[Expression of connective tissue growth factor in renal interstitial fibrosis after ureteral obstruction and effects of rapamycin thereupon: experiment with rats].

OBJECTIVE: Is a common feature of progressive renal diseases regardless of the initiating insult To clarify the role of connective tissue growth factor (CTGF) in after (UUO) in renal interstitial fibrosis and effects of rapamycin (RAP) thereupon. METHODS: Eighteen Sprague-Dawley rats were randomly divided into 3 equal groups: unilateral ureteral obstruction (UUO) model group, undergoing ligation of the left ureter; RAP treatment group, undergoing ligation of the left ureter and intraperitoneal injection of RAP 0.04 mg.kg(-1).d(-1); and sham operation group. The right kidneys were taken out 7 and 14 days after the operation respectively to undergo renal pathological examination by Masson staining. Semi-quantitative RT-PCR was used to detect the mRNA expression of CTGF. Western blotting was performed to examine the protein expression of CTGF and fibronectin (FN). RESULTS: In comparison with the sham operation group, renal interstitial fibrosis was significant more expression in the 2 UUO groups, especially the UUO model group (P < 0.01). Seven and 14 days after the operation the levels of CTGF mRNA expression of the UUO model and RAP treatment groups (both P < 0.01), and the level of CTGF mRNA expression of the RAP treatment group was significantly lower than that of the UUO model group (P < 0.01), however, there was no significant difference in the level of CTGF mRNA expression between the 2 UUO groups 14 days after the operation. Seven and 14 days after the operation the levels of CTGF protein expression of the UUO model and RAP treatment groups were both significantly higher than that of the sham operation group (both P < 0.01), and the levels of CTGF protein expression of the RAP treatment group were significantly lower than that of the UUO model group (P < 0.05 and P < 0.01). The levels of FN expression 7 and 14 days after the operation of the 2 UUO groups were both significantly higher than that of the sham operation group (both P < 0.01). and the level of FN expression 7 days after of the RAP treatment group was significantly lower than that of the UUO model group (P < 0.01), however, there was no significant difference in the level of FN expression between the 2 UUO groups 14 days after the operation. CONCLUSION: The expression of CTGF mRNA and that of CTGF protein increase after UUO. Rapamycin play a protective role in the kidney by downregulating the CTGF expression and alleviating the renal interstitial fibrosis following UUO.