ABSTRACT
Objective To investigate the protective effects of intravitreal injection of pigment epithelial-derived factor (PEDF) gene-modified human umbilical cord mesenchymal stem cells (PEDF-MSCs) on the pathological changes in retinal tissue of diabetic rats.Methods hUCMSCs were isolated from human umbilical cord tissue using tissue culture methods,and transfected with lentiviral vectors at a infection multiplicity of 50.Then diabetic model in rats was successfully induced by intraperitoneal injection of streptozotocin.And the rats were divided into normal control (N),PBS treatment (D1),hUCMSCs treatment (D2) and PEDF-MSC treatment (D3) group according to different treatment methods.Three months after modeling,treatment began in D1,D2 and D3 group,but N group left untreated.Two weeks after treatment,the expression of PEDF-MSCs in the eye of rats was detected by fluorescence microscopy,and HE staining was performed to observe the changes in retinal structure and the full-thickness of the retina in each group.Results The expression of CD105,CD73,CD90 was observed,while the expression of CD34,CD45,CD11b,CD19 and HLA-DR did not present.After 2 weeks of treatment,it was in the vitreous cavity not the retina that clusters of red fluorescence appeared in D2 group with fluorescence microscope.There were clusters of green fluorescence in the vitreous cavity not in the retina of D3 group.HE staining showed that the retina had intact structure and clear layers as well as neatly arranged and stained evenly cells in N group.In D1 group,the nerve fibers layer (NFL) showed obvious edema,the blood vessels were dilated,the inner plexiform layer (IPL) were loose and the inner nuclear layer (INL) cells were disordered.In D2 group,the edema of NFL relieved.In D3 group,NFL edema was significantly alleviated,and the cells of INL and outer nuclear layer (ONL) arranged in regular.Full-thickness of retina was (103.82 ±4.15) μm in N group,(138.86 ±4.71) μm in D1 group,(131.17 ±3.89) μm in D2 group,and (112.24 ±4.22) μm in D3 group,respectively,and the differences were statistically significant (all P ＜ 0.05).Conclusion PEDF-MSCs can survive and continue to express in the vitreous cavity of diabetic rats for a long time.Meanwhile,intravitreal injection of PEDF-MSCs can ameliorate retinal edema and the retinal injury in diabetic rats.