白细胞介素6基因敲除对阿尔茨海默病5×FAD模型小鼠β淀粉样蛋白沉积和认知的影响

目的 探讨白细胞介素6(IL-6)基因敲除对阿尔茨海默病5×FAD转基因小鼠认知及脑组织病理变化的影响。方法 IL-6^+/-小鼠与5×FAD小鼠杂交,构建5×FAD;IL-6^-/-小鼠模型,并选用3、10月龄子代小鼠进行实验。采用行为学实验对小鼠的认知记忆功能进行分析;采用HE染色和β淀粉样蛋白(Aβ)免疫组织化学染色检测小鼠脑组织病理变化。结果 得到5×FAD;IL-6^-/-模型小鼠(3月龄n=20,10月龄n=5)及5×FAD同窝对照小鼠(3月龄n=26,10月龄n=24),子代小鼠数量符合孟德尔定律。新物体识别实验结果显示,与同月龄5×FAD小鼠相比,3月龄5×FAD;IL-6^-/-小鼠的探索指数显著升高,差异有统计学意义(q=3.890,P=0.002)。Morris水迷宫空间探索结果显示,与同月龄5×FAD小鼠相比,3月龄5×FAD;IL-6^-/-小鼠目标象限停留时间及穿台次数增加,差异有统计学意义(q=3.797,P=0.012;q=2.505,P=0.017)。免疫组织化学染色结果显示,IL-6基因敲除显著减少3、10月龄5×FAD小鼠海马(q=13.490,P=0.002;q=45.680,P<0.001)及皮层(q=16.830,P=0.001;q=14.180,P=0.001)的Aβ沉积,差异有统计学意义。结论 IL-6基因敲除可明显改善阿尔茨海默病5×FAD模型小鼠的空间记忆能力,减少小鼠大脑Aβ沉积。

Effects of Interleukin-6 Gene Knockout on β-amyloid Deposition and Cognition in 5×FAD Mouse Model of Alzheimer’s Disease

Objective To explore the effects of interleukin-6 (IL-6) gene knockout on the cognitive function and pathological changes in 5×FAD transgenic mice of Alzheimer’s disease.Methods IL-6^+/- mice were crossed with 5×FAD mice to establish the 5×FAD;IL-6^-/- mouse model,and 3-month-old and 10-month-old mice were selected for experiments.The cognitive function of mice was detected by behavioral tests,and HE staining and β-amyloid (Aβ) immunohistochemical staining were performed to detect the pathological changes of mouse brain tissue.Results The number of 5×FAD;IL-6^-/- model mice (3 months old,n=20;10 months old,n=5) and 5×FAD littermate control (3 months old,n=26;10 months old,n=24) conformed to the Mendel’s law.Compared with that of the 5×FAD mice at the same age,the discrimination ratio of 3-month-old 5×FAD;IL-6^-/- mice increased in the novel object recognition test (q=3.890,P=0.002).Morris water maze test results showed that the 3-month-old 5×FAD;IL-6^-/- mice had longer time spent in target quadrant (q=3.797,P=0.012) and more times of crossing platform (q=2.505,P=0.017) than the 5×FAD mice at the same age.The results of immunohistochemical staining showed that IL-6 knockout reduced the Aβ deposition in the hippocampus (q=13.490,P=0.002;q=45.680,P<0.001) and cortex (q=16.830,P=0.001;q=14.180,P=0.001) of 5×FAD mice.Conclusion IL-6 gene knockout can significantly improve the spatial memory and reduce the Aβ deposition in the brain of 5×FAD mice.