The Effect Of Oxidative Stress To TGF-β1 Expression On Renal Damage In Salt-sensitive Hypertensive Rats

Objective:To observe the effect of oxidative stress to TGF-β1 expression on renal damage of salt-sensitive hypertensive rats and investigate the mechanisms of oxidative stress on renal damage in salt-sensitive hypertension.Methods:Total of thirty male SD rats were left uninephrectomy, and twenty-five survived rats were randomly divided into three groups: control group( n=6), model group and treated group. The rats of control group were received subcutaneous injection of vegetable oil,drank distilled water. Other rats were received subcutaneous injection by desoxycorticosterone acetate(DOCA),drank high salt water(1%Na Cl).At the end of the 8th week, it is regarded as successful model that mean arterial blood pressure(MABP) of the rats increased at least five mm Hg than before.Twelve rats were randomly divided into model group(n = 6) and tempol group( n= 6).From 9 weeks to 12 weeks,rats in tempol group were intraperitoneal injected by tempol( 60mg·kg-1·d-1), and the rats of two other groups were received intraperitoneal injection by saline.Blood pressure was monitored once per week. In the 0, 4, 8 and 12 weeks, 24-hour urinary protein was as assayed.At the end of this experiment, HE staining was done in right renal tissue specimens to evaluate renal tubular histology variation. The content of malondialdehyde(MDA) were detected by thiobarbituric acid method in renal tissue homogenate of rats. The glutathione peroxidase(GSH) and superoxide dismutase(SOD) of renal tissue were determinated by colorimetric method.The expression levels of TGF-β1 and type III collagen in renal tissue were measured by western blot.Results:In the 4th week,compared with the control group, the average arterial blood pressure were increased in the model group and tempol group.In the 12 th week, The mean arterial blood pressure was significantly lower in the control group and the tempol group than in the model group.The 24-hour urine protein levels were significantly higher in model group than in control group and in tempol group.Compared with model group,the activity of SOD and GSH were significantly increased in tempol group and in control group,and content of MDA were significantly decreased.Compared with control group, rates in model group exhibited serious renal tubules and interstitial injury. Treated with tempol significantly attenuated oxidate-induced renal injuries.The expressions of renal TGF-β1and type III collagen were up-regulated in model group, and tempol were observed to inhibit the upregulation of renal TGF-β1、type III collagen in tempol group.Conclusions:Oxidative stress is involved in the occurrence and development of renal damage in salt sensitivity hypertensive, and antioxidant(tempol) can significantly relieve the damage of kidney. The pathway of TGF- β1 may be participate in kidney injury which were induced by oxidative stress.