Abstract:AIM: To investigate the effect of p16 protein expression on the proliferation of retinal neovascularization in oxygen-induced retinopathy(OIR).
METHODS: Totally 60 SD rats aged 7d were randomly divided into 4 groups: normal group, model group, intervention group and NS control group. Normal group was raised in a normal air feeding; model group at 75% high oxygen for 5d to establish the model of oxygen induced retinopathy; intervention group was given anti p16 methylation drug 5-aza-CdR(0.25 mg/kg)intraperitoneal injection; NS control group was given the same volume NS intraperitoneal injection. The eyes were taken from each group and the left eyes were removed for observation of retinal neovascularization by HE staining, and immunohistochemistry and immunofluorescence were taken for observations of p16 protein expression. Right retina had been performed real time-PCR to analysis p16mRNA expression.
RESULTS: The normal group were not found retinal neovascularization breaking through internal limiting mebrane. In model group and NS control group, the retinal tissue was obviously thickened, and a large number of new blood vessels were found. In the intervention group, a small amount of new blood vessels were found in the retina. The expression of p16 was low in the model group, the positive cell number was 19.52±2.67, and the number of the positive cells was 36.38±3.16 in the intervention group, the difference was statistically significant(P<0.001). Real time-PCR showed decreased expression of p16 mRNA in the model group(2-△△ct=0.14±0.01), the expression of p16 mRNA in the intervention group rats retina was significantly higher than that of NS control group rat retina, there was significant difference between two groups(2-△△ct=0.68±0.08, P<0.001).
CONCLUSION: The abnormal expression of P16 may be closely related to the proliferation of retinal neovascularization. Inhibition of p16 methylation can decrease the proliferation of retinal neovascularization.
