[Effects of 1, 25(OH)(2);D(3); on parathyroid hormone induced transdifferentiation and TGF-β(1); expression in cultured human renal tubular epithelial cells].

AIM: To explore the effects of 1, 25(OH)(2);D(3); on parathyroid hormone (PTH) induced transdifferentiation and TGF-β(1); expression in cultured human renal tubular epithelial cells.

METHODS: HK-2 cells were cultured in DMEM/F12 medium supplemented with 50 mL/L FBS. Cells were divided into three groups. (1) CONTROL GROUP: without PTH or 1, 25(OH)(2);D(3);; (2) PTH group: 10(-10); mol/L PTH; (3) PTH and 1, 25(OH)(2);D(3); group: 10(-10); mol/L PTH and different concentrations of 1, 25(OH)(2);D(3); (10(-10);, 10(-9);, 10(-8); and 10(-7); mol/L). The gene expressions of α-SMA and TGF-β(1); were detected by semi-quantitative RT-PCR. The protein expressions of α-SMA and TGF-β(1); were detected by Western blot. Immunocytochemisty (ICC) was used to measure the expression of α-SMA in HK-2. ELISA was used to assay the level of TGF-β(1); in the supernatant.

RESULTS: The gene expressions of α-SMA and TGF-β(1); in PTH group were significantly higher than those in control group (P<0.05). In contrast, they were significantly lower in PTH and 1, 25(OH)(2);D(3); group than those in PTH group (P<0.05). Western blot results showed α-SMA could not be detected in normal HK-2 cells, which could be detected in PTH group. TGF-β(1); protein expression in PTH group was higher than that in control group. In PTH and 1, 25(OH)(2);D(3); group, α-SMA and TGF-β(1); protein expressions were significantly lower than those in PTH group (P<0.05). ICC results showed that α-SMA was hardly expressed in cells of control group. However, positive expression of α-SMA could be seen in many cells in PTH group. In PTH and 1, 25(OH)(2);D(3); group, the cells of α-SMA positive expressed were significantly less than those in PTH group (P<0.05). ELISA results showed that the level of TGF-β(1); in the supernatant of PTH group was higher than that in control group, which was also higher than that in PTH and 1, 25(OH)(2);D(3); group (P<0.05).

CONCLUSION: 1, 25(OH)(2);D(3); can attenuate PTH-induced transdifferentiation and TGF-β(1); expression in cultured human renal tubular epithelial cells.