Background Corneal transplantation faces a great challenge because of the shortage of corneal donors and difficulty of human corneal endothelial cells (HCECs) regeneration in vitro.So the study on tissue engineering cornea is still a main topic.Previous research showed that mouse embryonic stem cell conditioned medium (ESC-CM) improved the proliferative capacity of HCECs in vitro,and acellular porcine corneal stroma (APCS) was a good saffold material.However,whether HECEs cultured by mouse ESC-CM can form cell sheet in vitro were rarely studied.Objective This study was to investigate the potential that HCECs cultured by mouse ESC-CM form a monolayer cell sheet.Methods The supernatant of ESC-CM was collected after mouse ES-E14 cells were cultured,and the cultured medium was centrifuged and mixed with 75％ human corneal endothelium medium (CEM)at a proportion of 1 ∶ 3 to prepare the 25％ ESC-CM system.Primary cultures of HCECs were established from explants of corneal limbal with Descemet's membrane,and the cells were identified by using reverse-transcription PCR to determine the expressions of collagen Ⅷ (Col Ⅷ) mRNA and neuron-specific enolase (NSE) mRNA in the cells.APCS was prepared by decellularization with phospholipase A2 and bicarbonate solution,and the second generation of HCECs were inoculated on the sterilized APCS at a 800/mm2 density.The morphology of the cells was observed by hematoxylin-eosin staining under the phase-contrast microscope.The expressions of zona occludens protein-1 (ZO-1)and Na+-K+-ATPase in the cell sheet were detected by immunofluorescence staining.Results The second generation of HCECs cultured with 25％ ESC-CM in vitro showed the hexagon in shape with positive expressions for Col Ⅷ mRNA and NSE mRNA.Decellularization APCS was transparent,and no corneal cells were seen,the structures of corneal collagenous fibres were regular.HCECs attached closely to APCS and formed monolayer sheet 7 days after culture on the APCS with the cell density of (2 694±143)/mm2.ZO-1 and Na+-K+-ATPase were positively expressed on the HCECs sheet.Conclusions Twenty-five percent ESC-CM promotes the proliferation and maintains the normal morphology of HCECs.APCS provide a good scoffold and microenvironment for the formation of HCEC sheet.The HCEC sheet Possesses the pump function of HCECs and is a good corneal donor for transplantation.%背景 目前角膜供体来源短缺,且体外培养的人角膜内皮细胞(HCECs)难以再生和扩增,为临床上角膜移植的开展带来了很大困难,组织工程角膜的构建仍是研究的主要课题.前期研究已证实,小鼠胚胎干细胞条件培养基(ESC-CM)能够促进体外HCECs的增生,脱细胞猪角膜基质(APCS)是较好的支架材料,但ESC-CM培养的HCECs是否能在APCS上融合成单层细胞鲜见研究. 目的 研究ESC-CM培养的HCECs在APCS上是否能够形成单层细胞. 方法 用小鼠ESC-CM培养液培养小鼠ES-E14细胞,收集培养上清液,离心后按体积比1∶3与人角膜内皮细胞培养液(CEM)混合,制备体积分数25％ ESC-CM液.取穿透角膜移植术后剩余的供体人角巩膜缘组织,采用组织块培养法用ESC-CM对HCECs进行培养和传代,采用逆转录PCR法检测HCECs中Ⅷ型胶原蛋白(ColⅧ)与神经元特异性烯醇化酶(NSE)的表达以鉴定细胞.取猪角膜,利用磷脂酶A2和碳酸氢盐溶液脱细胞法制备APCS,将第2代HCECs混合液按照800/mm2的密度种植于灭菌的APCS上进行培养,于倒置相差显微镜下观察细胞形态,采用苏木精-伊红染色法观察培养细胞的组织结构;采用免疫荧光法检测构建的HCECs单细胞片中闭锁小带蛋白-1(ZO-1)和Na+-K+-ATP酶的表达. 结果 体外培养的HCECs呈典型的六角形,内皮特异性标志物ColⅧ和NSE mRNA表达阳性.脱细胞APCS呈白色透明状,苏木精-伊红染色显示APCS中无角膜细胞,但角膜胶原纤维排列规则.第2代HCECs复水后可在APCS上生长并贴附,培养后7d融合成单层细胞片,细胞片上HCECs的细胞密度为(2 694-± 143)/mm2.构建的HCECs片中内皮细胞泵功能相关蛋白ZO-1和Na+-K+-ATP酶均呈阳性表达,呈红色荧光. 结论 25％ESC-CM可促进HCECs的生长并维持细胞的正常形态,APCS可为HCECs片的构建提供支架和较好的生存微环境.在APCS形成的HCECs单细胞片可表达HCECs泵功能,是角膜移植的良好供体.
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