ABSTRACT
BackgroundLimbal stem cell deficiency usually leads to blindness, and traditional therapy is limited. Recent research demonstrated that bone mesenchymal stem cells ( BMSCs ) and human amniotic epithelial cells(AECs) could differentiate into many kinds of cells including corneal epithelial cells, but the outcome and effect of these cells on corneal stem cell deficiency are still unclear. ObjectiveThis study aimed to observe and compare the effects of rabbit BMSCs and human AECs transplantation for rabbit limbal stem cell deficiency. Methods Eighteen clean New Zealand rabbits were randomly divided into the amniotic stroma(AS) group, rabbit BMSCs group and human AECs group with 6 rabbits for each group. Limbal stem cell deficiency models were established by putting a piece of filter paper that had been soaked in a NaOH solution at the corneal center. Rabbit BMSCs were isolated and purified by density gradient centrifugation combined with the attachment culture method, and human AECs were collected by a sequential trypsin digestion technique,and the third generation rabbit BMSCs and the first generation human AECs were identified with RT-PCR. After that,cells were inoculated onto the denuded AS and grafted to the corneal surface of the experimental animals. Twenty-eight days after cell transplantation, the therapeutic effects were evaluated based on the corneal neovascularization and opacity scores. Corneal histopathological examination and immunohistochemistry were performed to evaluate and compare the effectiveness among AS,rabbit BMSCs and human AECs on corneal stem cell deficiency. The procedure complied with the Regulations for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission. ResultsThe third generation of rabbit BMSCs grew well after 12 hours, and the first generation of human AECs formed a membrane-like monolayer after 48 hours of incubation on AS. Immunohistochemistry staining showed that, 28 days after transplantation, the surface cells of the cornea were positive for cytokeratin 3 in both the rabbit BMSCs group and human AECs group.Compared with the AS group,the corneal neovascularization and opacity grades were significantly decreased in the rabbit BMSCs group( Z=-2. 983, P =0. 003 ; Z =-2. 844, P =0. 004 ) and human AECs group ( Z =-2. 817, P =0. 005 ; Z =-2.041, P =0. 041 ). Histopathological analysis exhibited that stratified corneal epithelial-like cells formed on the corneal stroms 28 days after grafting and no signs of goblet cells and neovascularization were found. Less inflammatory cells and regular collagen fiber could be seen in the rabbit BMSCs group and human AECs group. In addition,clinical observation also revealed that the corneas were much clearer in the rabbit BMSCs group than the human A ECs group( Z =-2. 091 , P=0. 037 ), but the corneal neovascularization score was similar between them (Z = -0. 267,P=-0. 789). ConclusionsRabbit BMSCs and human AECs can differentiate into corneal epithelial-like cells onthedamagedcornealsurfaceandfurtherdemonstrateremarkableinhibitoryeffectsoncornealneovascularization and inflammatory cells. The more dominant and prominent effect is the role played by rabbit BMSCsin the improvement of corneal transparency.