探讨海马内注射淀粉样蛋白前体蛋白(APP)抗体诱导细胞表面APP的铰链是否影响大鼠的水迷宫行为学以及是否诱导神经元的退行性改变,并进一步探讨其可能的机制.成年雄性SD大鼠海马内分别注射生理盐水、对照IgG和APP抗体.水迷宫行为学检测测试动物的学习和记忆能力.Cresyl Violet(CV)和Fluoro-Jade B染色观察神经元的退行性变.免疫组织化学方法检测MAP-2和磷酸化paxillin及磷酸化tau蛋白在海马的异常表达和分布.海马内注射APP抗体可延长动物的寻台潜伏期,减少大鼠在平台所在象限的探索时间和穿梭次数.CV和Fluoro Jade—B染色结果显示,海马注射APP抗体可导致海马锥体细胞的死亡和退变.同时伴MAP2免疫染色的减少和磷酸化paxillin及磷酸化tau的免疫染色的增加.上述结果表明,海马内注射APP抗体可诱导学习和记忆功能障碍及神经元的退行性改变,其机制可能与MAP-2和磷酸化paxillin及磷酸化tau的异常表达分布有关.
In order to evaluate whether APP-Ab injection to hippocampus influence Morris water maze behavior and neuronal degeneration and to further investigate the potential mechanisms, rats were anaesthetized and fixed on a stereotaxic instrument and bilateral injection 1 μl of anti-APP antibody (10 g/L) was made using microsyringe. Meanwhile, NS or IgG-intrahippocampal-injected (1μl; 10 g/L) rats served as vehicle controls. Antibodies were injected into the hippocampus (AP: -3.0; L and R: 2.0; V: 3.5 mm). The Morris water maze test was performed to test animals' learning and memory ability. After APP-Ab injection, cresyl violet and Fluoro-Jade B staining were used to investigate neuronal degeneration. Immunohistochemistry staining was used to detect MAP-2 and phosphorylated paxillin and tau distribution at hippocampus. APP-Ab injection to hippocampus could prolong the escape latency to find hidden platform and decreased the exploratory time and crossing numbers in the training quadrant. APP-Ab injection was also shown to cause neuronal cell death and degeneration by cresyl violet (CV) staining and Fluoro Jade-B (FJB) staining. Moreover, decreased MAP2 immunoreactivity, increased phosphorylated paxillin and phosphorylated tan immunostaining were observed in the pyramidal cells. It can be concluded that intrahippocampus injection of APP-Ab could induce cognitive deficits and neurodegenerative changes. APP-Ab injection also affected the distribution of MAP2, paxillin and tau protein.