Role of BMP-7 and TGF-β1 expression in renal tubulo-interstitial lesion of Wistar rats induced by unilateral ureteral obstruction

Objective: To explore the role of bone morphorgenetic protein-7 （BMP-7） in the renal tubulo-interstitial lesions induced by unilateral ureteral obstruction （UUO）. Methods: Sixty Wistar rats were equally and randomly divided into normal control, sham operation and UUO groups, and respectively sacrificed on the 1st, 3rd, 7th, 14th day after the time of UUO operation. The mRNA levels of BMP-7 and TGF-β1 in the renal tissues were examined by RT-PCR. The expression sites and levels of BMP-7 and TGF-β1 proteins were detected by immunohistochemistry staining. Results:Compared to control groups, the level of BMP-7 mRNA was significantly decreased, but that of TGF-β1 mRNA was significantly increased in UUO rats. Immunohistochemistry staining indicated that BMP-7 mainly expressed in the renal tubules and interstitum, rarely in the glomeruli. In UUO rats, the expression of BMP-7 protein was decreased, but that of TGF-β1 was increased in an obstruction dependent manner. Conclusion:The down- regulation of BMP-7 is observed in the early phase of fibrotic process of the renal interstitium, suggesting it may be involved in the formation and development of the tubulo-interstitial lesions.