Bladder Fibrosis And Oxidative Stress In Diabetes-Induced Bladder In A Rat Model

Objective:To discuss the pathogenesis of bladder fibrosis and investigate oxidative stress in the bladder 8 weeks after diabetes induction and evaluate the effect of Tadenan on improving bladder fibrosis and oxidative stress status due to diabetes.Materials and Methods:1.To set up the model of diabetic cystopathy in Wistar rats:30 Wistar rats(3months, 200±10g)were divided into three groups:control(n=10),streptozotocin-induced diabetic group(n=10),treatment(n=10;diabetic rats were fed with Tadenan100 mg.Kg^-1.day^-1).8 weeks later,the bladders were dissected.2.Measurement of hydroxyproline using a method based on alkaline hydrolysis, Variance analysis compares the difference of results of each group.3.Measurement of the expression of TGFβ1 and bFGF by immunohistochemistry, RT-PCR and ELISA in the bladder,Variance analysis compares the difference of results of each group.4.Measurement of catalase(CAT),superoxide dismutase(SOD),mark for lipid peroxidation,maleic dialdehyde(MDA)by chemical methods and the levels of inducible nitric oxide synthase(iNOS)using immunohistochemistry.Results:1.Bodyweight and blood glucose in each group:bodyweight and blood glucose of control group,diabetic group and treatment group are 340.34±10.12g, 4.36±3.46mmol/L,240.82±10.32g,25.46±4.45mmol/L,245.76±9.87g, 25.41±4.45mmol/L,which illustrated the rats in diabetic and treatment group had successfully induced into diabetic rats.2.The content of hydroxyproline in control,diabetic and treatment group are 1.5326±0.5405μg/mg bladder weight,2.7917±1.1642μg/mg bladder weight, 1.1745±0.7043μg/mg bladder weight.There is great difference in diabetic group vs control(P＜0.05)and in treatment vs diabetic group(P＜0.05).3.Immunohistochemical results in each group:the IOD of TGF and bFGF in control, diabetic and treatment group are 3.73±2.26,4.83±3.16;48.81±5.05,58.40±7.04; 18.65±4.60,7.75±4.10.There is great difference in diabetic group vs control(P＜0.05) and in treatment group vs diabetic group(P＜0.05).4.Expression of TGF and bFGF in each group:the median expression of TGF mRNA and protein in diabetic group(0.422±0.127;21.436±1.65 pg./μgprotein)are significantly higher than that in control(0.145±0.052;7.159±1.956 pg./μgprotein) (P＜0.05),the median expression of TGF mRNA and protein in treatment group(0.281±0.066;14.641±1.938 pg./μgprotein)are significantly lower than that in diabetic group(0.422±0.127;21.436±1.65 pg./μgprotein)(P＜0.05).The median expression of bFGF mRNA and protein in diabetic group(0.489±0.096;25.968±1.648 pg./μg protein)are significantly higher than that in control(0.118±0.021;7.952±0.854 pg./μg protein)(P＜0.05),the median expression of bFGF mRNA and protein in treatment group(0.097±0.011;12.911±0.984 pg./μgprotein)are significantly lower than that in diabetic group(0.489±0.096;25.968±1.648 pg./μg protein)(P＜0.05).5.The CAT and SOD activity(11.458±1.688 U/mgprotein,7.159±2.956 U/mgprotein) significantly decreased from diabetic group compared with control group(16.099±1.767 U/mgprotein,21.436±5.645 U/mgprotein)(P＜0.05),MDA levels(15.968±1.648 nmol/mgprotein)significantly increased from diabetic group compared with control group(7.952±0.854 nmol/mgprotein)(P＜0.05), Immunohistochemical studies showed a statistically significant increased number of iNOS-positive cells in diabetic group(67.5±10.6)compared with control group(0.0±0.0)(P＜0.05).The CAT and SOD activity(14.472±1.529 U/mgprotein, 16.641±4.938 U/mgprotein)significantly increased from treatment group compared with diabetic group(11.458±1.688 U/mgprotein,7.159±2.956 U/mgprotein)(P＜0.05), MDA levels(10.911±0.984 nmol/mgprotein)significantly decreased from treatment group compared with diabetic group(15.968±1.648 nmol/mgprotein)(P＜0.05), Immunohistochemical studies showed a statistically significant decreased number of iNOS-positive cells in treatment group(13.2±5.4)compared with diabetic group(67.5±10.6)(P＜0.05).Conclusions:1.Bladder fibrosis occurred easily during diabetic cystopathy.2.Expression of TGFβ1 and bFGF were increased significantly in diabetic bladder, which maybe an important factor in diabetic cystopathy.3.Activities of CAT and SOD were decreased significantly and the level of MDA and expression of iNOS were increased significantly in diabetic bladder,which indicated oxidative stress played an important role in diabetic cystopathy.4.Tadenan could effectively slow down the process of bladder fibrosis and improve oxidative stress status due to diabetes.