体外构建复合皮移植后对大鼠创面愈合的影响

目的：观察角质形成细胞和成纤维细胞与无细胞异种真皮基质构成的复合皮移植于全层皮肤缺损创面后的效果,寻找一种新的创面覆盖物。方法：54只SD大鼠作背部全层皮肤缺损创面后分为A、B、C三组,分别以A型复合皮（角质形成细胞＋成纤维细胞＋无细胞异种真皮基质）、B型复合皮（角质形成细胞＋无细胞异种真皮基质）和普通敷料进行移植,术后定期观察创面愈合情况并进行创面收缩率的计算,同时切取创面组织进行组织学检测。结果：三组中,A组的创面愈合及外观情况最好;A组创面收缩率明显低于B、C两组（P（0．05）;组织学检测提示A组复合皮上皮分化充分,胶原增生有序,表皮一真皮连接结构重建明显,未见明显的急性期免疫排斥反应。结论：角质形成细胞和成纤维细胞与无细胞异种真皮基质构成的复合皮移植后能改善创面愈合质量,是一种较理想的、可探索的皮肤替代物。     

纤维蛋白凝胶移植培养口腔黏膜细胞的研究

目的 为培养上皮细胞寻找良好的移植载体.方法 用含自体血清培养基培养人口腔黏膜角质细胞,实验组细胞置于纤维蛋白凝胶中,对照组细胞置于DMEM:F12细胞培养液中,将悬液细胞以1×106个/ml浓度分别移植于裸鼠皮下和创面,于移植后1、2、3、4、6周取材,分别行苏木素-伊红染色及冰冻切片抗人HLA-Ⅰ免疫荧光染色及抗人Ⅳ型胶原及抗人层黏蛋白免疫组织化学检查.结果 皮下移植时,凝胶组角质细胞逐步增殖分化形成较大上皮管腔(4.62×103个/cm2),组织有多量血管形成(5.72×103个/cm2),对照组中上皮管腔(1.76×103 个/cm2)及血管数量少(0.88×103 个/cm2),两者差异有统计学意义(P＜0.01),管腔上皮抗人-HLA免疫荧光阳性;实验组创面愈合平均时间为11 d,愈合处皮肤粗糙、角化,抗人-HLA免疫荧光强阳性,免疫组织化学染色示基底膜形成完整,对照组愈合时间为18.5 d,愈合创面凹陷、光滑无角化,抗人-HLA免疫荧光弱阳性,两组创面愈合时间差异有统计学意义(P＜0.05).结论 纤维蛋白凝胶可促进移植黏膜上皮细胞的增殖分化并形成功能完备的上皮组织,是上皮细胞移植的良好载体.     

利用组织工程的方法预制含双面表皮的游离皮瓣

目的　探讨利用组织扩张器和培养的角质上皮细胞预制含双面表皮的游离皮瓣的可行性。　方法　在 10只大鼠的右下腹腹壁下动静脉皮瓣下各埋置一 10 ml容积的扩张器 ,7天后将体外培养的 10× 10 6同系鼠角质上皮细胞用 1ml纤维蛋白胶 ( fibrin glue)制成悬液后接种到扩张器与包囊之间的间隙 ,大体及组织学观察移植的角质上皮细胞是否能将扩张器外纤维包囊上皮化以形成一含双面表皮的皮瓣。皮瓣预制成功后 ,以腹壁下动静脉连同一段股动静脉为蒂行游离移植覆盖颊部洞穿性缺损。　结果　大体观察及组织学证明培养的角质上皮细胞纤维蛋白胶悬液移植后可以将扩张器的纤维包囊上皮化。　结论　利用组织工程的方法可以预制含双面表皮的皮瓣。     

