Figure 4. ET-1 modulated mesangial cell proliferation and ECM through RhoA/ROCK pathway. (A) Under HG serum-free condition, mesangial cell proliferation was detected after the treatment of ET-1 (0.5 nM, 1 nM, 2 nM) for 24 h. **p<0.01, compared with 0nM. (B) Under HG serum-free condition, ECM-related proteins (Collagen IV, Fibronectin and CTGF) and RhoA on mesangial cell membrane were detected after the treatment of ET-1 (0.5 nM, 1 nM, 2 nM) for 24 h. ET-1 (1nM, 2500pg/ml) was used for the following experiments. **p<0.01, compared with 0nM. (C-F) Under HG serum-free condition, mesangial cells were treated with ET-1 (1 nM), or ET-1 (1 nM)+Y-27632 (30 μM, RhoA/ROCK inhibitor) for 24 h. The proliferation, cell apoptosis, cell cycle and ECM-related proteins were detected in ET-1 and ET-1+Y-27632 groups using MTT, flow cytometry and western blot assay. **p<0.01, compared with ET-1. Bars depict the mean ± SD. N=3.