脱细胞猪小肠黏膜下层的组织相容性

目的:制备脱细胞猪小肠黏膜下层(SIS),研究其用作组织工程支架材料的组织相容性。方法:0.1%十二烷基磺酸钠(SDS)处理新鲜猪SIS 30min制备脱细胞SIS,H-E、4,6-二脒基-2-苯基吲哚(DAPI)及天狼星红染色观察脱细胞前后SIS的生物学特性,将其植入SD大鼠背部皮下,检测其组织相容性,对照组SD大鼠植入未脱细胞的正常SIS作为阳性对照。结果:脱细胞SIS呈白色、半透明的膜状物,具有良好的弹性及柔韧性;H-E、DAPI及天狼星红染色光学显微镜观察结果显示脱细胞SIS无细胞及DNA残留,组织结构保留完整,胶原纤维间孔隙率增加;皮下埋植术后全部动物存活,各时间段脱细胞SIS植入组大鼠创口周围皮肤愈合良好,无红肿、渗出等炎症反应。组织学观察脱细胞SIS植入早期结构完整;随着植入时间的延长,脱细胞SIS逐渐降解,结构松散。脱细胞SIS植片周围炎症细胞数明显少于正常SIS植入组。结论:脱细胞猪SIS植入SD大鼠体内具有良好的组织相容性,未引起明显的炎症反应,是一种理想的组织工程支架材料。     

异种脱细胞真皮替代睑板材料重建眼睑的可行性

背景：眼睑后层重建是眼睑重建的重点和难点,其中睑板替代物更是研究的焦点。异种脱细胞真皮作为一种新型的组织工程材料,在国内外烧伤整形领域,正得到广泛的研究和应用。 目的：观察异种(猪)脱细胞真皮植入兔眼睑后的组织相容性极其组织病理学变化。 方法：剥取健康小白猪全层皮肤20 cm×20 cm,制备异种(猪)脱细胞真皮基质。同时制备兔睑板全层缺损模型并植入脱细胞真皮基质,观察大体情况,并分别于第1,2,3周取移植交界处眼睑组织光镜下观察组织学的改变。 结果与结论：大体观察未见明显排斥反应及眼睑的变形;光镜下1周时可见局部炎症细胞浸润,2周时炎症细胞减少,3周时正常纤维组织长入,逐渐分割代替植入的胶原纤维,炎症反应消失。提示异种脱细胞真皮免疫原性低,并可引导新生胶原的生长,是一种良好的睑板替代物。     

异种脱细胞角膜基质囊袋移植的生物相容性研究

目的探讨脱细胞猪角膜基质移植入兔角膜囊袋后的生物学反应。方法猪角膜通过不同方式去除细胞及免疫源性成分，保留角膜组织基质的弹力纤维及胶原纤维，将其切取为直径为4mm的植片，植入兔角膜囊袋内，在不同时间点观察生物材料在角膜内生物学反应。结果材料植入兔角膜囊袋3个月，生物相容性良好，材料逐渐降解，材料内有胶原和角膜基质细胞长人。结论新型可降解角膜基质材料植入后未见兔角膜有明显的炎症反应，材料的组织相容性好，可作为组织工程角膜的支架材料。     

羊膜基质/聚丙烯复合补片的制备及其生物相容性评价

制备脱细胞羊膜基质, 运用物理方法将其复合于临床用聚丙烯补片, 以形成具有更好组织相容性的生物补片。通过细胞培养, 以聚丙烯膜为对照, 评价复合生物补片的细胞相容性;通过动物皮下植入实验, 以评价复合补片的组织相容性。结果表明, 复合补片羊膜基质表面上的成纤维细胞生长和形态均好于聚丙烯表面, 细胞增殖较快, 增殖率超过聚丙烯表面的50%。动物实验显示, 复合补片周围增生少, 无明显纤维包膜形成, 初期在植入周围有淋巴细胞等炎性细胞浸润, 随着羊膜逐渐降解, 4周时可见毛细血管新生;而对于聚丙烯材料, 植入处纤维包囊明显, 炎性情况也较严重。经羊膜基质复合的聚丙烯补片具有良好的细胞和组织相容性。     

