| Objective: To observe the effect of glipizide combined with calcium dobesilate on pathological changes in retinas of diabetic model rats,and to detect the effect of the combination on protein expression of protein kinase C,hypoxia inducible factor 1alpha(HIF-1?),vascular endothelial growth factor(VEGF)in retina tissues.Methods: A total of 55 male SD rats aged six weeks were randomly allocated to normal control group with 9 rats.The rest rats were given high glucose,high-fat and intraperitoneal injection of streptozocin to make diabetic rat model.The model rats were randomly divided into diabetic model control group,gliclazide group,calcium dobesilate group,and gliclazide combined with calcium dobesilate group.Saline or corresponding drugs were continuously given for 8 weeks.After the last administration,the rats were fasting for 12 hours.Then abdominal anesthesia,abdominal aorta blood collection,rat eyeball extraction were conducted.Weights of rats in each group were determined during drug delivery.Fasting blood glucose was measured by blood glucose meter before and after administration.Colorimetric was used to determine glycosylated hemoglobin.Automatic biochemical analyzer was used to determine blood lipid,Pathological changes in retinas were observed by HE staining and microscopy.Immunohistochemical method was used to determine PKC protein in retina.Enzyme-linked immunosorbent assay for determination of vascularendothelial growth factor and HIF-1a in retinal tissue,The expression of PKC,HIF-1?and VEGF protein in retinas was detected by Western blot.Results: Compared with the normal group,the weight of diabetic rats in t he diabetic model group decreased significantly(P<0.01);the fasting blood glu cose was significantly higher(P<0.01);the content of glycosylated hemoglobin increased significantly(P<0.01);Compared with the diabetic model group,TC,TG,LDL-C and HDL-C in gliclazide group were improved in varying degree s(P<0.01).TC,TG and LDL-C in calcium dobesilate group were decreased,while HDL-C was increased,but there was no statistical difference.TC and T G in combination group decreased significantly,with statistical significance(P<0.05);the positive expression of PKC protein in the retina increased,express ion levels of vascular endothelial growth factor(VEGF)and HIF-1a in retina were significantly higher(P<0.01).Compared with the rats in diabetic model g roup,the weight of rats in the gliclazide group increased(P<0.01),the weight of rats in the combined drug group also increased significantly(P<0.01);the f asting blood glucose in gliclazide group and combination group was significantl y lower(P<0.01);the contents of TC,TG,LDL-C and HDL-C in each medic ation group were improved in varying degrees(P<0.01),and compared with si ngle medication,the changes of TC,TG,LDL-C and HDL-C in gliclazide com bined with calcium dobesilate group were significant(P<0.01 or P<0.01);the glycosylated hemoglobin content of rats in gliclazide group and combined drug group decreased in varying degrees(P <0.05 or P<0.01);HE staining showe d that each drug group improved the pathological damage of retina,and the co mbination group had the most obvious improvement;the expression of PKC pr otein in the retina in each administration group decreased in varying degrees;l evels of vascular endothelial growth factor(VEGF)and HIF-1a in retina of rat s in each drug group were significantly lower(P<0.01 or P<0.05),and the V EGF in combined drug group was significantly lower than that in single drug group(P <0.05 or P<0.01);the expression of PKC,HIF-1a and VEGF in retin a tissue of the drug-treated group was significantly decreased by WB method(P<0.05).Conclusions: Gliclazide combined with calcium dobesilate markedly impr oves the pathological damages in retinas of diabetic rats,and its mechanism m ay be related to lowering blood sugar,down-regulating the expression of PKC,HIF-1a and vascular endothelial growth factor in retinal tissue,It was most cl osely related to down-regulation of HIF-1a and VEGF expression. |
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