不同干预方式对ASD大鼠认知能力的影响及机制探讨

Effects of Different Interventions on Cognitive Ability in ASD Rats and Possible Mechanisms

目的观察有氧运动、丰富环境及二者结合对孤独症谱系障碍(ASD)大鼠认知功能和海马组织中ASD易感基因NRXN1、NL3和Shank3表达的影响,探讨其纠正自闭症异常行为的效果及其可能机制。方法采用向Wistar孕鼠腹腔注射丙戊酸钠建立ASD大鼠模型,选取40只成功建模的子代大鼠随机分为有氧运动组、丰富环境组、有氧+环境组以及ASD模型组,每组10只;在常规饲养的母鼠所产子代中随机挑选10只作为空白对照组。有氧运动组大鼠接受持续8周、6次/周、每次在同一时间段、持续90 min的游泳运动干预;丰富环境组大鼠饲养于内有各种玩具、可供大鼠嬉戏玩耍的丰富环境饲养笼;运动+环境组接受运动干预,同时在丰富环境中饲养;ASD模型组和空白对照组不予干预。干预后,采用旷场实验和Morris水迷宫实验观察其行为学表现与改变;采用Western blot检测大鼠海马组织中NRXN1、NL3和Shank3蛋白表达情况;采用RT-PCR检测大鼠海马组织中NRXN1、NL3和Shank3的mRNA表达水平。结果与空白组比较,ASD模型组、有氧运动组、丰富环境组及有氧+环境组的穿格次数少(P<0.05)、逃避潜伏期长(P<0.05)、原平台象限活动时间缩短(P<0.05),NL3、NRXN1和Shank3蛋白的mRNA表达均明显降低(P<0.05);与ASD模型组比较,有氧运动组、丰富环境组及有氧+环境组的穿格次数明显增加(P<0.05)、逃避潜伏期明显缩短(P<0.05)、原平台象限活动时间延长(P<0.05),大鼠海马组织中NL3、NRXN1、Shank3蛋白的mRNA表达均明显升高(P<0.05,有氧+环境组P<0.01);有氧运动组、丰富环境组及有氧+环境组相互比较,其穿格次数、逃避潜伏期、原平台象限活动时间与NL3、NRXN1和Shank3蛋白的mRNA表达均无显著性差异(P>0.05)。结论有氧运动、丰富环境及二者结合均可提高丙戊酸钠诱导的ASD模型大鼠的认知能力,一定程度纠正其异常行为,有氧运动结合丰富环境的干预效果优于单纯的有氧运动、单纯的有氧运动优于单纯的丰富环境。其作用机制可能与NRXN-NLGN-SHANK通路有关。

Objective Observe the effects of aerobic exercise,enriched environment and their combination on cognitive function and expression of NRXN1,NL3 and Shank3 in hippocampus of rats with ASD,to explore the effect and possible mechanism of it on correcting autistic abnormal behavior.Method ASD RAT models were established by intraperitoneal injection of VPA into pregnant Wistar rats.Forty offspring rats were randomly divided into aerobic exercise group,enriched environment group,exercise+environment group and ASD model group with10 rats in each group.A total of 10 rats were randomly selected as the control group.The Rats in the aerobic exercise group received swimming exercise intervention lasting 8 weeks,6 times per week,each time in the same time period,lasting 90 minutes,and the rats in the enriched environment group were kept in an enriched environment cage with various toys for playing.The exercise+environment group received exercise intervention and was raised in enriched environment,while the ASD model group and the control group did not.The behavioral changes were observed by open field test and Morris water maze test,and the expressions of NRXN1,NL3 and Shank3 protein were detected by western blot the mRNA expression levels of NRXN1,NL3 and Shank3 in rat hippocampus were detected by RT-PCR.Result Compared with the control group,ASD model group,aerobic exercise group,enriched environment group and aerobic+enriched environment group had fewer perforation times(P<0.05),longer escape latency(P<0.05),shorter activity time of the original platform quadrant(P<0.05),lower mRNA expression of NRXN1 and Shank3(P<0.05).Compared with the ASD model group,the crossing times of aerobic exercise group,enriched environment group and exercise+environment environment group were significantly increased(all P<0.05),the escape latency was significantly shortened(P<0.05),the activity time of the original plateau quadrant was increased(P<0.05),and the mRNA expression of NR3,NRXN1 and Shank3 were significantly increased(P<0.05,P<0.01).There was no significant difference between aerobic exercise group,enriched environment group and exercise+environment environment group in crossing times,escape latency and activity time of plateau quadrant and NL3,NRXN1 and Shank3 mRNA expression(P>0.05).Conclusion Aerobic exercise,enriched environment and the combination of both can improve the cognitive ability and correct abnormal behavior of ASD rats induced by VPA,the intervention effect of aerobic exercise combined with rich environment is better than pure aerobic exercise and pure aerobic exercise than pure rich environment.Its mechanism of action may be related to the NRXN-NLGN-SHANK pathway.