Effects of HBO on intracellular levels of ROS and NO and their role in HBO induced HSP32 expression in spinal neurons. ROS scavenger NAC (5 mM) or NOS inhibitor L-NAME (100 μM) was added to the medium 30 min before HBO exposure. The intracellular ROS and NO were detected immediately after HBO exposure using immunofluorescence assay (A-H). The expression of HSP32 was detected by western blot 12 h after HBO exposure (I). The effects of L-NAME at higher concentrations (J). Significance compared with Air group, **p<0.01; significance compared with HBO group ††p<0.01. HBO, hyperbaric oxygen; HSP, heat shock protein; L-NAME, NG-Nitro-L-arginine methyl ester; NAC, N-Acetyl-L-cysteine; NO, nitric oxide; NOS, nitric oxide synthase; ROS, reactive oxygen species.