海马注射β-淀粉样肽对学习记忆和MK2及白细胞介素-6表达的影响

Alteration of learning and memory abilities of the rats and changs of MK2 and IL - 6 expression afterβ- amyloid injection into hippocampus

目的探讨β-淀粉样肽（AB）诱导阿尔茨海默病（AD）大鼠模型中海马丝裂原活化蛋白激酶活化蛋白激酶2（MK2）和白细胞介素-6（IL-6）的表达及其与老年性记忆力减退的关系，研究炎性机制及信号转导在AD中的作用。方法采用立体定向下双侧海马注射Aβ1-42建立AD动物模型，通过Y-迷宫测试、HE染色、免疫组化染色及Westernblot等方法，观测大鼠学习记忆能力、海马组织结构的病理改变及MK2和IL-6的表达情况。结果模型组大鼠Y-迷宫学习记忆能力较对照组明显受损（P〈0．05），HE染色显示，模型组大鼠海马神经元变性、缺失，胶质细胞浸润；免疫组化结果显示模型组大鼠海马CA1区MK2和IL-6免疫阳性细胞表达多见（P〈0．05）；Westemblot显示模型组海马组织MK2条带增宽表达强度高于对照组（P〈0．05），差异有统计学意义。结论MK2信号转导通路在AD的炎症反应机制中可能具有重要的作用。

Objective To study the relationship between the changes in the expression of MK2 and IL- 6 in hippocampus and senile hypomnesia in the rat model of Alzheimer＇ s disease（AD） induced by β -amyloid（Aβ）, and to explore the effects of inflammatory mechanism and cellular signal transduction pathway in AD. Methods The AD models were established by the injection of Aβ1-42 into the bilateral hippocampus of rats. Observed the alteration of learning and memory abilities, histopathological change in hippocampus and the expression of MK2 and IL -6 by means of Y shape maze test, HE, immunohistochemistry and Western blot. Results Y - maze test showed the abilities of learning and memo ry in the model group were apparently decreased,in comparision with the control group （ P 〈 0.05）. By HE staining, hippocampal neuronal loss,denaturation and diffuse glial reaction in CA1 region were observed in the model group. The number of MK2 and IL - 6 imunoreactive neurons within the hippocampal CA1 region in the model group was obviously increased compared with the control group （ P 〈 0.05）. The increasing expression of MK2 and the broadening band of MK2 were demonstrated by Western blot in hippocampus in the model group（ P 〈0.05）. Conclusions We suggest that MK2 signal transduetion pathway may play an important role in neuroinflammatory pathology in AD.