| Objective:To investigate the changes of glomerular podocyte and slit diaphragm and research it's pathogenesis and effect in type two diabetes;and investigate probucol's protective effects on glomerular podocyte and slit diaphragm.Methods:Thirty-six adult male SD rats were randomly divided into two groups: normal control group(ordinary diet 10 rats,N);high-glucose-high-fat diet group (high-glucose-high-fat diet,26 rats).A series of datas were evaluated such as serum lipids,serum glucose,fasting serum insulin after 8 weeks;and HOMA-IR were calculated.The 26 high-glucose-high-fat diet group were injected into tail venous with a low dose of STZ(30 mg/kg)to induce diabetes.23 rats become diabetic rats model when blood glucose was above 16.67mmol/l.Then all the rats were redivided into 3 groups:group N(10 rats,ordinary diet did not changed);group D(12 rats diabetic group);group P(11rats,diabetic group treated with intervention orally by probucol 500mg/kg/d);Group D and group P were continuously fed with high-glucose-high-fat diet,group N were fed with normal diet for eight weeks.All the animals of each group were sacrificed and then a series of datas were evaluated such as serum glucose,fasting serum insulin,serum lipids,serum creatinine,blood urine nitrogen,24 hours urine microalbumin,the ratio of kidney weight to body weight, activities of superoxide dismutase(SOD),glutathione peroxidase(GSH-PX)and concentrations of malondialdehyde(MDA)in renal cortex were measured. Immunohistochemistry was used to detect slit diaphragm protein nephrin.The levels of nephrin mRNA and podocin mRNA and CD2AP mRNA were detected by reverse transcriptasepolymerase chain reaction(RT-PCR).In addition,the ultrastructure of glomerular podocytes was observed by transmission electronic microscopy.Statistical analysis use SPSS 13.0 statistic software.Results:1.In comparison with normal control group,the high-glucose-high-fat diet rats injected with a low dose STZ increase blood glucose,HOMA-IR and serum lipids,consistent with the feature of type 2 diabetic mellitus. 2.Compared with normal control rats,the activities of SOD and GSH-PX decreased and the concentrations of MDA increased significantly in diabetic renal cortex (P＜0.05,P＜0.05,P＜0.05,respectivly).Compared with group D,the activities of SOD and GSH-PX increased significantly and the concentrations of MDA decreased markedly in group P rats renal cortex(P＜0.05,P＜0.05,P＜0.05,respectivly). Compared with normal control rats,group D and group P increase the ratio of kidney weight to body weight(P＜0.05,P＜0.05).3.Compared with normal control rats,the protein expression of nephrin,nephrin mRNA,podocin mRNA and CD2AP mRNA decreased in diabetic renal cortex (P＜0.05,P＜0.05,P＜0.05,P＜0.05,respectivly).Compared with group D,the protein expression of nephrin,nephrin mRNA,podocin mRNA and CD2AP mRNA increased in group P rats renal cortex(P＜0.05,P＜0.05,P＜0.05,P＜0.05, respectivly).4.In D group,we can observe foot process confluence and effacement in podocytes.All above changes were relieved in P group compared with D group.Conclusions:1 The SD rats fed with high-glucose-high-fat diet and injected with low dose STZ were somehow similar with Type 2 diabetes mellitus.The Type 2 diabetic rats model were successed.2.The decreased antioxidation and increased oxidative stress in kidney may injury podocyte and slit diaphragm,impair the integrity of outer layer barrier of glomerular filtration and increase urine microalbumin in diabetic rats.Probucol may maintain the structural and functional integrity of podocyte and slit diaphragm,outer layer barrier of glomerular filtration,and decrease proteinuria by augmenting the effect of renal antioxidation and inhibiting the oxidative stress in diabetic rats.3 Up to now,most literatures were limited to in vitro and animal study model.Further study,especially the evidence-based clinical study,should be designed. |
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