MAPK14 and major depressive disorder: Moreover, to determine whether the p38 MAPK pathway may contribute to the activation of oxidative stress and whether p38 involved in the protective effects of NAC in depressive rats, we injected SB203580 to block p38 MAPK activity before CUMS exposure, and the behavioral results showed that SB203580 significantly ameliorate the depression-like symptoms and significantly reduced the levels of the oxidative stress products, MDA and NO, which induced by CUMS exposure.