自体表皮细胞悬液移植修复全层皮肤缺损创面的动物实验研究

目的探讨自体表皮细胞悬液移植技术用于全层皮肤缺损创面修复的适宜密度。方法取健康清洁级成年SD大鼠40只,雌雄不限,体质量210~230 g;根据细胞移植密度不同,随机分为高、中、低细胞密度及空白组(分别为A、B、C、D组,n=10)。取大鼠背部皮肤培养表皮细胞,并制作大鼠全层皮肤缺损创面抗挛缩模型。其中A、B、C组分别将0.2 mL密度为1×10~6、1×10~5、1×10~4个/cm~2的自体表皮细胞悬液移植至创面处,D组给予等量限制性角质形成细胞无血清培养基;取成年Wistar大鼠背部皮肤制备同种异体皮,覆盖各组创面。术后观察大鼠存活情况,于术后7、14、21 d大体观察同种异体皮成活、脱落及创面愈合情况,同种异体皮脱落后计算创面愈合率;21 d时取材行组织学及免疫组织化学染色,观察创面修复情况。结果术后大鼠均存活至实验完成。各组大鼠同种异体皮随时间延长逐渐成活,干燥并开始脱痂;至21 d同种异体皮基本脱落后A、B组创面可见成片上皮,C组创面可见少量菲薄上皮,D组创面无上皮形成。术后21 d同种异体皮脱落后,A、B、C、D组创面愈合率分别为62.9%±9.6%、64.2%±9.1%、38.5%±5.7%、22.7%±5.5%,A、B组创面愈合率显著高于C、D组(P0.05),C组高于D组(P0.05),A、B组间比较差异无统计学意义(P0.05)。组织学观察示,A、B、C组愈合的创面上皮层可见鳞状上皮细胞,A、B组表皮分层明显,C组表皮层薄、可见炎性细胞浸润,D组为肉芽组织。免疫组织化学染色观察示,A、B、C组表皮-真皮连接层Ⅳ型胶原和Ⅶ型胶原表达呈阳性,D组无表皮层呈阴性;A、B组Ⅳ、Ⅶ型胶原表达阳性细胞百分比显著高于C组(P0.05),A、B组间比较差异无统计学意义(P0.05)。结论自体表皮细胞悬液移植技术在大鼠全层皮肤缺损创面修复中可重构皮肤,1.0×10~5个/mL为创面修复的适宜移植密度。     

胎鼠表皮干细胞的分离培养及毛囊再生研究

目的：分离培养胎鼠的表皮干细胞及毛囊乳头层细胞，通过动物模型观察两者复合移植后，上皮形成及毛囊的再生情况。方法：采用IV型胶原分离培养胎鼠表皮干细胞，检测β1整合素及角蛋白15的表达水平，测定其细胞周期及克隆形成率（以角质细胞为对照）；分离培养毛囊乳头层细胞，并接种在纤维蛋白胶中，与表皮干细胞膜片复合形成全层皮肤等同物，移植在裸鼠全层皮肤缺损创面作为实验组，同时将胎鼠成纤维细胞替代乳头层细胞作为对照组，8－10周后观察创面及囊的组织学变化。结果：胎鼠表皮干细胞表达高水平的β1整合素及角蛋白15；细胞周期分析显示，G1期细胞百分率为94．9％，S期为3．5％，提示为慢循环细胞周期；角质细胞的G1期细胞有百分率为74．1％，S期为17．5％；表皮干细胞的克隆形成率为15．3％，明显高于对照组的6．7％；裸鼠创面愈合后8－10周，实验组可见新生毛囊形成，对照组未见到此现象。结论：能初步实现对胎鼠表皮干细胞的体外分离培养；在毛囊乳头层细胞的诱导下，胎鼠表皮干细胞可参与形成新的毛囊结构。     

利用毛囊干细胞和成纤维细胞重建全层皮肤的研究

目的建立利用毛囊干细胞和成纤维细胞进行全层皮肤重建的实验方法.方法取美容手术切取的头皮组织,K19免疫荧光染色定位毛囊干细胞,消化、分离、体外培养,以胶原-成纤维细胞聚合物为基质,采用气-液界面对第2代毛囊干细胞立体培养14 d,建立全层皮肤培养模型,并行组织学及K1免疫荧光染色观察.结果K19免疫荧光染色定位毛囊干细胞存在于毛囊外根鞘处,与成纤维细胞联合体外气-液界面立体培养14 d,获得的皮肤类似物,可见真皮基底膜形成,表皮多层上皮有序、多角形排列,上层细胞出现角化,真皮部成纤维细胞均匀分布于胶原基质中,角质细胞形成分化特异标志物K1染色阳性.结论毛囊外根鞘处的毛囊干细胞具有高增殖能力并向表皮细胞分化,可成功利用毛囊干细胞和成纤维细胞进行皮肤重建,为临床应用奠定基础.     

