摘要目的 研究缺血性脑损伤及预先电刺激小脑顶核(FNS)对前增食欲素原(prepro-orexin)及OX1受体(OX1R)的影响.方法 建立持续性大脑中动脉闭塞(MCAO)大鼠模型,分为假手术组(PO组)、FNS假手术组(FNS-PO组)、缺血组(PI组)、缺血后FNS治疗组(PI-FNS组)、预先行小脑顶核毁损,再缺血行FNS治疗组(FNL-PI-FNS组).各组均分1,3,6,12,24 h 5个亚组.采用免疫组织化学法检测Prepro-Orexin和OX1R的表达变化,逆转录-聚合酶链反应(RT-PCR)法检测OX1R mRNA的表达变化,酶联免疫法检测(RT-PCR)下丘脑及血浆中orexin-A水平的变化.结果 随着缺血时间延长,PI组Prepro-Orexin免疫反应性的平均OD值不断降低,至缺血第12小时时,降至最低.与PO组、FNS-PO组相比差异有统计学意义(P＜0.05).同时,OX1R免疫反应性的平均OD值不断增高,缺血第12小时时,达到高峰,与PO组、FNS-PO组相比差异有统计学意义(P＜0.05).PI-FNS组缺血第6小时、第12小时组与其相应PI组相比,差异有统计学意义(P＜0.05).FNL-PI-FNS组结果与PI组差异无统计学意义(P＞0.05).PO组、FNS-PO组OX1R mRNA表达相似(P＞0.05).PI组随着缺血时间延长,OX1R mRNA表达增高,缺血第24小时时,达到高峰.PI-FNS组在缺血第12小时、第24小时与其相应PI组相比,差异有统计学意义(各组P＜0.05).FNL-PI-FNS组结果与PI组差异无统计学意义(P＞0.05).此外,各组血浆orexin-A水平差异无统计学意义(P＞0.05);PI和FNL-PI-FNS组下丘脑orexin-A水平随着缺血时间延长,呈不断降低趋势.缺血第12小时时,与PO组、FNS-PO组相比,差异有统计学意义(P＜0.05).PI-FNS组与PO、FNS-PO组相比,差异无统计学意义(P＞0.05).结论 脑缺血后可以影响食欲素原系统的表达,FNS能够调节这种变化.

abstractsObjective To investigate changes in the expression of prepro-orexin and orexin receptor-1 ( OX1R) following permanent middle cerebral artery occlusion ( MCAO ) with or without preconditioning through electrical stimulation of the cerebellar fastigial nucleus (FNS). Methods Wistar rats were subjected to permanent MCAO and randomly divided into 5 groups: a sham-operated control group (PO), an FNS preconditioning + shamoperated control group (FNS-PO) , an ischemia group, an FNS preconditioning + ischemia group (FNS-PI) and a cerebellar fastigial nucleus injury + FNS preconditioning + ischemia group (FNL-FNS-PI). Each group was divided into 5 subgroups according to the time at which the animals were sacrificed after the MCAO ( 1, 3, 6, 12 and 24 h).RT-PCR was used to detect expression of OX1R mRNA, and ELISA to measure the levels of orexin-A in the hypothalamus and plasma. Results The immunoreactivity of prepro-orexin decreased significantly in the PI groups, with further decreases over time. At the 12th h after MCAO, the immunoreactivity of prepro-orexin reached a minimum.There were significant differences between the rats in the PO and FNS-PO groups. On the contrary, the immunoreactivity of OX1R increased significantly in the PI groups, with further increases continuing over time, peaking at 12 h after the MCAO. There were significant differences between the PO and FNS-PO groups. In the rats with FNS preconditioning (PI-FNS) , the decrease in prepro-orexin and the increase in OX1R were significantly inhibited compared to the PI subgroups at the 6th and 12th hour. There was no significant difference between the FNL-PIFNS group and the PI group. The expression of OX1R mRNA increased significantly in the PI group, with further increases continuing over time, peaking at 24 hours. The plasma levels of orexin-A were not significantly different among the groups, but the levels of orexin-A in the hypothalamus decreased significantly in the PI and FNL-PI-FNS groups, with further decreases continuing over time. At the 12th h after the MCAO the levels were significantly different compared with the PO and PO-FNS groups. While in the rats with FNS preconditioning (PI-FNS) , the decrease in orexin-A level was reversed and there was no significant difference compared with PO and PO-FNS groups. Conclusions The orexinergic system is altered following cerebral ischaemia. FNS preconditioning may be able to regulate these changes.