Changes of renal vitamin D metabolic enzyme expression and calcium transporter abundance in obstructive nephropathy

The effects of urinary-tract obstruction on renal function have been clarified. However, there is little known about the change of renal vitamin D metabolic enzyme expression and vitamin D-dependent calcium transporting proteins expression in obstructive nephropathy. The male mice were subjected to unilateral ureteral obstruction (n = 10) or sham operation (n = 10). All mice were killed on day 7 after the surgical operation. Kidney sections were stained with Masson's trichrome and gene expression was analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR. The obstructed kidney exhibited interstitial fibrosis as shown by the strong collagen deposition in the interstitium. Quantitative PCR results showed the increase of 1-OHase (P < 0.001) mRNA expression and the decrease of 24-OHase (P < 0.01), CaBP-9k (P < 0.01) and CaBP-28k (P < 0.01) mRNA expression in obstructed kidney as compared to that of the Sham group. In addition, the mRNA expression of 1-OHase and CaBP-9k was significantly increased and decreased, respectively, in obstructed kidney as compared to that of the contra-lateral kidney in unilateral ureteral obstruction (UUO) mice. Together, the present finding supports the hypothesis that the ureteral obstruction leads to the alteration of renal vitamin D metabolic enzyme expression and calcium transporter abundance, which may secondarily induce the abnormality of vitamin D endocrine system and bone health.