颅内注射淀粉样β蛋白片段1-42和thiorphan对恒河猴脑内淀粉样β蛋白表达的影响

Effect of intracranial co-infusion of amyloid beta-protein fragment 1-42 and thiorphan on amyloid beta-protein expression in brain of Macaca mulatta

目的探讨颅内注射淀粉样β蛋白片段1-42(Aβ1-42)和thiorphan对恒河猴脑内Aβ表达的影响。方法将恒河猴随机分为模型组(n=3)和正常对照组(n=1),模型组开颅后于大脑皮质和基底神经节先注射thiorphan以消耗已存在的脑啡肽酶,然后缓慢注射纤丝状Aβ1-42,再植入含有thiorphan的微渗透泵到基底神经节,持续28d;正常对照组仅注射生理盐水。至50d时处死恒河猴,开颅取大脑,免疫组织化学法观察海马、基底神经节和大脑皮质等部位Aβ1-42的表达。结果正常对照组恒河猴海马、基底神经节和大脑皮质Aβ1-42免疫反应阳性,30个高倍视野(×400)的积分吸光度(IA)分别为0.22±0.06,0.20±0.04和0.19±0.07。模型组3只恒河猴海马、基底神经节和大脑皮质Aβ1-42免疫反应均明显增强,海马IA分别为0.57±0.05,0.60±0.05和0.61±0.05;基底神经节IA分别为0.62±0.06,0.63±0.05和0.65±0.05;大脑皮质IA分别为0.67±0.06,0.68±0.05和0.65±0.07。结论颅内联合注射Aβ1-42和thiorphan可增加脑内Aβ1-42的表达。

OBJECTIVE To observe the change of amyloid beta-protein (Aβ) expression in the Macaca mulatta brain after intracranial co-infusion of Aβ fragment 1-42 (Aβ1-42) and thiorphan. METHODS Four M.mulatta were randomly divided into model group (n=3) and control group (n=1). In model group they had their skulls drilled and infused with thiorphan to the cerebral cortex and basal ganglia to consume the existing neprilysin and then infused with the fibrilla Aβ1-42. For prolonged administration of inhibitor to basal ganglia, a miniosmotic pump was implanted in the M. mulatta brain and kept working for 28 d. The one in control group was injected with saline. By 50 d all the M. mulatta were sacrificed. The expression of Aβ1-42 in hippocampus, basal ganglia and cerebral cortex was observed with immunohistochemical staining. RESULTS The integrated Absorbance (IA) of Aβ1-42 immunostaining in 30 high power fields (×400) of hippocampus, basal ganglia and cerebral cortex of control group was 0.22±0.06,0.20±0.04 and 0.19±0.07, respectively. The Aβ1-42 expressions in hippocampus, basal ganglia and cerebral cortex of 3 M. mulatta in model group were all elevated. The IA of Aβ1-42 immunostaining in hippocampus of each M. mulatta was 0.57±0.05,0.60±0.05 and 0.61±0.05, respectively. In basal ganglia, the IA was 0.62±0.06,0.63±0.05 and 0.65±0.05, respectively. In cerebral cortex, the IA was 0.67±0.06,0.68±0.05 and 0.65±0.07, respectively. CONCLUSION Intracranial co-infusion of Aβ1-42 and thiorphan in the M. mulatta brain causes the increase of Aβ1-42 expression in brain.