Fig. 4. The effects of MAPK inhibitors on MG132-induced modulation of tPA/PAI-1 activity, protein, mRNA levels in rat primary astrocytes. Rat primary astrocytes were incubated in serum-free DMEM/F12 with 1 μM MG132 for 24 h with or without U0126 (10 μM), LY294002 (10 μM), SB203580 (10 μM), SP600125 (10 μM). (A) The activity of tPA/PAI-1 in the culture supernatant was determined by casein zymographic procedure as described. (B) The amount of PAI-1 protein secreted into culture spent media (Sup) and cell lysates (Cellular) were determined by Western blot using. β-Actin levels were measured as a loading control. (C) Expression of total cellular tPA and PAI-1 mRNA were measured by RT-PCR. GAPDH levels were measured as an internal control. All graphs represent the mean ± S.E.M. of four independent experiments (**p<0.01 versus Control, #p<0.05, ##p<0.01 versus MG132 1 μM treated group).