角质形成细胞源TGF-β_1对成纤维细胞的作用

目的研究正常角质形成细胞分泌的TGF-β1对正常成纤维细胞生物学行为的影响。方法采用免疫组化方法检测角质形成细胞分泌TGF-β1,以不同浓度TGF-β1抗体阻断角质形成细胞条件培养液中的TGF-β1,观察阻断前后角质形成细胞条件培养液对正常成纤维细胞增殖,胶原分泌的影响。结果细胞玻片可见大量染色阳性角质形成细胞,经TGF-β1抗体阻断后的角质形成细胞条件培养液,对成纤维细胞的促增殖作用明显减弱,胶原分泌减少。结论正常角质形成细胞分泌大量TGF-β1,可促进成纤维细胞增殖,促进胶原分泌。     

角质形成细胞源TGF-β1对成纤维细胞的作用

目的研究正常角质形成细胞分泌的TGF-β1对正常成纤维细胞生物学行为的影响。方法采用免疫组化方法检测角质形成细胞分泌TGF-β1，以不同浓度TGF-β1抗体阻断角质形成细胞条件培养液中的TGF-β1，观察阻断前后角质形成细胞条件培养液对正常成纤维细胞增殖，胶原分泌的影响。结果细胞玻片可见大量染色阳性角质形成细胞，经TGF-β1抗体阻断后的角质形成细胞条件培养液，对成纤维细胞的促增殖作用明显减弱，胶原分泌减少。结论正常角质形成细胞分泌大量TGF-β1，可促进成纤维细胞增殖，促进胶原分泌。     

体外构建皮肤基底膜的组织学特征

目的观察制备的组织工程皮肤基底膜的组织学特征。方法取门诊正常儿童包皮环切术之包皮，采用胰蛋白酶胶原酶顺序消化得到角质形成细胞（KC）和成纤维细胞（Fb）悬液。制备复方壳多糖组织工程皮肤，浸没培养3d后，继续行气液界面培养。将培养7、10、15d的复方壳多糖组织工程皮肤用中性甲醛溶液固定后石蜡包埋、切片，行HE及高碘酸-雪夫（PAS）染色，并用免疫组织化学染色法观察基底膜的重要成分：Ⅳ型胶原、Ⅶ型胶原及层黏连蛋白（LN）的存在情况。结果HE染色可见培养的组织工程皮肤表皮结构分化良好，大致可分为基底层、棘层和角质层，各层均有数量不等的扁平梭形细胞。PAS染色显示真皮表皮间有一均匀红染的条带。免疫组织化学染色结果显示，Ⅳ型胶原、Ⅶ型胶原及LN呈阳性表达。结论复方壳多糖组织工程皮肤基底膜构建良好。     

组织工程人口腔黏膜的制备及异体移植的临床应用

目的观察自行制备的复层组织工程人口腔黏膜移植后生长情况.方法取3月龄患儿唇裂术中切取的多余口腔黏膜组织,分离成纤维细胞与上皮细胞,分别接种于聚乳酸/聚羟基乙酸共聚物(polylactic/glycolic acid copolymer,PLGA)胶原复合膜上培养,后将其移至气液面进行复合,制成复层组织工程口腔黏膜.7例行口腔内良性肿瘤切除后遗留黏膜缺损的患者,缺损范围为1.8 cm×1.6 cm～3.2 cm×2.6 cm.采用组织工程口腔黏膜修复,术后观察其生长情况.1例志愿者在移植术后18和30 d分别取移植部位黏膜行组织学观察.结果制备的组织工程口腔黏膜生长良好,具有上皮层和上皮下层双层结构,之间为PLGA膜;上皮层5～6层细胞,角蛋白染色阳性,上皮下层3～7层细胞,角蛋白染色阴性.7例患者移植修复术后10 d,组织工程口腔黏膜与创面生长良好,颜色较正常黏膜深;18 d后仍可辨出移植区与正常黏膜;30 d后无法区别界限,创面均Ⅰ期愈合,无明显瘢痕组织.组织学观察:18 d创面上皮层及下方肉芽组织生长良好,毛细血管增生有上皮钉突形成,成纤维细胞卵圆形;30 d胶原化更明显,移植区结构与周边正常组织相似.结论应用组织工程口腔黏膜异体移植修复后,黏膜生长良好,但愈合组织上皮的来源还需进一步研究.     

In vivo cultured skin composed of two-layer collagen sponges with preconfluent cells.

Although various kinds of cultured skin substitutes have been developed, it takes several weeks to produce them before grafting. In their previous study, the authors succeeded in producing cultured skin easily in a short period of time by layering two collagen sponges. In the current study, to shorten this period even further, they grafted the cell-preconfluent artificial skin immediately after seeding the cells. They used two collagen sponges with different pore sizes and crosslink densities. They seeded 1,000,000 cells per square centimeter of fibroblasts and 1,000,000 cells per square centimeter of keratinocytes on the respective collagen sponges and grafted them on a full-thickness, excised wound on the back of severe combined immunodeficient mice. Two weeks after grafting, epithelium and dermislike tissue were formed. They then decreased the number of keratinocytes and grafted them. Four weeks after grafting, at seeding densities of 50,000 to 1,000,000 cells per square centimeter of keratinocytes, the preconfluent artificial skin took histologically, and human type IV and type VII collagen were stained immunohistochemically. This cell-preconfluent artificial skin composed of two-layer collagen sponges seems promising for widespread clinical use.     

