[Role of nuclear factor of activated T-cells cytoplasmic 1 on vascular calcification in rats with chronic renal failure].

Objective: To explore the role of nuclear factor of activated T-cells cytoplasmic 1 (NFATc1) on vascular calcification in chronic renal failure rats. Methods: Nineteen male Sprague-Dawley (SD) rats were randomly divided into three groups: sham-operated group ( n =6), 5/6 Nephrectomy (Nx) group ( n =6), 5/6 Nx+ calcitriol group ( n =7). Vascular calcification was determined by von Kossa staining and orthocresolphthalein complexone (OCPC) method. Protein expressions of NFATc1 and runt-related transcription factor 2 (Runx2) in aortas were measured by immunohistochemistry. In vitro, vascular smooth muscle cells (VSMCs) were primarily cultured and calcification was induced by β-glycerophosphate (β-GP). These cells were then randomly divided into control group, calcification group (10 mmol/L β-GP) and cyclosporin A (CsA) intervention group (10 mmol/L β-GP+ 1 μg/ml CsA). Calcium deposition was measured by Alizarin red staining and OCPC method; alkaline phosphatase (ALP) activity was measured by enzyme-linked immunosorbent assay. RT-PCR and Western blotting were used to observe the mRNA and protein expression of VSMCs NFATc1 and Runx2 respectively. Results: Compared to that in sham-operated and 5/6 Nx group, the expression of NFATc1 was obviously up-regulated in 5/6 Nx+ calcitriol group (7.20±0.46 vs 1.52±0.77, 2.04±1.31, P <0.05). In vitro, VSMCs calcification was successfully induced by high phosphorus environment, and RT-PCR and Western blotting showed that the expressions of NFATc1 and Runx2 were up-regulated ( P <0.05). The calcification level in CsA intervention group was lower than that in calcification group [(60.86±7.95) vs (107.20±11.07) mg/g, P <0.05], and expression of Runx2 (mRNA and protein level) and ALP activity [(48.63±3.02) vs (98.75±3.46) U/g, P <0.05] decreased as well. Conclusion: NFATc1 contributes to accelerating vascular calcification in rat with chronic renal failure, the possible mechanism of which is that NFATc1 promotes VSMCs transformation to osteogenic phenotype.