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。     

复方壳多糖组织工程皮肤的组织学特性

目的评价制备的复方壳多糖组织工程皮肤在组织学方面的特性，为其修复皮肤缺损创面提供实验依据。方法通过苏木精-伊红（HE）染色、高碘酸-希夫（PAS）染色、免疫组织化学染色及电镜，观察组织工程皮肤的组织学特征，包括表皮、真皮及两者的连接结构基底膜。结果制备的复方壳多糖组织工程皮肤表皮细胞增殖活跃，分层分化良好，厚约150μm，真皮层细胞生长正常，排列有序。PAS染色示真表皮间有均匀红染的条带出现，免疫组织化学染色结果显示Ⅳ型胶原、Ⅶ型胶原、层黏蛋白反应阳性，在电镜下可见角质形成细胞间大量桥粒，基底层内侧较多半桥粒，与机体皮肤结构相似。结论复方壳多糖组织工程皮肤组织结构良好，符合新型皮肤替代物在治疗皮肤缺损时的组织学要求。     

不同代次角质形成细胞构建组织工程皮肤的增殖分化能力比较

目的 比较三维条件下不同代次角质形成细胞构建的表皮形态及增殖分化情况.方法 采用不同代次角质形成细胞构建组织工程皮肤,通过苏木精-伊红(HE)和高碘酸-希夫(PAS)染色,观察各组组织工程皮肤的结构形态;并利用角蛋白CK1/CK10、CK5/CK14、细胞增殖核抗原Ki-67免疫组织化学染色,比较各组组织工程皮肤表皮的增殖分化能力.结果 不同代次角质形成细胞构建的组织工程皮肤都有明显的表皮真皮结构.1、2代较其他代次分层情况好,2代表皮层厚度明显高于其他代次(P＜0.05).加Ⅳ型胶原组的表皮真皮间黏附的紧密程度高于未加Ⅳ型胶原组,Ⅳ型胶原对表皮的厚度影响不大(P＞0.05).Ⅳ型胶原组PAS染色阴性,说明单独加Ⅳ型胶原不能形成基底膜结构.2代角质形成细胞Ki-67增殖系数接近正常皮肤,其余各代次角质形成细胞的增殖系数逐渐减少(P＜0.05).CK1/CK10、CK5/CK14在1、2代皮肤中阳性表达明显,其余代次对于两种角蛋白的表达并不明显.结论 3代以前角质形成细胞有更好的增殖分化能力,更适合作为组织工程皮肤的种子细胞.     

毛囊单位促进组织工程皮肤形成的体外实验研究

目的 通过插入分离的毛囊单位,构建带有皮肤附属器的组织工程皮肤,探讨毛囊对组织工程皮肤形成的作用.方法 将头皮分离成毛囊单位,插入由Ⅰ型鼠尾胶原、成纤维细胞和角质形成细胞构建的组织工程皮肤模型中,浸没培养1周,气-液界面培养3周.通过镜下观察、HE染色和免疫组化检测组织工程皮肤和毛囊的生长状态.结果 相对于悬浮培养的毛囊,实验组毛囊体外生长期延长,结构更完整.HE染色显示,实验组组织工程皮肤可见毛囊和皮脂腺存在.免疫组化染色显示,带有毛囊的组织工程皮肤中可见反映基底膜完整性的Laminin和Ⅳ型胶原呈线状连续分布于表皮、真皮连接处;而反应表皮成熟度的CK4和CK10/13则呈阳性分布于基底上层非角化细胞.结论 复合毛囊单位可以促进组织工程皮肤表皮组织的分化和成熟.本方法为组织工程皮肤的构建和毛囊的体外培养提供了新的思路和方法.     

应用胶原凝胶构建组织工程化皮肤的研究

目的探讨以胶原凝胶为支架材料构建组织工程化皮肤的可行性。方法体外分离、培养人皮肤表皮细胞和成纤维细胞；利用自制的胶原蛋白制成胶原凝胶作为组织工程支架材料；在成功构建人工真皮的基础上种植表皮细胞，构建复合人工皮肤；采用HE染色与免疫组织化学的方法对复合人工皮肤进行组织学检测。结果HE染色可见，构建的复合人工皮肤具有表皮和真皮双层结构；免疫组织化学染色显示，Ⅳ型胶原、纤维连接蛋白和层粘连蛋白阳性，在形态结构上与正常皮肤相似。结论培养的人表皮细胞和成纤维细胞种植于胶原凝胶支架上，气一液界面培养可构建出具有类似正常皮肤结构的组织工程化皮肤。     