内皮祖细胞在膀胱细胞外基质上的生长及分化

背景：传统的组织工程膀胱支架材料本身无血管结构,植入体内后面临血管化不足的问题。 目的：观察内皮祖细胞与膀胱细胞外基质的生物相容性。 方法：分离培养兔内皮祖细胞,种植于兔膀胱细胞外基质上与其复合培养。将复合生长材料植入兔背部皮下检测其组织相容性。 结果与结论：兔内皮祖细胞能够在膀胱细胞外基质表面正常黏附、生长、增殖,细胞形态良好。内皮祖细胞-膀胱细胞外基质植入兔体内后1周时,可见材料周围炎症反应明显,粘连严重,出血较多;苏木精-伊红染色可见组织中较多炎性细胞浸润,胶原及弹性纤维排列松散。植入后8周时可见材料已降解成碎细丝状,与周围组织融合生长在一起,但质地略脆,易出血;苏木精-伊红染色可见组织中已无明显炎症细胞浸润反应,胶原及弹性纤维排列紧密并且有新生血管长入其中。结果表明内皮祖细胞与膀胱细胞外基质具有良好的相容性,复合培养物与体内组织具有良好的相容性。     

脱细胞枪乌贼神经的制备及其生物相容性

背景：脱细胞哺乳动物神经有有髓纤维直径小、细胞成分不易彻底清除、复合细胞不均匀的缺点。 目的：制备脱细胞枪乌贼神经,并探讨其生物相容性。 方法：用Hasse化学萃取法制备脱细胞枪乌贼神经,观察其脱细胞的效果、管道及基底膜的完整性,用MTT法检测脱细胞枪乌贼神经与细胞相容性,用皮下植入实验检测其组织相容性。 结果与结论：制备的脱细胞枪乌贼神经细胞及髓鞘清除彻底、神经纤维膜管及基底膜保留完整,且膜管粗大。脱细胞枪乌贼神经皮下植入植入后1和2周材料周围有炎症细胞浸润。植入后4 周材料周围有薄层纤维结缔组织囊,材料内部及周围只有少量炎症细胞。结果证实,采用Hasse化学萃取法制备的脱细胞枪乌贼神经,细胞清除彻底,神经纤维膜管及基底膜保留完整,与异种细胞及组织相容性良好。     

异种松质骨支架体内移植免疫的实验研究

观察异种松质骨支架植入后宿主动态免疫应答,为进一步改进材料和临床应用提供实验依据。采用物理化学方法对异种(猪)松质骨进行处理得到猪松质骨支架,对猪松质骨进行蛋白提取,考马斯亮蓝法测定蛋白浓度,用提取的蛋白作抗原包被ELISA条板备用。将异种(猪)松质骨支架植入兔背部近头侧皮下,分别于移植后1周、2周、4周、8周、12周五个时间点作支架周围组织的组织学检查(HE)及外周血清抗体检测(ELISA)。结果:异种(猪)松质骨及松质骨支架的蛋白质浓度分别为(1.242±0.26)mg/ml和(0.024±0.004)mg/ml。异种(猪)松质骨蛋白抗原液经聚丙烯酰胺凝胶(SDS-PAGE)电泳分离后可清楚显示十条不同相对分子质量大小的蛋白条带(从15000到180000),异种(猪)松质骨支架蛋白抗原液经SDS-PAGE电泳分离后10000 Mr以上的蛋白条带消失,说明松质骨支架不含有效激发免疫反应的抗原蛋白成分。外周血中特异抗体水平在移植术后1周达最高,与处理前有明显差异(P<0.05),2~4周时逐渐降低,8~12周时维持在较低水平,与移植前无显著差异(P>0.05)。植术后1周,植入物周围组织光学显微镜下可见大量炎症细胞浸润,以淋巴细胞和单核细胞为主,2周以后炎症细胞浸润逐渐减轻,4周时未见明显炎性细胞浸润,术后12周,组织内炎性细胞罕见。异种(猪)松质骨支架不含有效激发免疫反应的抗原蛋白成分,植入后表现为一过性轻度的炎性细胞反应。     

