经典瞬时受体电位通道蛋白在β淀粉样蛋白诱导的阿尔茨海默病小鼠海马区的表达

摘要

目的：探讨经典瞬时受体电位（TRPC）通道蛋白在阿尔茨海默病（AD）小鼠海马区中的表达情况。方法将36只ICR小鼠随机分为AD组和对照组，每组18只。β淀粉样蛋白（Aβ）1⁃42侧脑室注射制作AD小鼠模型。Morris水迷宫试验测定小鼠学习记忆能力。逆转录聚合酶链反应（RT⁃PCR）检测海马区TRPC1~TRPC7 mRNA的表达。分别采用免疫荧光和Western blotting检测海马区的TRPC4蛋白表达。结果 AD组小鼠水迷宫测试的逃避潜伏期较对照组明显延长（P<0.01），在目标象限停留时间明显缩短（P<0.01），穿越平台次数明显减少（P<0.01）。RT⁃PCR结果显示，在AD组及对照组TRPC1~TRPC7 mRNA均有不同程度的表达，其中AD组TRPC4 mRNA表达较对照组明显增加（P<0.01）。免疫荧光显示TRPC4表达在海马区的神经细胞膜上，且与对照组相比AD组TRPC4表达增加。Western blotting结果显示AD组TRPC4蛋白表达较对照组增加（P<0.05）。结论侧脑室注射Aβ1⁃42寡聚体后，小鼠海马区TRPC4蛋白表达含量增加，提示TRPC4可能参与到钙稳态失调引起的AD的发病机制中。%Objective To investigate the protein expression of the canonical transient receptor potential(TRPC)channel in the hippocampus of amyloidβprotein(Aβ)⁃induced Alzheimer’s disease(AD)mice. Methods A total of 36 ICR mice were randomly divided into AD group and control group,with 18 rats in each group. AD mice models were established by Aβ1⁃42 microinjection into the lateral intracerebroventricular. Learning and memory abilities of the mice were determined using Morris water maze. All TRPC1⁃TRPC7 mRNA levels in the hippocampus of the mice were detected using reverse transcriptase polymerase chain reaction(RT⁃PCR). Hippocampal TRPC4 protein expression was examined using immunofluorescence and Western blotting methods. Results Water maze test results showed that the escape latency of AD group were significant⁃ly longer than that of the control group(P<0.01),and that the target quadrant occupancy of AD group was significantly shortened(P<0.01)and the frequency of platform crossing of AD group was significantly reduced(P<0.01). RT⁃PCR results showed that all TRPC(TRPC1⁃TRPC7) mRNA were expressed in the hippocampal of both AD group and control group. Among these channels ,only TRPC4 mRNA levels of AD group was higher than that of the control group(P<0.01). Immunofluorescence images showed that TRPC4 expressed on the membrane of neurons and the intensities of the immunofluorescence of TRPC4 in AD group were stronger than that of control group. Western blotting results showed that the TRPC4 protein expression of AD group was higher than that of control group(P<0.05). Conclusion The increase of TRPC4 protein expression in the hippocampus of mice after intracerebroventricular injection of Aβ1⁃42 oligomers suggests that TRPC4 may be involved in the pathogenesis of AD induced by calcium homeostasis.