Effect of hyperbaric oxygen on pain behavior in model rat of chronic constriction injury

Abstract

Objective To observe the effect of early use of 0.25 MPa hyperbaric oxygen (HBO) on pain behavior in model rat of neuropathic pain (NP) and explore the mechanism. Methods Fifty-four male Sprague⁃Dawley (SD) rats were randomly divided into 3 groups (18 rats per group) including sham operation, sciatic nerve ligation with chronic constriction injury (CCI) and HBO early⁃treatment groups. The rat model of neuropathic pain was established, and CCI + HBO group received 0.25 MPa HBO treatment for 60 min per day at early stage, continuing for 5 d. The changes in general state of health, the number of paw withdrawal responses, paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) were assessed at different time points after operation. Results Compared with sham-operated group, the body weight of rats in CCI group decreased significantly (t = 4.772, P = 0.000) on the 14th day; the body weight of rats in CCI + HBO group was significantly higher than that in CCI group (t = 2.411, P = 0.029). Compared with sham-operated group, reduced PWL immediately after operation (t = 28.345, P = 0.000), and more paw withdrawal responses (t = 12.541, P = 0.000) and decreased PWT (t = 4.032, P = 0.001) from the 3rd day after operation were observed in CCI group. Compared with CCI group, the number of paw withdrawal responses decreased (t = 8.077, P = 0.000), and PWT and PWL increased (t = 2.114, P = 0.049; t = 7.715, P = 0.000) in CCI + HBO group. Conclusion 0.25 MPa HBO treatment at early stage can ameliorate the mechanical and thermal hyperalgesia. HBO may provide a new convenient and effective way for the treatment of neuropathic pain in clinic.