1,25-(OH)2D3 ameliorates renal interstitial fibrosis in UUO rats through the AMPKα/mTOR pathway.

ABSTRACT

OBJECTIVE: To investigate the effects of 1,25(OH)2D3 on renal fibrosis associated with the AMP-activated protein kinase (AMPK)α/mechanistic target of rapamycin (mTOR) signalling pathway in a rat model of unilateral ureteral obstruction (UUO). METHODS: A total of 54 male Sprague Dawley rats were randomly divided into three groups sham-operation group, UUO group, and UUO plus calcitriol (3 ng/100 g) group. Renal tissue was excised for histological examination by immunohistochemistry and Western blot, and for gene expression analysis using real-time polymerase chain reaction. RESULTS: 1,25(OH)2D3 enhanced AMPKα levels, inhibited mTOR levels and slowed the development of interstitial fibrosis in kidney tissue. Compared with the UUO plus calcitriol group, UUO rats demonstrated more severe renal damage characterized by marked tubular atrophy, interstitial fibrosis and significant induction of fibrogenic transforming growth factor-ß1 and increased extra-cellular matrix proteins (α-smooth muscle actin and collagen type III), and decreased E-cadherin. CONCLUSION: Treatment with 1,25(OH)2D3 altered the AMPKα/mTOR signalling pathway to suppress excessive fibroblast activation observed in UUO rats. This may serve as a novel mechanism to ameliorate renal dysfunction and fibrotic lesions.