孕早期Poly-IC暴露致Sprague-Dawley大鼠孤独症谱系障碍模型的建立及神经病理学变化

摘要

目的 建立暴露于Poly-IC环境下的孤独症谱系障碍模型,分析模型发育、行为及神经病理学变化,明确Sprague-Dawley(SD)大鼠是否适用于孤独症谱系障碍的研究.方法 选择孕12 d SD大鼠10只,采用随机数字表法分组,实验组腹腔注射Poly-IC(5 mg/kg),对照组腹腔注射9g/L盐水(等容积),每组5只.记录各组子代大鼠体质量、睁眼时间、游泳表现,并行水迷宫、社会交流能力等神经行为学检测,评价实验鼠的发育情况及是否存在孤独症样行为;间接免疫荧光双标染色观察子代大鼠海马病理改变.结果 与对照组相比,各测量点实验组子代大鼠体质量较轻,睁眼时间延迟,游泳得分偏低,差异均有统计学意义(均P＜0.05).社会交流能力测试中“接近-逃避”分数偏低,Morris水迷宫实验中到达平台潜伏期明显延长,正确穿越平台次数明显减少,差异均有统计学意义(均P ＜0.05).病理结果显示:实验组子代大鼠海马CA1区盐皮质激素受体(MR)光密度值(0.061 3 ±0.028 8)和糖皮质激素受体(GR)光密度值(0.041 9±0.0403)均较对照组(MR:0.081 3 ±0.053 9;GR:0.061 2 ±0.043 6)减低,差异均有统计学意义(t=10.319、10.241,均P＜0.05);实验组MR/GR比值(同一视野相同面积下MR和GR光密度值的比值)与对照组差异无统计学意义(P＞0.05).结论 孕早期Poly-IC暴露可致SD大鼠子代运动发育滞后,社会交流能力受损,记忆学习能力减退,出现孤独症样症状,与海马细胞表面MR、GR表达异常有关,因此,SD大鼠孕早期Poly-IC暴露可用于孤独症谱系障碍模型的建立,为孤独症谱系障碍的研究提供平台.%Objective Through modelling autism spectrum disorder(ASD) in condition of Poly-IC,to analyze the development,nervous pathological changes and behavior of rats in experiments,and to define whether the Sprague-Dawley(SD) rats are suitable for the study of ASD.Methods Ten SD rats were randomly divided in 2 groups with 5 rats in each group.The experimental group rats were injected intraperitoneally with 5 mg/kg Poly-IC at gestational day 12,while the rats in control group were injected intraperitoneally with 9 g/L normal saline at the gestational day 12.The body weight,eye-opening time,swimming performance,and conduct parallel water maze test,social communication ability test of each offspring were recorded,and the developmental state of rats and the existence of autism-like social behavior were evaluated.The alterations in hippocampus morphology of offspring rats were indirectly observed with immunofluorescence double standard dyeing.Results Compared with the control group,the weights of the experimental rats were lighter,opening-eye time was delayed,swimming score was lower,in each measurement point.The differences above all were significant(all P ＜0.05).The "near-escape" scores of experiment rats in social communication ability test were lower than those of rats in control group.The rats in the experimental group needed more time to get the Morris water maze platform,and the times of rightly run through the Morris water maze decreased significantly,and the differences were significant (all P ＜ 0.05).Pathological results revealed that the mineralocorticoid receptor (MR) average optical density value (0.061 3 ± 0.028 8) and the glucocorticoid receptor (GR) mean optical density value (0.041 9 ± 0.040 3) in hippocampal CA1 area of experiment rats were lower than those of the control group (MR:0.081 3 ±0.053 9;GR:0.061 2 ±0.043 6) (t =10.319,10.241;all P ＜0.05).There was no significant difference between MR/GR ratio(the ratio of MR and GR optical density value in the same vision area) in experimental group and in the control group.Conclusions The Poly-IC during early pregnancy can cause lag behind in motor development,harm the social communication ability,lose memory ability to learn,and develop ASD symptoms of SD rat,and these symptoms may be associated with abnormal expression of MR and GR on the hippo-camp cells surface.AS a consequence,early pregnant SD rats exposed to Poly-IC can be used for the establishment of the model of ASD which can provide a platform for the research of ASD.