Effects of platelet-derived growth factor-BB on expression of plasminogen activator inhibitor-1 in cultured rat mesangial cells

Objective: To investigate the effects of platelet-derived growth factor-BB (PDGF-BB) on the expression of plasminogen activator inhibitor-1 (PAI-1) in cultured rat mesangial cells. Methods: The cultured rat mesangial cells were seeded at a density of 3×105 cells in cell culture bottle and stimulated with medium containing different concentrations of PDGF-BB (0,5,10 ng/ml) for different time (0,12,24,48 h). The activity of PAI-1 in culture supernatants was determined by spectrophotoetric methods. The cultured rat mesangial cells were stimulated by 0,5,10 ng/ml PDGF-BB for 24 h and 10 ng/ml PDGF-BB for 0,12,24,48 h; the expression of PAI-1 mRNA in mesangial cells was assayed by semi-quantitative RT-PCR. Results: Stimulated by 0,5,10 ng/ml PDGF-BB for 24 h,the expression of PAI-1 mRNA/GAPDH mRNA of mesangial cells were 0. 296,0. 428,0. 542,respectively. Stimulated by 10 ng/ml PDGF-BB for 0,12,24,48 h,the expression of PAI-1 mRNA/GAPDH mRNA were 0. 156,0. 345,0. 493,0. 597, respectively. PDGF-BB significantly increased the expression of PAI-1 mRNA of rat mesangial cells in a dose- and time-dependent manner. The activity of PAI-1 increased significantly after PDGF-BB addition in a dose-dependent manner and reached the maximum at 24 h and then decreased at 48 h. Conclusion; PDGF-BB can up-regulate the expression of PAI-1 mRNA in cultured rat mesangial cells and increase the activity of PAI-1 in culture supernatants. This study suggests that PDGF-BB may contribute to glomerular sclerosis by inhibiting the degradation of extracellular matrix.