Effect of peroxisome proliferator-activated receptor-gamma excitomotor on the expression of nuclear factor-kappa B and apoptosis of retinal ganglion cells in rat retina with diabetes mellitus

Background As one of the most common microvascular complication of diabetes in eyes,diabetic retinopathy (DR) is one of the most important cause of blindness.Nuclear factor-kappa B (NF-κB) is involved in the occurrence and development of the disease through the activation of a series of inflammatory cytokines.Objective The present study was to investigate the effects of peroxisome proliferator-activated receptor-gamma (PPAR-γ) excitomotor,rosiglitazone,on NF-κB expression and apoptosis of the retinal ganglion cells (RGCs) in the retina with diabetes mellitus. Methods Ninety SPF male Wistar rats were randomized into normal control group,diabetic control group and rosiglitazone group.Diabetes mellitus was induced by intraperitoneal injection of 50 mg/kg streptozotocin(STZ).Then 3 mg/kg rosiglitazone was intragastricly administered once per day in the rosiglitazonegroup,and the same volume of saline solution was used at the same way in the normal control group and diabetic control group from 3 days after modeling.The rats were sacrificed and the eye cups specimen was made at 4,8 and 12 weeks after usage of drugs.Retinal histopathological examination was performed by hematine-eosin staining,and expression of NF-κB p65 protein in retina and apoptotic index(AI) of RGCs were detected by immunohistochemistry and TUNEL assay,respectively in different time points mentioned above.The use of the animals complied with the Regulations for the Administration of Affairs Concerning Experimental Animals by State and Technology Commission.Results The blood glucose level was significantly elevated at various time points in the diabetic control group and rosiglitazone group compared with normal control group (P＜0.01 ),and that of the rosiglitazone group was significantly declined in comparison to the diabetic control group (q =0.81,0.82,1.23,P＞ 0.05 ).Normal retinal structure was seen in the normal control group,and edema retinal cell and disorder of retinal layers were exhibited in the diabetic control group.Retinal structure was almost normal in the rosiglitazone group.The NF-κB p65 was expressed weakly in the retina of normal control group,but the expression of NF-κB p65 was significantly elevated in the diabetic control group and rosiglitazone group compared with the normal control group(P＜0.01 ).However,the expression of NF-κB p65(A value)was significantly decreased in the rosiglitazone group compared with diabetic control group at 8 weeks and 12 weeks( q=17.77,15.30,P＜0.01 ).There were a few apoptotic cells in rat retina of the normal control group.Compared with the normal control group,the AI of the diabetic control group and rosiglitazone group was significantly reduced(P＜0.01 ).However,the AI of RGCs in the rosiglitazone group was significantly lower than that of diabetic control group in various time points (q =19.28,27.39,49.92,P＜0.01 ). Conclusions As one of the PPAR-γexcitomotors,rosiglitazone can inhibit apoptosis of RGCs through downregulating the expression of NF-κB in rat retina with diabetes mellitus,indicating a protective effect of rosiglitazone on retina in diabetic rat. Key words: Peroxisome proliferator-activated receptor-gamma excitomotor;  Diabetic retinopathy;  Retinal ganglion cell;  Nuclear factor-κB;  Apoptosis