Locomotion of human skin keratinocytes on polystyrene, fibrin, and collagen substrata and its modification by cell-to-cell contacts

Epithelial wound repair assures the recovery of the epithelial barrier after wounding. During wound healing epithelial cells migrate to cover the wound surface. The presented experiments were carried out to compare the migration of human keratinocytes from primary and secondary culture on polystyrene, collagen, and fibrin glue used in clinical techniques. The images of migrating keratinocytes were recorded and analyzed using computer-aided methods. The results show that the character of the substrate strongly affects the speed and turning behavior of keratinocytes locomoting over it. The highest motile activity of human skin keratinocytes was found on fibrin glue substratum. It was found that locomotion of freely moving isolated cells was much faster than that of cell sheets. The autologous keratinocytes cultured in vitro were applied with fibrin glue to cover trophic wounds. The transplantation of human autologous keratinocyte suspension in fibrin glue upon long-lasting trophic wounds appeared to induce rapid and permanent wound healing.     

血管内皮细胞和成纤维细胞混合移植对人工真皮血管化的影响

目的观察同种血管内皮细胞和成纤维细胞移植对人工真皮血管化的促进作用。方法在27只Wistar大鼠背部造成2．5 cm×2．5 cm全层皮肤缺损创面(2处／只),将其分为血管内皮细胞组:将血管内皮细胞混入0．5 ml纤维蛋白胶中,按1．0×105／cm2的密度均匀喷洒于移植床;混合组:将血管内皮细胞和成纤维细胞混入等量纤维蛋白胶后,同前密度喷洒于移植床;对照组:按同样方法喷洒等量纤维蛋白胶。随后各组移植人工真皮,每组9只大鼠18处创面。于移植后5、10 d切取移植的真皮及周围组织行HE、血管内皮生长因子(VEGF)、Masson和墨汁灌注染色,观察新生血管生长情况。于移植后5 d行伊文思蓝灌注,以分光光度计定量检测法测定微血管形成情况。结果移植后5 d,HE、VEGF、Masson和墨汁灌注染色均可见各组移植床有新生血管长入。HE染色见血管内皮细胞组、混合组新生血管数量分别为(14．2±3．6)、(12．1±2．5)条,较对照组[(3．9±1．6)条]明显增多(P<0．05)。移植后10 d,人工真皮内及移植床均有微血管形成,且胶原组织的合成增加。移植后5 d,经伊文思蓝灌注,收集并检测血管内皮细胞组、混合组真皮组织溶出的上清液,吸光度值分别为0．167±0．058、0．155±0．046,均高于对照组的0．066±0．024(P<0．05)。结论同种血管内皮细胞和成纤维细胞移植可促进创面愈合过程中的血管新生,加速人工真皮移植后血管化过程,促进类真皮组织的成熟。     

The role of fibroblasts in dermal vascularization and remodeling of reconstructed human skin after transplantation onto the nude mouse.

The vascularization and the dermal remodeling of two different types of human skin reconstructed "in vitro" and grafted onto the nude mouse were studied. They were composed of human keratinocytes grown either on a human acellular deepidermized dermis (DED), or on a lattice composed of human fibroblasts embedded in bovine type I collagen, a living dermal equivalent (LDE). At different stages after grafting, the transplants were harvested and processed for an immunohistological study with species-specific and non-species-specific antibodies. At one month after grafting, the two types of grafted dermis contained blood vessels whose vascular basement membranes were labeled with a mouse-specific anti-type IV collagen antibody. With an antibody specific for human type IV collagen, a constant labeling of the vascular basement membrane was only observed in the LDE containing fibroblasts. In the DED, a constant association of the mouse endothelial cells with human type IV collagen was observed at early stages after grafting. At later stages, the human type IV collagen progressively disappeared. On the other hand, the dermal-epidermal junction underneath the human epidermis contained human type IV collagen in the two types of reconstructed skin. Labeling with the species-specific antibodies directed against human or murine type I collagen showed that the ratio murine type I collagen versus human type I collagen increased with time, suggesting that the DED is progressively invaded by mouse fibroblasts that produce the mouse collagen. On the other hand, in the LDE, the preexisting bovine type I collagen became progressively undetectable while both human type I collagen and elastic fibers were deposited by numerous human fibroblasts. Mouse type I collagen was not detected. Altogether, these observations made by grafting human skin reconstructed "in vitro" onto the nude mouse should be interesting for evaluating the usefulness of grafting a dermal substrate together with the epidermal sheet in the treatment of burns.     

