Bradykinin stimulates proliferation and fibronectin expression in cultured rat renal mesangial cells

Objective: To investigate the direct effect of bradykinin(BK) on proliferation and fibronectin expression in cultured rat mesangial cells and whether the effects of BK and transforming growth factor-β1(TGF-β1) on fibronectin levels are synergistic.Methods: Mesangial cell proliferation was assessed by MTT assay,and fibronectin expression in mesangial cells was investigated by Western blotting.Results: In quiescent mesangial cell cultures(0.5% serum for 24 hr),BK stimulated cell proliferation in a dose dependent fashion.Both BK and TGF-β1 induced a significant increase in mesangial cell fibronectin levels.Furthermore,the effects of BK and TGF-β1 on fibronectin levels were synergistic.Conclusion: These results suggest that BK directly stimulates proliferation and fibronectin expression in cultured mesangial cells,thus promoting glomerular injury.