Effects of atorvastatin on expression of peroxisome proliferation activated receptor gamma in unilateral ureteral obstruction in rats]

OBJECTIVE: To observe the expression of peroxisome proliferation activated receptor gamma (PPARgamma) at different periods in renal interstitium and to study the effect of atorvastatin on the protein expression of PPARgamma in unilateral ureteral obstruction (UUO) in a rat model. METHODS: Forty-five female Sprague-Dawley (SD) rats were divided into three groups: the sham operation group, the model group and the atorvastatin group. The latter two groups underwent UUO and then received vehicle only or atorvastatin (10 mg.kg(-1).d(-1)) by daily gastric gavage, from three days before the UUO operation to the day of sacrifice . The sham operation rats received vehicle. Five rats of each group were sacrificed respectively at 5, 10 and 15 days after surgery. Histological changes in renal tissue were observed by hematoxylin and eosin (HE) and Masson stain. Immunohistochemistry for PPARgamma was performed in renal interstitium at each time point. RESULTS: Interstitial expansion and fibrosis in ureter obstructed kidney was prominent in the model group. Atorvastatin seemed to have ameliorated interstitial expansion and fibrosis in atorvastatin group. Detectable basic PPARgamma expression was observed in renal inner medulla of rats in sham operation group, and it was mainly concentrated in collecting tubules. In UUO rats, PPARgamma expression was found increased and extended to renal tubular epithelial cells. Increased PPARgamma expression was found on the 5th day after UUO, and significant PPARgamma expression was found on the 10 th day after UUO. The increased PPARgamma expression was found to be downregulated on the 15 th day after UUO, but still significantly increased compared with that of the model group at the same time point (all P<0.01). Atorvastatin could significantly increase the expression of PPARgamma as compared with the model group at each time point (all P<0.01). CONCLUSION: PPARgamma expression was found increased, and it appeared in renal tubular epithelial cells in UUO rats, Atorvastatin may play a protective role in the kidney by activating PPARgamma, thus alleviating renal interstitial fibrosis following UUO in rats.