新型多孔钽金属支架材料的生物学评价北大核心

背景:利用涂层制备技术在传统材料基体上沉积金属钽涂层,既利用了金属钽优异生物学性能又可降低成本,为金属钽器件的应用提供了一条切实可行的方向。目的:制备金属钽涂层支架材料,观察其体内外生物相容性。方法:采用常压化学气相沉积技术在多孔碳化硅基体上制备多孔金属钽涂层支架材料,进行以下实验:(1)体外实验:将骨髓间充质干细胞与多孔金属钽涂层支架材料共培养2周,MTT法检测细胞增殖;培养第5,10,15天,扫描电镜观察细胞在材料表面附着情况;(2)体内实验:在犬股骨头骨缺损处植入多孔钽材料,分别于植入后6,12周处死实验动物,将标本硬组织切片染色后,显微镜下观察多孔钽材料与周围组织的生长情况。结果与结论:(1)体外实验结果:随着培养时间的延长,骨髓间充质干细胞呈现出极其旺盛的增殖,相互排列紧密,细胞之间连接并爬行生长进入多孔钽孔隙中,细胞完全覆盖在多孔钽表面,细胞与细胞之间形成团状重叠现象;(2)体内实验结果:植入6周,材料与骨组织周围界限清晰,多孔钽孔隙中有少量骨组织爬行,有少许骨小梁长入,未附着部分可见孔隙周围空虚及缝隙,材料周围未见组织破坏及排斥反应;植入12周,可明显观察到材料与骨组织生长良好,多孔钽表面和孔隙内大量骨组织长入,材料孔隙与组织紧密连接,有大量骨小梁长入,多孔钽与骨组织融于一体;(3)结果表明:采用常压化学气相沉积技术制备的金属钽涂层支架材料具有良好的生物相容性。     

人牙髓干细胞与脱细胞猪小肠黏膜下层的生物相容性

目的 探讨体外培养的人牙髓干细胞（DPSCs）与脱细胞猪小肠黏膜下层(SIS)的生物相容性,为组织工程角膜上皮构建寻找理想的种子细胞。 方法 改良酶组织块法,培养人DPSCs并鉴定。细胞计数试剂盒（CCK-8）实验分别检测脱细胞SIS浸提液及脱细胞SIS对DPSCs增殖活性的影响。实验分组：（1）脱细胞SIS浸提液培养组为实验组,含10%胎牛血清的DMEM培养基培养组为对照组;（2）复合脱细胞SIS培养组作为实验组,非复合脱细胞SIS培养组为对照组。HE染色检测DPSCs接种于脱细胞SIS后的生长情况。 结果 成功获取DPSCs。脱细胞SIS浸提液及脱细胞SIS对DPSCs增殖无明显影响,与对照组相比差异无统计学意义（P>0.05）。DPSCs接种第3天和第7天后,能够在脱细胞SIS表面生长,支架纤维有断裂,细胞间有一定的连接。 结论 DPSCs与脱细胞SIS具有一定的生物相容性,有望用于组织工程角膜上皮的构建。     

化学去细胞尿道在大鼠皮下的埋置

背景：有研究提出了移植排斥反应的实质是受者免疫系统对供者移植物抗原的免疫应答反应。 目的：验证化学萃取去细胞处理对同种异体尿道移植抗原性的影响。 方法：取SD大鼠尿道共20根,每段长1 cm。其中10根采用化学去细胞法处理大鼠尿道的免疫原性成分,使其成为去细胞尿道;另外10根不做去细胞处理为新鲜尿道。在10只Wistar大鼠背部皮下植入去细胞尿道,另取10只大鼠背部皮下植入新鲜同种异体尿道。6周后取材行大体和组织学检查。 结果与结论：20只Wistar大鼠在皮下埋植尿道后均无自嗜肢体现象,切口愈合良好,饮食正常,无溃疡发生。6周后取材大体观察可见去细胞尿道周围有组织膜形成,而新鲜尿道未见组织膜形成。苏木精-伊红染色可见去细胞尿道逐渐被吸收,被平滑肌组织取代,并可见大小不等血管长入去细胞尿道内,部分有形成血窦的倾向;对照组尿道未见吸收,未见血管长入。提示化学去细胞尿道在大鼠体内逐渐形成类似正常尿道的组织材料,说明化学去细胞同种异体尿道移植的抗原性明显降低,可替代正常尿道海绵体组织。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

Histologic findings after in vivo placement of small intestine submucosal vascular grafts and saphenous vein grafts in the carotid artery in dogs.

A small caliber vascular graft from porcine small intestine submucosa (SIS) was implanted in a canine carotid artery (n = 24) and compared with an autogenous saphenous vein graft that was implanted in the contralateral carotid artery. In this study, four grafts were evaluated at the following times after surgery: 2, 7, 14, 28, 90, and 180 days. One SIS graft thrombosed at 2 days, two SIS and two saphenous vein grafts were thrombosed at 90 days, and one SIS and one saphenous vein graft were thrombosed at 180 days. At 2 days after implant, the luminal surface of the SIS graft was covered by a thin (30 mu) fibrin meshwork. By 14 days after surgery, endothelial cells on the fibrin meshwork were staining for FVIII-related antigen. Smooth muscle cells were observed in the new intima (fibrin meshwork) by 28 days. At 90 days, both types of graft had arterialized with an intima covered by endothelium, a smooth muscle media, and marked adventitial fibrosis. Similar histology was observed at 180 days. These results indicate that this SIS graft was similar to saphenous vein graft in the dog.     