用于替代皮肤刺激试验的组织工程表皮模型的构建研究

目的探讨人表皮细胞与聚碳酸脂膜构建组织工程表皮模型的方法,建立可用于皮肤刺激试验的组织工程表皮模型。方法应用组织工程方法,以聚碳酸脂膜为支架,以人皮肤角质形成细胞为细胞来源,构建组织工程表皮模型。气液面培养13 d,通过HE染色、角蛋白10(keratin 10,K10)和K13抗体、K14抗体、层粘连蛋白抗体、角化细胞交联外膜蛋白抗体、中间丝相关蛋白抗体免疫荧光染色、透射电镜观察组织工程表皮模型组织结构。采用快速渗透试验方法,SDS分别作用于培养基中添加脂质物(实验组)和未添加脂质物(对照组)的组织工程表皮模型18 h,测定组织活性减小50%所需化学物质的浓度(half maximal inhibitory concentration of a substance,IC50)值。结果 HE染色、免疫荧光染色及透射电镜观察显示,构建的组织工程表皮模型分化良好,具有与正常表皮相似的结构:基底膜、棘层、颗粒层和角化层。实验组和对照组组织工程表皮模型的IC50值分别为0.183%(6.00 mmol/L)和0.072%(2.36 mmol/L)。结论在聚碳酸酯膜上构建的组织工程表皮模型具有与正常表皮相似的组织结构,并且具有一定的屏障功能。     

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.     

应用胶原凝胶构建组织工程化皮肤的研究

目的探讨以胶原凝胶为支架材料构建组织工程化皮肤的可行性。方法体外分离、培养人皮肤表皮细胞和成纤维细胞;利用自制的胶原蛋白制成胶原凝胶作为组织工程支架材料;在成功构建人工真皮的基础上种植表皮细胞,构建复合人工皮肤;采用HE染色与免疫组织化学的方法对复合人工皮肤进行组织学检测。结果HE染色可见,构建的复合人工皮肤具有表皮和真皮双层结构;免疫组织化学染色显示,Ⅳ型胶原、纤维连接蛋白和层粘连蛋白阳性,在形态结构上与正常皮肤相似。结论培养的人表皮细胞和成纤维细胞种植于胶原凝胶支架上,气-液界面培养可构建出具有类似正常皮肤结构的组织工程化皮肤。     

人表皮干细胞的体外分离与培养

目的 探索人表皮干细胞（epidermal stem cells，ESCs）的分离方法和培养体系。方法 用Ⅳ型胶原纯化、富集ESCs，将黏附细胞（实验组）和未黏附细胞（对照组）分别接种在Ⅳ型胶原摹质（实验组为A1，对照组为A2）和3T3细胞滋养层（实验照组为B1，对照组为B2），培养体系为：低糖无钙DMEM培养基（添加10％胎牛血清、表皮生长因子10μg／L、氯化钙0．05mmol／L、氢化可的松0．8mg／L），观察细胞能否呈克隆状生长，用流式细胞仪和免疫细胞化学染色，对ECSs周期和表型进行分析。结果 实验组细胞呈克隆状生长，G0／G1期细胞和α6^briCD71 dim细胞百分率明显高于对照组，差异有统计学意义（P〈0．05），实验组角蛋白19免疫细胞化学染色呈阳性，对照组呈刚性。结论 人ESCs可通过Ⅳ型胶原快速黏附分选，并可在适当的培养体系里扩增。     

