer that is FDA approved for a number of medical applications including adhesion barrier and wound dressing8, that has been used in a wide variety of applications including vascular, bone, cartilage, nerve, skin, and esophageal tissue engineering5,9-16. Favorable biocompatibility, relatively long in-vivo half-life, adequate mechanical strength, and high elasticity contribute to the popularity of this polymer in tissue engineering. In a rodent model of wound healing, implanted electrospun PCL was shown to be non-immunogenic and to integrate into local tissue without adverse reactions13. An SEM image of electrospun PCL is shown in Figure 1.
With current FDA regulatory standards, efficacy and safety in both small and large animal models would be required for a PCL or any other engineered ACL graft to move into clinical trials in the United States. Additionally, in vivo conditions can often augment the properties of an in vitro tissue engineered ACL graft. A rat model of autologous ACL reconstruction with flexor digitorum longus tendon has been previously described, in which the native ACL was severed, femoral and tibial tunnels were drilled, and the graft was passed and secured in place with suture17-22. In this paper, we will describe a modification of this model for the evaluation of engineered ACL replacements rather than for autograft-based reconstruction (Figure 2).
Although many animal models exist for ligament tissue engineering, the rat is advantageous compared to larger models for a number of reasons. These advantages include easier husbandry and handling, fewer ethical considerations, and reduced cost17,23. In addition, the rat model has been used extensively as a model for orthopaedic tissue regeneration, including cartilage, tendon, and bone tissue engineering24. In particular, athymic nude rats were chosen due to their lack of cell-mediated immune response25, allowing for the eventual implantation of xenogeneic donor cells in this model to further enhance the engineered graft in the future. In this methods paper, we describe the fabrication and surgical implantation of an acellular, biodegradable polymer graft in an athymic rat model of ACL reconstruction.

<table border="0" cellpadding="0" cellspacing="0" width="888">
	<tbody>
		<tr height="34">
			<td height="34" style="height:34px;width:347px;">Name of Material/ Equipment</td>
			<td style="width:147px;">Company</td>
			<td style="width:77px;">Catalog Number</td>
			<td style="width:317px;">Comments/Description</td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:347px;">Medical grade ester terminated poly (&#949;-caprolactone), granule form (MW = 110,000)</td>
			<td style="width:147px;">Lactel Absorbable Polymers</td>
			<td style="width:77px;"></td>
			<td style="width:317px;">Custom synthesized polymer to desired molecular weight</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:347px;">1,1,1,3,3,3-hexafluoro-2-propanol</td>
			<td style="width:147px;">Sigma-Aldrich</td>
			<td>105228</td>
			<td style="width:317px;">Solvent for PCL polymer</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:347px;">18G x 1 1/2&#34;bevel needle</td>
			<td style="width:147px;">BD Medical</td>
			<td>305196</td>
			<td style="width:317px;"></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:347px;">Remote Infuse/Withdraw Programmable Syringe Pump</td>
			<td style="width:147px;">Harvard Apparatus</td>
			<td style="width:77px;">702101</td>
			<td style="width:317px;"></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:347px;">VersaLaser VLS2.30 Laser Engraver</td>
			<td style="width:147px;">Microgeo USA</td>
			<td style="width:77px;">VLS2.30</td>
			<td style="width:317px;"></td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:347px;">Expanded Plasma Cleaner 115V</td>
			<td style="width:147px;">Harrick Plasma</td>
			<td style="width:77px;">PDC-001</td>
			<td style="width:317px;">Plasma etch just prior to collagen coating for surface modification</td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:347px;">PureCol&#160; Collagen Standard Solution, 3 mg/ml</td>
			<td style="width:147px;">Advanced Biomatrix</td>
			<td style="width:77px;">5015-A</td>
			<td style="width:317px;">Mix 8:1:2.5 solution of PureCol, 10x PBS, 0.1N NaOH 1:9 in 1x PBS</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:347px;">Suture, 5-0 Vicryl</td>
			<td style="width:147px;">Henry Schein</td>
			<td style="width:77px;">1086471</td>
			<td style="width:317px;"></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;">Suture, 4-0 Vicryl</td>
			<td style="width:147px;">Henry Schein</td>
			<td style="width:77px;">6540072</td>
			<td style="width:317px;"></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:347px;">Sharp-pointed Dissecting Scissors (Straight; 4.5 inch)</td>
			<td style="width:147px;">Fisher Scientific</td>
			<td style="width:77px;">8940</td>
			<td style="width:317px;"></td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:347px;">Buphrenorphine hydrochloride</td>
			<td style="width:147px;">Sigma-Aldrich</td>
			<td style="width:77px;">B9275</td>
			<td style="width:317px;">Use 0.03 mg/kg for both intra- and post-operatively for pain control</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:347px;">Ampicillin, injectable</td>
			<td style="width:147px;">Henry Schein</td>
			<td style="width:77px;">1185678</td>
			<td style="width:317px;">Use 25 mg/kg subcutaneously during the procedure</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:347px;">K-wire, 1.6 mm</td>
			<td style="width:147px;">Spectrum Surgical</td>
			<td style="width:77px;">SI040062</td>
			<td style="width:317px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:347px;">Keith Needle, Straight 1 1/2&#34;</td>
			<td style="width:147px;">Delasco Dermatology Lab &#38; Supply</td>
			<td style="width:77px;">KE-112</td>
			<td style="width:317px;"></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:347px;">Immunocal Decalcifying Solution</td>
			<td style="width:147px;">Fisher Scientific</td>
			<td>NC9491030</td>
			<td style="width:317px;"></td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:347px;">Opticryl Acrylic Resin Bone Cement (PMMA) (Monomer and polymer)</td>
			<td style="width:147px;">US Dental Depot</td>
			<td style="width:77px;">OPTICRYL 100410&#160;</td>
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		<tr height="23">
			<td height="23" style="height:23px;width:347px;">Instron Model 5564 Tensile Testing Machine</td>
			<td style="width:147px;">Instron</td>
			<td style="width:77px;">5564</td>
			<td style="width:317px;">Any comparable tensile testing apparatus is suitable</td>
		</tr>
	</tbody>
</table>

