The phosphorylation of NF-kB and MAPK signal pathway in BV2-N, BV2-MC, BV2-MR, BV2-N + LPS (determined by western blot and normalized to β-actin). Mycoplasma contamination promoted the activation of NF-kB and MAPK signal pathway. The phosphorylation of NF-kB P65, ERK, JNK and P38 were greatly increased in BV2-MC, which was similar with LPS treated BV2-N (BV2-N + LPS). (BV2-N: normal BV2 cell, BV2-MC: mycoplasma-contaminated BV2 cell, BV2-MR: mycoplasma-removed BV2-MC cell). (*P < 0.05)