直推督脉对孤独症谱系障碍模型鼠PVN区催产素神经元及认知功能的影响

Effects of straight pushing the Du meridian on the oxytocin neurons in the PVN region and the cognitive function of autism spectrum disorder model rats

目的观察直推督脉对孤独症谱系障碍(autism spectrum disorder,ASD)模型鼠室旁核(paraventricular nucleus,PVN)区催产素(oxytocin,OXT)神经元活性及认知功能的影响,探讨直推督脉对ASD的作用及潜在机制。方法采用腹腔注射丙戊酸钠的方法构建ASD模型。随机取7只孕12.5 d的SD大鼠腹腔注射丙戊酸钠,3只腹腔注射生理盐水。孕鼠产仔后第21天,剔除雌性幼鼠,将剩余雄性幼鼠分为空白组、模型组、直推督脉组、药物注射组,每组5只。空白组、模型组给予腹腔注射同等剂量生理盐水;直推督脉组予以直推督脉的干预方式,20 min/次,一日2次,并予以腹腔注射同等剂量生理盐水;药物注射组以每日0.1 mg/kg的剂量腹腔注射OXT,以上干预均连续14 d。第35天进行高架十字迷宫实验、Morris水迷宫实验以判断其焦虑情绪和认知能力;通过免疫荧光染色法标记PVN区OXT与c-Fos蛋白、海马区OXT与催产素受体(oxytocin receptor,OXTR);Western blot法检测海马区OXTR蛋白表达水平;ELISA法检测幼鼠海马区与下丘脑中的OXT含量。结果与空白组相比,模型组开放臂活动时间缩短、开放臂进入次数减少(P<0.01);逃避潜伏期增加、平台所在区域活动路程减少(P<0.05,P<0.01);PVN区OXT神经元与c-Fos阳性表达、海马区OXT与OXTR结合的阳性表达、海马区OXTR蛋白表达均减少(P<0.01);下丘脑与海马区OXT含量下降(P<0.01)。与模型组相比,直推督脉组、药物注射组的开放臂活动时间增长、开放臂进入次数增加(P<0.05,P<0.01);逃避潜伏期缩短、平台所在区域活动路程增加(P<0.05,P<0.01);PVN区OXT神经元与c-Fos阳性表达、海马区OXT与OXTR结合的阳性表达、海马区OXTR的蛋白表达水平均增加(P<0.01);下丘脑、海马区OXT含量上升(P<0.01)。结论直推督脉可以改善ASD模型鼠的认知功能,其机制可能与PVN区OXT神经元被激活,OXT水平升高,从而增加其与海马区OXTR结合相关。

Objective To observe the effects of straight pushing the Du meridian(SPDM)on the activity of oxytocin(OXT)neurons in the paraventricular nucleus(PVN)region and the cognitive function of autism spectrum disorder(ASD)model rats,and to explore the effects and potential mechanism of SPDM on ASD.Methods The ASD model was established by intraperitoneal injection of sodium valproate.Seven SD rats at 12.5 days of pregnancy were randomly selected and sodium valproate was then injected into the abdominal cavity,while three other rats were injected with physiological saline into the abdominal cavity.On the 21st day after birth,female young rats were excluded and the remaining male young rats were divided into blank group,model group,SPDM group,and drug injection group,with five rats in each group.The blank group and model group were given intraperitoneal injection of the same dose of physiological saline;the SPDM group was intervened by SPDM for 20 minutes per time,twice a day,and the same dose of physiological saline was injected into the abdominal cavity;the drug injection group received intraperitoneal injection of OXT at a daily dose of 0.1 mg/kg,and the above interventions were continuous for 14 d.On the 35th day,elevated cross maze and Morris water maze experiments were conducted to assess the rats'anxiety and cognitive abilities;immunofluorescence staining was used to label OXT and c-Fos proteins in the PVN region,as well as OXT and oxytocin receptor(OXTR)in the hippocampus;Western blot was used to check the expression levels of OXTR protein in the hippocampus;ELISA method was used to determine the content of OXT in the hippocampus and hypothalamus of young rats.Results Compared with the blank group,the model group had shorter open arm activity time and fewer open arm entry times(P<0.01);increased escape latency(P<0.05)and decreased distance of the platform's quadrant(P<0.01);reduced positive expressions of OXT neurons and c-Fos in the PVN region,the positive expressions of OXT and OXTR binding in the hippocampus,and the OXTR protein expressions in the hippocampus(P<0.01);and the lower OXT content in the hypothalamus and hippocampus regions(P<0.01).Compared with those of model group,the open arm range of activity increased and the number of open arm entries increased in SPDM group and drug injection group(P<0.05,P<0.01),while the escape latency shortened and the range of activity in the quadrant where the platform was located increased(P<0.05,P<0.01);the positive expressions of OXT neurons and c-Fos in the PVN region,the positive expressions of OXT and OXTR binding in the hippocampus,and the expressions of OXTR in the hippocampus all increased(P<0.01);the OXT content in the hypothalamus and hippocampus increased(P<0.01).Conclusion SPDM can improve cognitive function of ASD model rats,and its mechanism may be related to the activation of OXT neurons in the PVN region,which in turn increases OXT levels and thus strengthens their binding with hippocampal OXTR.