Effect of different pressures of hyperbaric oxygen treatment on neuropathic pain in rats / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effect of different pressures of hyperbaric oxygen (HBO) treatment on neuropathic pain (NP) in rats.Methods Twenty-four healthy male Sprague-Dawley rats were randomly divided into 4 groups (n =6 each)sham operation group (group S),NP group,treatment with HBO at 2.0 atmosphere absolute group (group HBO2.0) and treatment with HBO at 2.5 atmosphere absolute group (group HBO2.5).The animals were anesthetized with intraperitoneal 5 ％ chloral hydrate 300 mg/kg.NP was induced by chronic constrictive injury.The left sciatic nerve was exposed and 4 loose ligatures were placed on the sciatic nerve at 1-mm intervals with 4-0 silk thread.After the rats were placed in the HBO chamber,the pressure was increased at a rate of 10 kPa/min until the desired pressure was reached,and then the pressure was maintained at this level for 60 min.The pressure was then decreased at a rate of 10 kPa/min until the normal pressure was reached.HBO treatment was performed once a day for 5 consecutive days starting from 1st day after operation in groups HBO2.0 and HBO2.5.While the rats were only placed in the HBO chamber and stayed for 100 min in groups S and NP.The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 0,1and 2 h after leaving the HBO chamber (T0.2).Results Compared with group S,MWT was significantly decreased and TWL was shortened in group NP (P ＜ 0.05).Compared with group NP,MWT was significantly increased and TWL prolonged at T1 during the treatment (P ＜ 0.05),while no significant change was found in MWT and TWL at T2 during the treatment in groups HBO2.0 and HBO2.5 (P ＞ 0.05).There was no significant difference in MWT and TWL at each time point during the treatment between groups HBO2.0 and HBO2.5 (P ＞ 0.05).Conclusion Treatment with different pressures of HBO can reduce NP in rats,but the change in pressure dose not affect the analgesic efficacy.