023 Development of Tissue Engineering Skin Based on Acellular Dermal Matrix

Aim: In tissue engineering of the skin, the selection of a scaffold or a matrix in which a cultured cells grow is quite important. We have developed a tissue engineering skin composed of human keratinocytes and fibroblasts on an acellular allogenic dermal matrix (ADM), derived from cryopreserved human skin. Methods: ADM was prepared from cryopreserved split‐thickness human skin by treating with Dispase and Triton X‐100. The tissue engineering skin were produced by seeding human keratinocytes and fibroblasts on ADM. Several days after seeding, the tissue engineering skin was exposed to an air‐liquid interface for another 7 days. Then, the histological structure of the skin and the production of growth factors by the skin were investigated. Results: The produced ADM was found to be completely acellular with remaining structure of the basement membrane components, such as type IV collagen and laminin. The developed tissue engineering skin had stratified keratinocytes on the surface of the ADM migrating fibroblasts in the dermal collagen structure, resembling to the normal skin appearance. It was found that several important growth factors in wound healing process, such as TGF‐α, TGF‐β and VEGF, were produced by the tissue engineering skin. Conclusions: It was suggested that ADM is suitable for a scaffold in tissue engineering of the skin.     

Culture of keratinocytes for transplantation without the need of feeder layer cells

Patients with large burn wounds have a limited amount of healthy donor skin. An alternative for the autologous skin graft is transplantation with autologous keratinocytes. Conventionally, the keratinocytes are cultured with mouse feeder layer cells in medium containing fetal calf serum (FCS) to obtain sufficient numbers of cells. These xenobiotic materials can be a potential risk for the patient. The aim of the present study was to investigate if keratinocytes could be expanded in culture without the need of a feeder layer and FCS. Keratinocytes were cultured on tissue culture plastic with or without collagen type IV coating in medium containing Ultroser G (serum substitute) and keratinocyte growth factor (KGF). An in vitro skin equivalent model was used to examine the capacity of these cells to form an epidermis. Keratinocytes in different passages (P2, P4, and P6) and freshly isolated cells were studied. Keratinocytes grown on collagen type IV were able to form an epidermis at higher passage numbers than cells grown in the absence of collagen type IV (P4 and P2, respectively). In both cases the reconstructed epidermis showed an increased expression of Ki-67, SKALP, involucrin, and keratin 17 compared to normal skin. Only 50,000 keratinocytes grown on collagen type IV in P4 were needed to form 1 cm2 epidermis, whereas 150,000 of freshly isolated keratinocytes were necessary. Using this culture technique sufficient numbers of keratinocytes, isolated from 1 cm2 skin, were obtained to cover 400 cm2 of wound surface in 2 weeks. The results show that keratinocytes can be cultured without the need of a fibroblast feeder layer and FCS and that these cells are still able to create a fully differentiated epidermis. This culture technique can be a valuable tool for the treatment of burn wounds and further development of tissue engineered skin.     

The efficacy of collagen dermis membrane and fibrin on cultured epidermal graft using an athymic mouse model

A human skin substitute consisting of human cultured keratinocytes, collagen dermis, and fibrin was evaluated in athymic mice. Eighty athymic mice were divided randomly into four groups. A 1.5x1.5-cm full-thickness wound defect was created on the back of each athymic mouse under anesthesia. These wounds were covered by sheets of cultured epidermal graft (group A), cultured epidermal graft with collagen dermis and fibrin (group B), cultured epidermal graft with collagen dermis (group C), or cultured epidermal graft with fibrin (group D). The grafts were secured and kept moist by specially designed saline gauze chambers. The take rates of the cultured graft with more than 50% of the wound covered were 65%, 15%, 50%, and 45% respectively. Group B had a significantly lower graft take rate, however the difference was not significant among groups A, C, and D. Light microscopy of biopsies of the grafted sites at 12 days showed complete epithelialization. The incidence of discharge from wound beds in groups A, B, C, and D was 0%, 15%, 15%, and 10% respectively. The results suggest that cultured cells are best grafted directly onto the wound bed or in combination with either a thin layer of collagen or fibrin but not both because the collagen dermal membrane and the fibrin together may impose too great a diffusion barrier for the cultured cell graft to become vascularized.