海马mTOR信号通路在大鼠炎性痛中的作用

Role of hippocampal mammalian target of rapamycin signaling pathway in inflammatory pain in rats

目的 评价海马哺乳动物雷帕霉素靶蛋白（mTOR）信号通路在大鼠炎性痛中的作用.方法 健康成年雄性SD大鼠60只,体重180～ 240 g,采用随机数字表法分为4组（n=6）：对照组（C组）、炎性痛组（IP组）、二甲基亚砜组（DMSO组）和mTOR抑制剂雷帕霉素组（R组）.采用左侧后肢足底皮下注射蜜蜂毒溶液50μl的方法制备炎性痛模型.C组左侧后肢足底皮下注射生理盐水;D组给予2％二甲基亚砜灌胃3d,1 ml/d,于第3天灌胃后1h时制备炎性痛模型;R组给予雷帕霉素10 mg/kg（溶于2％二甲基亚砜中）灌胃3d,1 ml/d,于第3天灌胃后1h时制备炎性痛模型.于造模后2h时,测定机械缩足反应阈（MWT）和热缩足潜伏期（TWL）.痛阈测定结束后,处死大鼠,取海马组织,采用Western blot法测定mTOR、磷酸化mTOR（p-mTOR）、核糖体S6激酶（S6K）和磷酸化S6K（p-S6K）的表达水平.结果 与C组比较,IP组和DMSO组MWT降低,TWL缩短,海马组织p-mTOR和p-S6K的表达上调（P＜0.05或0.01）,mTOR和S6K的表达差异无统计学意义,R组MWT、TWL和海马组织p-mTOR、mTOR、p-S6K和S6K的表达差异无统计学意义（P＞0.05）;与IP组比较,DMSO组MWT、TWL和海马组织p-mTOR、mTOR、p-S6K和S6K的表达差异无统计学意义（P＞0.05）,R组MWT升高,TWL延长,海马组织p-mTOR和p-S6K的表达下调（P＜0.05或0.01）,mTOR和S6K的表达差异无统计学意义（P＞0.05）.结论 海马mTOR信号通路参与了大鼠炎性痛的形成.

Objective To evaluate the role of hippocampal mammalian target of rapamycin （mTOR） signaling pathway in inflammatory pain in rats.Methods Sixty adult male Sprague-Dawley rats,weighing 180-240 g,were randomly divided into 4 groups （n=6 each） by using a random number table：control group （group C）,inflammatory pain group （group IP）,dimethyl sulfoxide （DMSO） group and rapamycin （inhibitor of mTOR） group （group R）.Inflammatory pain was produced by injection of honey bee venom 50 μl into the plantar surface of the left hindpaw.While the equal volume of normal saline was given instead in group C.In group D,2％ DMSO was injected through a gastric tube into stomach 1 ml per day lasting for 3 days,and inflammatory pain was produced at 1 h after the last injection on 3rd day.In group R,rapamycin 10 mg/kg （in 2％ DMSO） was injected through a gastric tube into stomach 1 ml per day lasting for 3 days,and inflammatory pain was produced at 1 h after the last injection on 3rd day.At 2 h after the model was established,the mechanical paw withdrawal threshold （MWT） and thermal paw withdrawal latency （TWL） were measured.Rats were sacrificed after measurement of pain threshold,and hippocampal tissues were obtained for detection of the expression of mTOR,phosphorylated mTOR （p-mTOR）,ribosomal S6 kinase （S6K） and phosphorylated S6K （p-S6K）.Results Compared to group C,the MWT was significantly decreased,TWL was shortened,the expression of p-mTOR and p-S6K was up-regulated,and no significant change was found in the expression of mTOR and S6K in IP and DMSO groups,and no significant change was found in group R in the MWT,TWL and expression of p-mTOR,mTOR,p-S6K and S6K.Compared to group IP,no significant change was found in group DMSO in the MWT,TWL and expression of p-mTOR,mTOR,p-S6K and S6K,and the MWT was significantly increased,TWL was prolonged,the expression of p-mTOR and p-S6K was down-regulated,and no significant change was found in the expression of mTOR and S6K in group R.Conclusion Hippocampal mTOR signaling pathways are involved in the development of inflammatory pain in rats.