Explant pathology study of decellularized carotid artery vascular grafts

The purpose of this study was to evaluate the morphologic findings in small-diameter freeze-dried decellularized carotid artery grafts implanted in goats as carotid artery interposition grafts for 6-7 months. Unimplanted decellularized carotid artery grafts did not contain intact cells; however, remnants of smooth muscle cells were present in the media. The extracellular matrix was well preserved. All decellularized grafts were patent at explant, without significant dimensional changes or aneurysm formation. Their luminal surfaces were lined by a thin neointima, consisting of myofibroblasts, collagen, and a discontinuous layer of endothelial cells. Histologic evidence of calcification within the explants was not observed; however, electron microscopy showed calcification of minute remnants of cell membranes. Inflammatory cells were not present in the graft wall. Host cell migration was greatest in the adventitia along the length of the graft. Migration of host cells into the media was more apparent close to the anastomoses, forming cellular nests rich in extracellular proteoglycans, whereas cell migration into areas subjacent to the lumen was minimal. Ingrowth of host blood vessels was not observed. These results demonstrate satisfactory structural and morphologic features of a decellularized carotid artery small-diameter graft implanted for up to 7 months.     

去细胞异体神经的形态结构及移植后的组织相容性

目的:为面神经缺损寻找一种理想的异体神经移植物。方法:取Wistar大鼠胫神经,经Triton X-100和脱氧胆酸钠溶液进行化学去细胞处理。将处理后的神经行组织学染色和免疫组织化学染色;并行异体移植修复面神经缺损,观察其组织相容性。结果:去细胞神经为一中空的神经基质管,其中的细胞和髓鞘成分被有效清除,神经基底膜被保留;异体移植后无明显炎症反应,无排斥和吸收反应,能引导宿主轴突和Schwann细胞增殖。结论:去细胞异体神经移植物具有良好的仿生性和组织相容性,可能用于修复面神经缺损。     

Biologic scaffold composed of skeletal muscle extracellular matrix

Biologic scaffolds prepared from the extracellular matrix (ECM) of decellularized mammalian tissues have been shown to facilitate constructive remodeling in injured tissues such as skeletal muscle, the esophagus, and lower urinary tract, among others. The ECM of every tissue has a unique composition and structure that likely has direct effects on the host response and it is plausible that ECM harvested from a given tissue would provide distinct advantages over ECM harvested from nonhomologous tissues. For example, a tissue specific muscle ECM scaffold may be more suitable for constructive remodeling of skeletal muscle than non-homologous ECM tissue sources. The present study describes an enzymatic and chemical decellularization process for isolating skeletal muscle ECM scaffolds using established decellularization criteria and characterized the structure and chemical composition of the resulting ECM. The results were compared to those from a non-muscle ECM derived from small intestine (SIS). Muscle ECM was shown to contain growth factors, glycosaminoglycans, and basement membrane structural proteins which differed from those present in SIS. Myogenic cells survived and proliferated on muscle ECM scaffolds in vitro, and when implanted in a rat abdominal wall injury model in vivo was shown to induce a constructive remodeling response associated with scaffold degradation and myogenesis in the implant area; however, the remodeling outcome did not differ from that induced by SIS by 35 days post surgery. These results suggest that superior tissue remodeling outcomes are not universally dependent upon homologous tissue derived ECM scaffold materials.     

Minimally immunogenic decellularized porcine valve provides in situ recellularization as a stentless bioprosthetic valve

Currently used bioprosthetic valves have several limitations such as calcification and functional deterioration, and revitalization through cellular ingrowth is impossible. To overcome these obstacles, we have developed a minimally immunogenic tissue-engineered valve that consists of an unfixed, decellularized porcine valve scaffold capable of being spontaneously revitalized in vivo after implantation. Porcine aortic root tissue was decellularized using detergents such as sodium lauryl sulfate and Triton X-100. The porcine valve was treated very gently and plenty of time was allowed for constituents to diffuse in and out of the matrix. In a preliminary study, a piece of decellularized porcine valve tissue was implanted into the rat subdermal space for 14 and 60 days and the structural integrity and calcification were evaluated. As an in vivo valve replacement model, the decellularized porcine valve was implanted in the pulmonary valve position in dogs and functional and histological evaluation was performed after 1, 2, and 6 months. Histological examination showed that the newly developed detergent treatment effectively removed cellular debris from the porcine aortic tissue. Decellularized porcine valve tissue implanted subdermally in rats showed minimal inflammatory cell infiltration and calcification. In the valve replacement model, spontaneous reendothelialization and repopulation of the medial cells were observed within 2 months, and good valve function without regurgitation was observed by echocardiography up to 6 months. The minimally immunogenic decellularized porcine valve proved effective in mitigating postimplant calcification and provided a suitable matrix for revitalizing prostheses through in situ recellularization, cellular ingrowth, and tissue remodeling.     

