高压氧后处理对神经病理性痛大鼠脊髓背角及海马P2X4受体表达的影响

Effects of hyperbaric oxygen post-conditioning on expression of P2X4 receptor in spinal dorsal horn and hippocampus of rats with neuropathic pain

目的 评价高压氧后处理对神经病理性痛大鼠脊髓背角及海马P2X4受体表达的影响.方法 雄性SD大鼠72只,8～10周龄,体重300 ～ 350 g,采用随机数字表法,将其分为3组（n=24）：假手术组（S组）、神经病理性痛组（NP组）和高压氧后处理组（H组）.采用坐骨神经慢性压迫性损伤法制备大鼠神经病理性痛模型.H组于模型制备后1d时行高压氧处理,以10 kPa/min的速率向舱内加压至2个标准大气压时,保持压力60 min,随后以10 kPa/min的速率减压至正常,1次/d,连续7d.于模型制备前1d及模型制备后1、3、7、14d时测定机械缩足反应阈和热缩足反应潜伏期,测定结束后,每组取6只大鼠,取L4-6节段脊髓及海马组织,采用免疫组化法测定P2X4受体表达.结果 与S组比较,NP组和H组MWT降低,TWL缩短,脊髓背角及海马P2X4受体表达上调（P＜0.05）;与NP组比较,H组MWT升高,TWL延长,脊髓背角及海马P2X4受体表达下调（P＜0.05）.结论 高压氧后处理通过下调脊髓背角及海马P2X4受体表达,减轻大鼠神经病理性痛.

Objective To evaluate the effects of hyperbaric oxygen post-conditioning on the expression of P2X4 receptors in the spinal dorsal horn and hippocampus of rats with neuropathic pain （NP）.Methods Seventytwo male Sprague-Dawley rats,aged 8-10 weeks,weighing 300-350 g,were randomly divided into 3 groups （n =24 each） using a random number table：sham operation group （group S）,NP group and hyperbaric oxygen postconditioning group （group H）.NP was induced by chronic constrictive injury.The rats in group H underwent hyperbaric oxygen treatment once a day for 7 consecutive days starting from 1 day after NP was successfully induced.After the rats were placed in the hyperbaric oxygen chamber,the pressure was increased at a rate of 10 kPa/min until the hyperbaric oxygen was at 2.0 atmosphere absolute,and maintained at this level for 60 min,and then the pressure was decreased at a rate of 10 kPa/min until the normal pressure was reached.The mechanical paw withdrawal threshold （MWT） and thermal paw withdrawal latency （TWL） were measured at 1 day before NP was induced and 1,3,7 and 14 days after NP was induced.After the end of measurement,6 rats were randomly chosen from each group and then sacrificed and the L4-6 segments of the spinal cord and hippocampal tissues were removed for determination of the expression of P2X4 receptors （by immunohistochemistry）.Results Compared with group S,the MWT was significantly decreased,TWL was shortened,and P2X4 receptor expression in the spinal dorsal horn and hippocampus was up-regulated in NP and H groups.Compared with group NP,the MWT was significantly increased and TWL was prolonged,and P2X4 receptor expression in the spinal dorsal horn and hippocampus was down-regulated in group H.Conclusion Hyperbaric oxygen post-conditioning mitigates NP by down-regulating the expression of P2X4 receptors in the spinal dorsal horn and hippocampus of rats.