AIM: To investigate the effect of transplanted pigmented epithelium-derived factor(PEDF)on human umbilical cord-derived mesenchymal stem cells(hUCMSCs)in the treatment of retinitis pigmentosa in rat models.

METHODS: The hUCMSCs were isolated and cultured, hUCMSCs were transfected with PEDF recombinant lentivirus. Experimental royal college of surgeon(RCS)rats were randomly divided into 3 groups, 8 rats in each group. The experimental group was injected with PEDF-hUCMSCs subcutaneously. The hUCMSCs control group was injected with the same amount of hUCMSCs. The PBS control group was injected with the same amount of PBS. At 4 and 8wk after injection, electroretinography(ERG), the thickness of retinal outer nuclear layer(ONL)and green fluorescent protein(GFP)staining were observed. Immunofluorescence staining of retinal sections and the phagocytosis of MERTK protein were evaluated to determine phagocytosis.

RESULTS: PEDF gene carrying recombinant lentiviral vector could efficiently infect hUCMSCs. After infection, hUCMSCs were sub cultured and the lentivirus prolonged the expression in the cells of the target gene. At 8wk after transplantation, the amplitude of b-wave in ERG were significantly higher in the experimental group than in the control groups. At 4 and 8wk after transplantation, morphological changes of ONL thickness in the experimental group were significantly higher than those in the control groups(all P<0.05). At 4 and 8wk after transplantation, hUCMSCs infected by lentiviral vector carrying PEDF were found survival in the subretinal cavity by GFP staining, and the PEDF-hUCMSCs were found having phagocytosis for outer segment fragments of photorecepter cells by immunofluorescence staining. At 4 and 8wk after transplantation, the Protein band gray values in experimental group were significantly higher than that in control groups, which indicated that the expressions of MERTK protein in experimental group were also increased significantly, and the phagocytic capacity of RPE were improved.

CONCLUSION: Transplantation of pigment epithelium-derived protein modified human umbilical cord-derived mesenchymal stem cells has a protective effect on the retina of RCS rats.