MAPK8 and atrial fibrillation: Western blot results showed that pretreatment with 1.0 μM NAC for 2 hours significantly blocked the decrease of total EGFR and the increase of phosphorylated EGFR, JNK, ERK, P38MAPK, c-Jun, MAPKAPK2, and HSP27 induced by treatment with 2.0 μM AF for 12 hours (Fig 8).