| Objective To observe changes in podocytes and Nephrin protein of kidney pathologicalchanges of diabetic rats and the effects of podocyte, nephrin protein expression of renaltissue and excretion and the changes of renal structure and function in diabetic rats afterIntervention of hydrochloride Benazepril,initially investigate renal protective effect andpossible mechanisms of benazepril.Method Healthy male Sprague-Dawley (SD) rats were were randomly divided intonormal control (NC) and experimental groups. diabetic rat model of experimentalgroup was established by a single intraperitoneal injection of streptozotocin (STZ);Afterthe modeling, the experimental group were randomly divided into control of diabetesmellitus (DM) group and benazeprill intervention (DT) group, the DT group was givenbenazepril hydrochloride10mg/kg-1·d-1, suspension by gavage.NC and DM groups wasgiven the same amount saline by using stomach tube in the corresponding time. At theend of the4th week, fasting blood glucose (FBG), glycosylated hemorglobin A1c(HbA1c), triglyceride (TG), total cholesterol (TC), urinary albumin(UALB), urinarycreatinine(Ucr),urinary retinol binding-protein(URBP)and urinary nephrin.Rats werekilled and left kidney specimens to calculate the renal hypertrophy index (BM/KM),observe the changes in kidney tissue morphology and ultrastructure of podocytes bylight microscope and electron microscopy,detect the changes of renal nephrine proteinlevels and messenger RNA (mRNA) expression levels using immunohistochemistry and reverse transcription polymerase chain reaction(RT-PCR).Results1. The levels of FBG and HbA1C in group DM and group DT were significantly higherthan that in group NC (all P<0.01), however, there were no statistical differencesbetween group DM and group DT (all P>0.05).2. TC, TG level increased significantly in group DM and group DT when comparedwith group NC (all P<0.05). No statistical differences were found between groupDM and group DT (all P>0.05).3. At the end of the forth week, urinary ALB/Cr,urine RBP/Cr, urine nephrin/Crand renal hypertrophy index of the DM group and DT group were significantlyhigher than the NC group(P <0.05);and index value of DT group were lower thanthe DM group, there were significant difference (P<0.05);what,s more,there was apositive correlation among urine nephrin/Cr, urinary ALB/Cr, urine RBP/Cr andrenal hypertrophy index.4. Via semiquantitative RT-PCR detection, nephrin protein mRNA expression of renalcortex podocyte of group DM and group DT were lower than that in group NC (allP<0.05),but, nephrin protein mRNA expression of group DT significantly higherthan the group DM,there was statistical differences（P<0.05）.5. By the unaided eye, kidney bulk of the group DM were significantly augmented incomparison with group NC,and the colour of kidney deepened, under the profile, therenal cortex and medulla were less clear,at the same time, the renal cortex wereincrassated. At high magnification, shape and structure of renal glomeruli of kidneytissue of the NC group were normal by HE staining;however, glomerular basementmembrane were incrassated，mesangial cell and renal tubular cells were hyperplastic,hypertrophy, cytoplasmic increase, cell nuclear staining deepened,and renalpathology of group DT were to make better than group DM.Compare to group NC, mean glomerular cross-sectional area(MGA) and mean glomerular volume(MGV)of group DM and group DT were significantly higher (P <0.05),in comparison withgroup DM,the index above were significantly decreased (P<0.05).6. Immunohistochemical results showed that nephrin protein specifically expressed inthe podocytes of the glomerular basement membrane,also had a small amount ofexpression on tubular, compared with group NC, the group DM and group DTnephrin expression was significantly reduced, there were statistically difference(P<0.05), but the amount of nephrin protein of group DT was more than groupDM, there were statistically difference (P<0.05).7. In the forth week, under the transmission electron microscope, glomerular basementmembrane(GBM) of the group NC,thickness was uniform, the podocytes neat,uniform density, no significant foot process (FP) fusion and shedding. However,inthe group DM,thickness of GBM is uneven, structure fuzzy, foot process fusionextensive,reduced and undermined, mesangial cells in mesangial area swell,hyperplasia and the mesangial matrix incrassation;In the group DT, GBMincrassation was not marked,ultrastructure of GBM was relatively regular, a smallquantity of foot process fusion, mesangial cells in mesangial area hyperplasia wasslight.Conclusion Hydrochloride benazepril had a significant protective effect on the kidneyof diabetic rats, and this protective effect is independent of the hypoglycemic,lipid-lowering effects, its mechanism may be partly through the increase of nephrinmRNA expression and reducing nephrin loss so as to maintain podocyte structure,molecular composition, and prevent the loss of podocytes to reduce urinary proteinexcretion. |
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