Expression Of CTGF In Renal Of Diabetic Rats And Effects Of Mat

Objectives: Diabetic nephropathy(DN) is a serious chronic complication of diabetes, which has already been one of the main etiological factors of end stage of renal failure. The patients with DN have to live by dialysis or a kidney transplant at last, which results in the great financial consumption and severe individual depression. So researching on the pathogenesis, prevention and cure of DN are most important nowaday.It was indicated in many studies have showed that hyperglycemia was the primary factors of DN. It influenced many intracellular signal transduction pathway and activation various vasoactive substance, growth factors and so on which could influence hemodynamics of glomerulus. Finally, the glomerulus is sclerous. But now, it is believed from recently studies that the tubulointerstitial injury may be an important predictor of renal dysfunction in diabetic nephropathy. TGF-β1,CTGF is now considered to be one of the important driver molecules for ECM accumulation in the pathogenesis of diverse forms renal fibrosis including glomerulosclerosis in diabetic nephropathy, and may constitute a more specific target for futuramic anti-fibrosis therapies. It is very important to keep the function of podocyte. TGF-β1 is a important profibrogenic cytokine in the pathogenesis of diabetic nephropathy. It can influence the formation of extracellular matrix (ECM), which includes inducing synthesis of various matrix proteins, inhibiting expression of ECM degradation enzyme, disturbing synthesis and decomposition of ECM, and leading to excessive accumulation of ECM, which result in glomerulosclerosis at last.It was found in the recent research that CTGF played a key role in the occurrence and development of diabetic nephropathy. CTGF is the downstream medium of transforming growth factor-β1(TGF-β1), but CTGF does not involve in the resisting proliferation and inflammation function of TGF-β1, and only involve in accelerating cell matrix synthesis function of TGF-β1.CTGF can induce mesangial cells and other renal resident cells producing ECM by autocrine and paracrine, thereafter accelerate the glomerular hypertrophy and glomerulosclerosis inevitably.In the present study, the expressions of TGF-β1,FN,α-SMA,typeⅣcollagen and CTGF were observed and the interrelationship between these factors and development of renal lesion were analysed in the renal tissues of experimental diabetic rats. In addition, in order to provide theoretical basis for the prevention and treatment of DN,the possible mechanism of protecting renal function of mat was also investigated. Methods: 48 healthy male Wistar rats were randomly divided to 3 groups: normal control group(A),diabetic group(B) and Mat diabetic group(C). The rats of group B and C received a single intraperitoneal injection of STZ(dissolved in 0.1 mol/l citrate buffer pH4.5) at a dose of 55mg/kg WT and the rats of group A only received an injection of the same volume of sodium citrate. The diabetic model was considered to be successful when the blood glucose was 16.7mmol/l and urinary glucose(+++)-(++++) after 48hours of STZ injection. The rats of group C were treated with Mat 50mg?kg-1?d-1and the rats of group A and B were treated with the same volume of tap water. All rats were allowed free access to food and water during the experiment, whereas insulin and other hypoglycrmic drugs were not supplied. At 4 and 8 weeks after the onset of diabetes, ratio of kidney to body weight,creatinine clearanc rate, blood glucose(BG), serum creatinine(Scr), urinary creatinine(Ucr), 24-hours urinary protein, blood urea nitrogen(BUN) were measured and calculated, then eight rats were sacrificed for each group respectively. The renal cortical tissues were obtained and used for light microscope. The expression values of TGF-β1,FN,α-SMA,typeⅣcollagen,CTGF and TGF-β1mRNA in renal cortex were measured with immunohistochemical method and ELISA.Results:1. biochemical indexes: At week 4 and week 8, 24-hours urinary protein,KW/BW,blood glucose,Ccr,urea nitrogen were higher in group B than in group A(P<0.01), while, there was no significant difference between group C and group B(P>0.05). There was no statistical difference of blood glucose between the rats of group C and of group B(P>0.05). 24-hours urinary protein ,KW/BW,Ccr ,BUN were lower in group C than in group B(P<0.01).2. Renal pathological examination: At week 4 and week 8,there were no renal pathological changes in group A rats. In diabetic rats of group B, light microscopy showed that PAS-positive area of glomeruli was increased. The abnormal changes were alleviated in group C.3. Immunohistochemistry: The expressions of TGF-β1,FN,α-SMA,typeⅣcollagen,CTGF in group A were farthing. At week 4 and week 8, The expressions of TGF-β1,FN,α-SMA,typeⅣcollagen,CTGF in renal cortex in group B were higher than that of group A(p<0.0l),at the same time the expression in group C were lower than that group B (p<0.01, p<0.05).4. ELISA: At week 4 and week 8, the levels of urinary TGF-β1mRNA were higher in group B than in group A(P<0.01). At the same time, the levels of urinary TGF-β1mRNA were lower in group C than in group B(P<0.01).Conclusions: 1. Expressions of TGF-β1,FN,α-SMA,typeⅣcollagen and CTGF were up-regulated in renal cortex of diabetic rats. 2 Mat shows protective effects on diabetic kidney by normalizing the up-regulated TGF-β1,FN,α-SMA,typeⅣcollagen and CTGF in diabetic kidney. Mat decreased the levels of urinary TGF-β1mRNA. 3. Mat decreased the excreting of urinary protein, alleviate kidney hypertropathy index and renal pathological examination.