法舒地尔通过抑制脑内小胶质细胞活化并促进其M2极化而改善APP/PS1双转基因小鼠认知功能

Fasudil improves cognition of APP/PS1 transgenic mice via inhibiting the activation of microglia and shifting microglia phenotypes from M1 to M2

目的观察Rho激酶抑制剂法舒地尔(fasudil)在治疗阿尔茨海默病(AD)模型淀粉样前体蛋白/早老素1双转基因(APP/PS1 Tg)小鼠中对认知功能及小胶质细胞极化的调控作用。方法采用8月龄雄性APP/PS1 Tg小鼠作为AD模型,随机分为法舒地尔治疗组[腹腔注射法舒地尔,25 mg/(kg·d)]、生理盐水组(腹腔注射),持续治疗2个月;同龄同性别野生型为对照组。应用Morris水迷宫(MWM)检测各组小鼠空间认知功能,Western blot法检测小鼠脑组织β淀粉样蛋白(Aβ)、小胶质细胞表面标志CD11b的水平,免疫荧光组织化学染色法检测小鼠脑组织Aβ_(1-42)、CD11b的表达和分布。Western blot法和免疫荧光组织化学染色法检测M1型小胶质细胞[标志物诱导型一氧化氮合酶(iNOS)]和M2型小胶质细胞[标志物精氨酸酶1(ARG1)、CD206]在海马和大脑皮层的表达水平和分布。结果与野生型小鼠相比,10月龄APP/PS1 Tg小鼠生理盐水组的MWM指标[到达平台时间、到达平台的平均距离、第一次进入西南(SW)象限的时间]明显增加,认知功能下降,这些行为变化可被法舒地尔所拮抗。此外,法舒地尔降低APP/PS1 Tg小鼠的海马DG区和CA3区、皮层区的Aβ_(1-42)表达,减少小胶质细胞数量,抑制小胶质细胞iNOS表达,促进ARG1、CD206表达,促进激活的小胶质细胞由M1型向M2型转化。结论法舒地尔通过抑制脑内小胶质细胞活化并促进其M2型极化,改善APP/PS1双转基因小鼠空间认知功能障碍。

Objective To examine the regulatory effects of Rho kinase inhibitor fasudil on cognition and microglia polarization in APP/PS1 transgenic（ APP/PS1 Tg） mice,a widely used model of Alzheimer＇s disease（ AD）. Methods Male APP/PS1 Tg mice at 8 months of age were randomly divided into two groups： Fasudil（ 25 mg/kg） and saline,i. p.,once daily for 2 months; age-and gender-matched wild type（ WT） mice without treatment were used as the controls. The Morris water maze（ MWM） test was applied to examine spatial cognition of mice. Aβ_（1-42） deposition,the microglia surface marker CD11 b,and the M1 and M2 microglia surface markers [iNOS,arginase 1（ ARG1） and CD206] in the hippocampus and cerebral cortex were analyzed by immunohistochemistry and Western blotting. Results Compared with WT controls,APP/PS1 Tg mice（ 10 months old at the time of testing） treated with saline displayed increases in the latency to target,mean distance to target,latency 1 st entrance to SW quadrant during the MWM test; they also showed increased latency and mean distance entering to the target in the MWM test,indicating their impaired cognition,which was reversed by fasudil. In addition,fasudil decreased the expressions of Aβ_（1-42） and iNOS and increased ARG1/CD206 in the hippocampus and cerebral cortex.Further,the microglia marker CD11 b had an overlap with the M1 marker iNOS or the M2 markers ARG1/CD206 in the cerebral cortex of the AD mice following fasudil treatment. Conclusion Fasudil reverses spatial cognitive dysfunction in APP/PS1 Tg mice via facilitating the transformation of Aβ_（1-42）-activated microglia from the M1 to M2 phenotype.