ABSTRACT
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.
ABSTRACT
Keratoplasty is a choice for the treatment of ocular surface diseases caused by corneal limbal stem cells (LSCs) deficiency.The application of traditional keratoplasty is limited by avaibility of donor corneas and allograft rejection.Constructruction of tissue engineering corneal epithelium provides an important and effective approach to the transplantation of cornea,because it can solve the lack of donor corneas and avoid allograft rejection following keratoplasty.However,the selection of the seed cells is crucial to corneal tissue engineering.What is more,the research of seed cells is becoming more and more widespread,just like embryonic stem cells (ESCs) and LSCs.This article summarized the selection of seed cells and the progress of tissue-engineered human corneal epithelium.