Objective To evaluate the effect of hydrogen-rich saline on neuropathic pain in rats.Methods One hundred and twenty male Sprague-Dawley rats,weighing 200-250 g,were randomly divided into 4 groups (n =30 each) using a random number table:sham operation group (S group); hydrogen-rich saline group (H group); chronic constrictive injury (CCI) group; CCI + hydrogen-rich saline group (CH group).Neuropathic pain was induced by CCI.The animals were anesthetized with intraperitoneal 10％ chloral hydrate 300 mg/kg.The left sciatic nerve was exposed and 4 ligatures were placed on the sciatic nerve at 1 mm intervals.In H and CH groups,hydrogen-rich saline 10 ml/kg was injected intraperitoneally twice a day for 3 consecutive days starting from 1 day after CCI.The paw withdrawal threshold to mechanical stimulation with yon Frey filament (PWT) and paw withdrawal latency to thermal stimulation (PWL) were measured on the day before CCI (T0) and on 3,5 and 7 days after CCI (T1-3).The rats were sacrificed after the last measurement of pain threshold at T4.The left lumbar segments (L4-6) of the spinal cord were removed for determination of the contents of tumor necrosis factor-alpha (TNF-α),interleukin-1β (IL-1β),interleukin-6(IL-6) and high-mobility group box-1 (HMGB1) (by ELISA),and malondialdehyde (MDA) content and superoxide dismutase (SOD) and catalase (CAT) activities (using visible spectrophotometer).Results Compared with S group,PWT was significantly decreased,PWL was shortened,the contents of TNF-α,IL-1β,IL-6,HMGB1 and MDA were increased,and the activities of SOD and CAT were decreased at each time point after CCI in CCI and CH groups.Compared with CCI group,PWT was significantly increased,PWL was prolonged,the contents of TNF-α,IL-1β,IL-6,HMGB1 and MDA were decreased,and the activities of SOD and CAT were increased at all the time points after CCI in group CH.Conclusion Hydrogen-rich saline can alleviate neuropathic pain in rats via reducing the inflammatory response and lipid peroxidation response.

Aim To observe the effects of promethazine on the analgesia,hypnosis,amnesia and therapeutic index of isoflurane.Methods The experiments were designed to study promethazine on the analgesic effect of isoflurane by hot-plate test and writhing test,and to study the effect of promethazine on the sleeping time of isoflurane by the method of righting reflex,and the amnesia of isoflurane by Morris water maze,and the ED_(50),LD_(50) by sequential method in mice.Results The result of hot-plate test and writhing test indicated that promethazine could enhance the analgesic effect of isoflurane(P＜0.05 or P＜0.01);through the experiment of righting reflex, sleeping time of isoflurane in mice was extended by promethazine(P＜0.01);in Morris water maze experiment, the average latency in the combination of promethazine and isoflurane was longer than that of the promethazine group or isoflurane group(P＜0.05 or P＜0.01), while aiming to the residence time, the combination of the two was shorter than that in the third quadrant(P＜0.01 or P＜0.05),the TCPP of the group of isoflurance was more than that of the combination group;promethazine could decrease the ED_(50) of isoflurance(P＜0.01),but it did not obviously affect its LD_(50)(P＞0.05).Conclusion Promethazine can not only reinforce the effect of isoflurance on analgesia,hypnosis and amnesia, but also boost the therapeutic index of isoflurance.