两种孤独症谱系障碍大鼠模型的构建及比较

Establishment and comparison of two different rat models of autism

摘要:

目的：构建并比较丙戊酸钠（valproic acid，VPA）或脂多糖（lipopolysaccharide，LPS）诱导的孤独症大鼠模型，为孤独症研究中动物模型的选择提供科学依据。方法：采用孕中期腹腔注射VPA（G12.5）及LPS（G9.5）的方法分别构建VPA或LPS诱导的子代孤独症大鼠模型（n=28）；监测子代生长发育情况；行为学检测子代大鼠孤独症样行为；ELISA检测LPS模型组子代大鼠血浆炎性细胞因子的表达；Western blot检测VPA模型组子代大鼠前额叶皮质PTEN、p-AKT及p-mTOR蛋白表达水平；高效液相色谱法检测VPA模型组子代大鼠前额叶皮质中5-HT的浓度。结果：2种动物模型均表现出一定程度的发育迟缓，并出现孤独症相关的行为改变。其中，VPA模型组孕鼠生育率有所降低，但无统计学差异（ χ2=3.352，P=0.067），仔鼠死亡率明显升高（χ2=5.561，P=0.018），仔鼠尾部畸形率高达87.8%，明显高于对照组（ χ2=79.109，P=0.000）。LPS处理组子代大鼠血浆白细胞介素（interleukin，IL）-6、IL-1β、干扰素（interferon，IFN）-γ及肿瘤坏死因子（tumour necrosis factor，TNF）-α浓度均明显升高（t=2.108，P=0.049；t=2.312，P=0.033；t=2.809，P=0.016；t=2.110，P=0.049）。VPA处理组子代大鼠前额叶皮质PTEN蛋白表达水平下调（t=13.320，P=0.006），p-AKT、p-mTOR蛋白表达水平增加（t=4.633，P=0.044；t=7.984，P=0.015），5-HT浓度较未处理组明显降低（t=2.145，P=0.049）。结论：2种不同处理大鼠模型均可诱导孤独症样行为，但诱导机制可能存在差异，在科学研究中需要根据研究目的作出适当选择。

Abstract:

Objective：To establish and compare valproic acid（VPA） or lipopolysaccharide（LPS） induced rat model of autism，so as to provide a scientific basis for the selection of animal models in autism research. Methods：Rats were injected intraperitoneally with 500 mg/kg VPA or 100 μg/kg LPS on the gestational day 12.5 or day 9.5 to construct autism model in offspring rat（n=28）. The pup’s physical development was continuously monitored，and social interaction，communication ability，stereotype and repetitive patterns of behaviors were detected in the pups. ELISA kits were used to determine the concentrations of plasma inflammatory cytokines（IL-6，IL-1β，IFN-γ and TNF-α） in the pups with or without LPS treatment. Levels of PTEN，p-Akt and p-mTOR protein expressions in the prefrontal cortex of the pups in the present or absent of VPA treatment were confirmed by Western blot. Concentrations of 5-HT in the prefrontal cortex with or without VPA challenge were detected with high performance liquid chromatography（HPLC）. Results：Both of the two autism models displayed a developmental delay and autism related behavioral abnormality. Levels of IL-6，IL-1β，IFN-γ and TNF-α were increased significantly in the rat offspring following LPS treatment（t=2.108，P=0.049；t=2.312，P=0.033；t=2.809，P=0.016；t=2.110，P=0.049）. The VPA challenge significantly decreased the level of PTEN protein expression（t=13.320，P=0.006），and increased the expression levels of p-AKT and p-mTOR in the pups’ prefrontal cortex after the VPA treatment（t=4.633，P=0.044；t=7.984，P=0.015）. The concentration of 5-HT in the prefrontal cortex was also statistically reduced by VPA treatment（t=2.145，P=0.049）. Conclusion：The both rat models with LPS or VPA treatment lead to autism-like behavors，whereas there are different induce molecular mechanisms. Therefore，we should make reasonable choice on the basis of research objectives in scientific study.