不同干预方式对 ASD 大鼠认知能力的影响及机制探讨

摘要: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。

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

Abstract: Objective Observe the effects of aerobic exercise, enriched environment and their combination oncognitive function and expression of NRXN1, NL3 and Shank3 in hippocampus of rats with ASD, to explore theeffect and possible mechanism of it on correcting autistic abnormal behavior. Method ASD RAT models wereestablished 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 with 10 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 andShank3 protein were detected by western blot the mRNA expression levels of NRXN1, NL3 and Shank3 in rathippocampus were detected by RT-PCR. Result Compared with the control group, ASD model group, aerobicexercise 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 weresignificantly increased ( all P<0. 05) , the escape latency was significantly shortened ( P<0. 05) , the activity timeof the original plateau quadrant was increased ( P<0. 05) , and the mRNA expression of NR3, NRXN1 and Shank3were significantly increased ( P < 0. 05, P < 0. 01) . There was no significant difference between aerobic exercisegroup, enriched environment group and exercise+environment environment group in crossing times, escape latencyand activity time of plateau quadrant and NL3, NRXN1 and Shank3 mRNA expression ( P>0. 05) . ConclusionAerobic 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.