组织工程口腔黏膜固有层修复皮肤缺损的初步研究

目的探讨两种组织工程口腔黏膜固有层移植修复皮肤缺损的效果.方法分别以胶原凝胶和壳多糖-胶原凝胶为网架与体外培养的Wistar大鼠口腔黏膜成纤维细胞构建胶原凝胶口腔黏膜固有层(fibroblast-populated collagen lattice,FPCL)、壳多糖-胶原凝胶口腔黏膜固有层(fibroblast -populated chitosan collagen lattice,FPCCL),用BrdU标记其中的成纤维细胞后,移植修复同种异体大鼠背部全层皮肤圆形缺损.将36只21～25周龄Wistar大鼠分为FPCL组、FPCCL组及创口仅覆盖纱布的对照组,每组12只.术后行大体观察创面愈合情况;4、7、14和21 d 3组创面直径测量;组织学及免疫组织化学染色观察其组织修复情况.结果术后大鼠创面均无感染,创面结痂在14及17 d自然脱落,创面逐渐愈合,被新生表皮覆盖,术后21 d新生皮肤光滑,颜色与正常皮肤接近,无体毛.术后各时间点3组创面直径均逐渐变小,差异有统计学意义(P＜0.01),14 d以后,创口大小较稳定.术后7 d,FPCL组受植创面比FPCCL组受植创面和对照组创面小(P＜0.01).组织学观察:术后7 d,3组创面未完全表皮化;14、21 d,FPCL组、FPCCL组受植区完全表皮化,有钉突,对照组无明显钉突,表皮已分层,基底细胞层完整,最表面有角化物;真皮中新生胶原纤维细,含毛细血管.免疫组织化学染色显示,FPCL组、FPCCL组术后各时间点阳性成纤维细胞出现在肉芽组织的细胞密集处和新生真皮中,与新生肉芽组织共同参与了皮肤缺损的修复重建,未出现免疫排斥现象.结论口腔黏膜成纤维细胞作为修复皮肤缺损的种子细胞是可行和有效的,壳多糖胶原凝胶在限制受植区创面收缩变小方面优于单纯胶原凝胶.FPCL和FPCCL两组新生皮肤的质量优于对照组,两种组织工程口腔黏膜固有层作为皮肤缺损区永久性真皮替代物是可行和有效的.     

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.     

应用人自体血清培养人口腔黏膜上皮的实验研究

目的 研究人自体血清培养人口腔黏膜移植生长的生物学特性，为组织工程化尿道提供新材料。方法 将人自体血清培养黏膜移植于裸鼠体内，分别于移植后2、3、4、6周观察培养黏膜生长与转归，应用anti—HLA免疫荧光鉴定成活黏膜组织属性，应用抗人Ⅳ型胶原及抗人层黏蛋白为基底膜形成指标。结果 裸鼠体内移植培养黏膜成活生长分化良好，anti—HLA免疫荧光证实为移植的培养人黏膜组织；免疫组化发现移植后3周开始形成基底膜，4周形成完整的基底膜。结论 自体血清培养的人口腔黏膜可形成功能完整的上皮组织。     

角质细胞与成纤维细胞混合移植修复裸鼠全层皮肤缺损的初步报告

目的：利用组织工程原理探讨修复全层皮肤缺损的理想方式。方法：以裸鼠为动物模型,在皮肤全层缺损区域分别移植纤维蛋白胶(n=10),纤维蛋白胶角质细胞悬液（n=10）,纤维蛋白胶成纤维细胞悬液（n=10）以及纤维蛋白胶角质细胞成纤维细胞悬液（n=10）,术后每天对伤口进行大体观察,第5,7,10,14,21,35d,分别取材活检行组织学及免疫组织化学检查。结果：移植有角质细胞组（2和4组）的创面愈合快,术后10d组织学提示创面完全上皮化,抗人特异性HLA－1型抗原、抗involucrin染色和抗Ⅶ型胶原染色阳性证明新生上皮由移植的人角质细胞形成,抗involucrin染色阳性又证明角质细胞分化成熟有角质层形成,抗Laminin染色、抗Ⅶ型胶原染色阳性提示早期基底膜形成。组织学检查提示第4组新生上皮有许多类似皮钉样结构。结论：培养的角质细胞,成纤维细胞结合纤维蛋白胶移植到创面上后,可以形成复层分化良好、接近正常结构和功能的新生成肤组织。     

Reconstructed human skin produced in vitro and grafted on athymic mice

BACKGROUND: The best alternative to a split-thickness graft for the wound coverage of patients with extensive burns should be in vitro reconstructed autologous skin made of both dermis and epidermis and devoid of exogenous extracellular matrix proteins and synthetic material. We have designed such a reconstructed human skin (rHS) and present here its first in vivo grafting on athymic mice. METHODS: The rHS was made by culturing newborn or adult keratinocytes on superimposed fibrous sheets obtained after culturing human fibroblasts with ascorbic acid. Ten days after keratinocyte seeding, reconstructed skins were either cultured at the air-liquid interface or grafted on athymic mice. We present the macroscopic, histologic, and phenotypic properties of such tissues in vitro and in vivo after grafting on nude mice. RESULTS: After maturation in vitro, the reconstructed skin exhibited a well-developed human epidermis that expressed differentiated markers and basement membrane proteins. Four days after grafting, a complete take of all grafts was obtained. Histological analysis revealed that the newly generated epidermis of newborn rHS was thicker than that of adult rHS after 4 days but similar 21 days after grafting. The basement membrane components (bullous pemphigoid antigens, laminin, and type IV and VII collagens) were detected at the dermo-epidermal junction, showing a continuous line 4 days after grafting. Ultrastructural studies revealed that the basement membrane was continuous and well organized 21 days after transplantation. The macroscopic aspect of the reconstructed skin revealed a resistant, supple, and elastic tissue. Elastin staining and elastic fibers were detected as a complex network in the rHS that contributes to the good elasticity of this new reconstructed tissue. CONCLUSIONS: This new rHS model gives supple and easy to handle skins while demonstrating an adequate wound healing on mice. These results are promising for the development of this skin substitute for permanent coverage of burn wounds.     

