Role of ERK1/2, p38 MAPK, CREB, and Nrf2 in HBO induced HSP32 expression in rat spinal neurons. p38 MAPK inhibitor (SB203580, 10 μM) or EKR1/2 inhibitor (U0126, 10 μM) were added to the medium 30 min before HBO exposure and the expression of HSP32 was detected by western blot 12 h after HBO exposure (A). Neurons were transfected with shNrf2, shCREB or vector as described in the Materials and methods section, and the effects on the expression of HSP32 were detected by western blot (B). The knockdown efficiency of shCREB (C) and siNrf2 (D) at different MOI values are presented (C, D). Significance compared with Air group, **p<0.01; significance compared with HBO group, ††p<0.01. MOI, Multiplicity of Infection.