Figure 5: MIF-induced rat PASMCs proliferation is dependent on ERK1/2 and JNK activation. Cell proliferation was demonstrated by MTT (a) and direct cell counting (b). PASMCs proliferation stimulated by MIF (100 ng/mL) was blocked by the MEK inhibitor (PD 98059, 20 μM) and JNK inhibitor (SP 600125, 20 μM), whereas the p38 MAPK inhibitor (SB 203580, 20 μM) had no effect. . versus vehicle-treated control; versus groups treated with MIF alone.