To confirm the role of JNK and p38 in SP/NK-1R-mediated renal fibrosis, two inhibitors, namely, SP600125 (the JNK inhibitor) and SB203580 (the p38 inhibitor) were used to further assess whether MAPKs mediate the effects of the SP/NK-1R signaling on G2/M arrest, apoptosis and expression of profibrogenic genes. The gene discussed is MAPK8; the disease is renal fibrosis.