Type IV collagen,type IV collagenase activity and ability of cell proliferation in human thyroid tumours

BACKGROUND: The processes of malignant tumour invasion and metastasis are known to include the destruction of cell stroma and vascular basement membrane. It has been suggested that type IV collagenase degrades type IV collagen, a main component of the basement membrane. METHODS: In our study, type IV collagenase activity in human thyroid tumours was measured by the Liotta method. The degree of destruction of diseased regions of thyroid tumours was immunohistochemically determined by anti-type IV collagen antibody staining. Cell proliferation in the tumours was estimated using anti-proliferating cell nuclear antigen (PCNA) and epidermal growth factor receptor (EGFR). RESULTS: T4 thyroid carcinomas with higher type IV collagenase activity and very weak type IV discontinuous immunostaining for type IV collagen of follicular basement membranes, exhibited many PCNA or EGFR positive cells. In benign tumours, normofollicular- or macrofollicular-type tumours with low type IV collagenase activity showed few PCNA and EGFR positive cells and intact type IV collagen of basement membranes, as seen in normal thyroids. Conversely, an atypical adenoma with higher type IV collagenase activity showed many PCNA and EGFR positive cells and weak type IV discontinuous immunostaining for type IV collagen, as in thyroid carcinomas. CONCLUSION: These findings suggest that staining for type IV collagen and type IV collagenase activity reflect the ability of cell proliferation, and help predict the aggressiveness of invasion and metastasis in human thyroid tumours.     

Intraspinal pigmented schwannoma with malignant progression

A case with recurrent pigmented intraspinal tumour with malignant progression is presented. The primary tumour grew around the nerve roots T9 and T10, was attached to dura and infiltrated the vertebral bone tissue. On light microscopy it was comprised of monomorphic cells with large amount of cytoplasmic pigment and many large pigmented globoid bodies. Mitoses were not observed. On electron microscopy, in addition to cytoplasmic melanosomes of regular size, macromelanosomes were numerous. The tumour cells were surrounded partially by basement membrane like material. On these bases a histological diagnosis of benign pigmented tumour of neural crest origin was suggested (a possible pigmented meningioma or pigmented schwannoma). The patient got a recurrence one year after the primary operation. Biopsy from the re-operation showed histologically the same type of tumour with more pleomorphic cells. Subsequently, the tumour grew progressively and metastases were observed in the lungs and in the skin. The patient died two years after the primary operation. The malignant progression of the tumour and other reports on similar tumours was most consistent with a diagnosis of malignant pigmented schwannoma and this was confirmed later on with immunohistochemical staining showing positive staining for basement membrane components, collagen type IV and laminin as well as a positive staining for S-100 protein. The present findings show that despite benign histological features these tumours can behave very aggressively and stress the need of more information on this type of tumour.     

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.     

Extracellular matrix in prostate adenocarcinoma: Changes in the glycoprotein component of the basement membrane

This study was designed to assess the condition of the basement membrane of archival prostate carcinoma tissue when adjacent to tumor cells of varying degrees of malignancy, using a simple staining technique. Tissue was obtained from 87 patients with untreated prostate cancer. Tissue was randomly selected from four patients from each of four Gleason grades of 2, 3, 4, and 5. Tissue was fixed in 10% formalin and routinely processed. Sections were freshly cut from paraffin blocks and slides were subjected to the periodic acid-Schiff (PAS) reaction. Gleason grades 2, 3, 4, and 5 were visualized. As the Gleason grade increased, the intensity of staining, density, and thickness of the gel-like basement membrane decreased. With the increasing Gleason grade, as seen by the PAS stain, the basement membrane glycoprotein decreased in its density and thickness with increased fragmentation, which suggested that the basement membrane would be so modified by the tumor cells to allow the tumor to spread locally. The breakdown of the basement membrane is probably a consequence of increased intratumor pressure, certain proteolytic enzymes, and increased cell motility associated with increased degree of malignancy.