athymic rat model for evaluation of engineered anterior cruciate ligament grafts

Anterior cruciate ligament (ACL) rupture is a common ligamentous injury that often requires surgery because the ACL does not heal well without intervention. Current treatment strategies include ligament reconstruction with either autograft or allograft, which each have their associated limitations. Thus, there is interest in designing a tissue-engineered graft for use in ACL reconstruction. We describe the fabrication of an electrospun polymer graft for use in ACL tissue engineering. This polycaprolactone graft is biocompatible, biodegradable, porous, and is comprised of aligned fibers. Because an animal model is necessary to evaluate such a graft, this paper describes an intra-articular athymic rat model of ACL reconstruction that can be used to evaluate engineered grafts, including those seeded with xenogeneic cells. Representative histology and biomechanical testing results at 16 weeks postoperatively are presented, with grafts tested immediately post-implantation and contralateral native ACLs serving as controls. The present study provides a reproducible animal model with which to evaluate tissue engineered ACL grafts, and demonstrates the potential of a regenerative medicine approach to treatment of ACL rupture.

In our experience of 92 rat surgeries by a single surgeon, mean operative time from incision to completion of wound was 16.9 min, with a standard deviation of 4.7 min. At the time of sacrifice, rats weighed 356 &#177; 23 g. All rats tolerated the surgery well, and experienced no complications. Immediately after surgery, the rats were noted to bear weight on the operative extremity, but exhibited a slight limp. By one week post-operatively, all rats were ambulating with no appreciable limp. The animals all gained weight s...

Watch this Scientific Journal Video about Athymic Rat Model for Evaluation of Engineered Anterior Cruciate Ligament Grafts at JoVE.com

Athymic Rat Model for Evaluation of Engineered Anterior Cruciate Ligament Grafts

Animal models are important tools for the evaluation of tissue-engineered grafts. This paper presents the protocol for preparing an electrospun biodegradable polymer graft for use in anterior cruciate ligament tissue engineering, as well as a surgical protocol for implantation in a rat model.

Anterior cruciate ligament (ACL) rupture is a common ligamentous injury that often requires surgery because the ACL does not heal well without ...

athymic-rat-model-for-evaluation-engineered-anterior-cruciate

Research

JoVE Journal

Bioengineering

10.2K Views.  University of California Los Angeles. Animal models are important tools for the evaluation of tissue-engineered grafts. This paper presents the protocol for preparing an electrospun biodegradable polymer graft for use in anterior cruciate ligament tissue engineering, as well as a surgical protocol for implantation in a rat model.