Bladder regeneration with cell-seeded small intestinal submucosa

This study was performed to determine the regenerative properties of smooth muscle cells (SMCs) and urothelial cells (UCs) seeded on small intestinal submucosa (SIS), utilizing a nude mouse model. Human bladder SMCs and UCs were seeded on SIS in a layered coculture fashion. Cell-seeded SIS grafts (1 x 1 cm(2)) were maintained in a CO(2) incubator for 14 days and subsequently folded with the seeded cells facing the lumenal side and implanted subcutaneously into the flanks of nude mice (n = 20). Unseeded SIS grafts were implanted into the contralateral flanks of the mice to serve as controls. Grafts were harvested at 4, 8, and 12 weeks after implantation. By 12 weeks, layered urothelium with a central lumen was noted with early smooth muscle bundle formation peripherally. At each time point, the regenerated SMCs stained positive for alpha-smooth muscle actin, and the UCs stained positive for cytokeratin AE1/AE3. The control group demonstrated no evidence of organized bladder regeneration. This study demonstrates the potential for cell-seeded SIS to induce organized bladder regeneration in vivo. This also provides the basis for additional work utilizing seeded SIS grafts for bladder augmentation.     

3-羟基丁酸与3-羟基己酸共聚酯的血管内生物相容性

背景：可降解聚合材料3-羟基丁酸与3-羟基己酸共聚酯(3-hydroxybutyrate-co- 3-hydroxyhexanoate, PHBHHx)具有良好的机械性能和生物可降解性。 目的：在体研究PHBHHx的血管内生物相容性。 方法：采用脱细胞羊肺动脉为支架,以PHBHHx涂层,构建复合补片,植入新西兰兔腹主动脉内,以脱细胞未涂层羊肺动脉片作为对照。分别于植入后第1,4,12周取出移植补片进行组织学、免疫荧光染色、扫描电镜和钙含量测定。 结果与结论：复合补片管腔面光滑无血栓,内膜增生适度,再细胞化完全;免疫荧光染色可见新生内膜组织中类内皮细胞呈CD31阳性反应,单层连续排列,间质细胞呈平滑肌肌动蛋白阳性反应;复合补片的钙含量明显低于未涂层羊肺动脉片。说明PHBHHx的血管内生物相容性满意,是心血管组织工程较为理想的腔内涂层材料。     

聚乳酸肋骨钉与纯钛环抱器植入动物体内后炎性反应及乳酸浓度的对比

文题释义：聚乳酸肋骨钉：可被人体吸收、无金属腐蚀性、手术操作简单、创伤小、不干扰影像学检查、避免二次手术取出等优点,但对于骨折断端不规则、粉碎性骨折的患者,可吸收肋骨钉固定往往不稳定,而且可能会造成体内乳酸浓度过高。 纯钛环抱器：纯钛金属是目前广泛使用的肋骨骨折内固定材料,其具有较好的手术操作性、组织相容性、固定的稳定性,最大限度恢复了胸廓的完整性,可有效缓解术后疼痛,改善患者呼吸,促使患者早日下床活动,降低术后并发症发生率,有效改善患者临床症状,但缺点是存在金属中毒风险、部分患者需二次手术取出、增加患者二次手术风险及费用负担,且金属材料对术后影像学检查有一定干扰,影响对骨折愈合的判断。 背景：目前胸外科肋骨骨折的内固定材料包括聚乳酸肋骨钉、纯钛环抱器,关于两者的临床对照研究较多,但其在体内的分子炎性反应缺乏相关报道。 目的：对比聚乳酸肋骨钉和纯钛环抱器植入兔体内后的炎性反应。 方法：将16只新西兰大白兔(成都达硕公司提供)分为实验组和对照组,实验组右侧胸大肌植入聚乳酸肋骨钉,对照组右侧胸大肌植入纯钛肋骨环抱器,植入后3 d、1周、2周、1个月、3个月抽取股动脉血,ELISA法检测白细胞介素1、白细胞介素6、乳酸与肿瘤坏死因子α浓度。取新西兰大白兔3只,左侧胸大肌植入聚左旋乳酸肋骨钉,右侧胸大肌植入纯钛肋骨环抱器,植入后1周、1个月、3个取包裹植入物周围肌肉组织,进行病理组织学观察。实验方案经成都大学附属医院伦理委员会批准。 结果与结论：①植入后3 d、1周、2周、1个月、3个月,两组间白细胞介素1、白细胞介素6、乳酸与肿瘤坏死因子α浓度比较差异均无显著性意义(P > 0.05);②植入后1周,环抱器组的主要病理变化为肌纤维坏死、炎细胞浸润、纤维组织增生,肋骨钉组主要病理变化为肌纤维坏死、炎细胞浸润和纤维组织增生,肌纤维坏死程度轻于环抱器组;植入后1个月,两组肌纤维坏死区域炎细胞数量均有所减少,坏死区域基本被纤维组织增生取代,其中肋骨钉组肌肉组织形态较为完整,组织损伤面积较小;植入后3个月,两组肌肉形态基本正常,只有少量炎细胞浸润;③结果表明,聚乳酸肋骨钉与纯钛环抱器在兔体内的炎性反应相当,无明显差异,并且聚乳酸肋骨钉植入后未增加兔体内的乳酸浓度。 ORCID: 0000-0002-2549-409X(程磊) 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

A multi-step method for preparation of porcine small intestinal submucosa (SIS)

Porcine small intestinal submucosa (SIS) has been widely used in repairing various tissues and organs. Despite this, some SIS products have the capacity to cause variable inflammatory responses after implantation resulting in severe adverse effects due to porcine cell existence. In this study, we described a multi-step method including mechanical disassociation, degrease, enzyme digestion, detergent treatment, freeze-drying and sterilization by irradiation for preparation of SIS. The efficacy of acellularization was evaluated by histological observation and the content of porcine immunoreceptor DAP12 gene. The change of growth factors contents within SIS accompanying with decellularization was quantitatively assessed by ELISA. Inflammatory reaction of SIS implanted subcutaneously in a rat was investigated. The histological examination revealed no remaining cells after enzyme digestion. Moreover, qPCR analysis demonstrated that the content of a porcine immunoreceptor gene DAP12 DNA in final SIS product (SISv) was only 1.05% of that in SIS samples (SISi) prepared by mechanical disassociation. Degrease with methanol/chloroform dramatically reduced the contents of VEGF, b-FGF, TGF-β, and TNF-α within SISii, but further treatment could not significantly reduced the contents of growth factors. SIS implanted into rats showed that inflammatory cells was more accumulated surrounded to SISi at 1, and 2 weeks, but reduced in SISv samples. The degree of inflammatory reaction for SISv was significantly less than that of SISi.     

In situ regeneration of skeletal muscle tissue through host cell recruitment

Standard reconstructive procedures for restoring normal function after skeletal muscle defects involve the use of existing host tissues such as muscular flaps. In many instances, this approach is not feasible and delays the rehabilitation process and restoration of tissue function. Currently, cell-based tissue engineering strategies have been used for reconstruction; however, donor tissue biopsy and ex vivo cell manipulation are required prior to implantation. The present study aimed to overcome these limitations by demonstrating mobilization of muscle cells into a target-specific site for in situ muscle regeneration. First, we investigated whether host muscle cells could be mobilized into an implanted scaffold. Poly(l-lactic acid) (PLLA) scaffolds were implanted in the tibialis anterior (TA) muscle of rats, and the retrieved scaffolds were characterized by examining host cell infiltration in the scaffolds. The host cell infiltrates, including Pax7+ cells, gradually increased with time. Second, we demonstrated that host muscle cells could be enriched by a myogenic factor released from the scaffolds. Gelatin-based scaffolds containing a myogenic factor were implanted in the TA muscle of rats, and the Pax7+ cell infiltration and newly formed muscle fibers were examined. By the second week after implantation, the Pax7+ cell infiltrates and muscle formation were significantly accelerated within the scaffolds containing insulin-like growth factor 1 (IGF-1). Our data suggest an ability of host stem cells to be recruited into the scaffolds with the capability of differentiating to muscle cells. In addition, the myogenic factor effectively promoted host cell recruitment, which resulted in accelerating muscle regeneration in situ.