双嘧达莫对阿尔茨海默病大鼠学习记忆的改善作用及机制研究

Improvement Effects and Mechanism of Dipyridamole on Learning and Memory in Rats with Alzheimer's Disease

目的探讨双嘧达莫对阿尔茨海默病(Alzheimer's disease,AD)的防治作用及其作用机制。方法海马注射β-淀粉样蛋白(Aβ25-35)建立大鼠AD模型,选用敞箱试验、Morris水迷宫试验和避暗试验评价双嘧达莫的抗AD疗效;采用酶联免疫吸附法(ELISA)检测海马环磷酸腺苷(cAMP)水平;采用荧光实时定量聚合酶链反应(RT-PCR)、免疫印迹法分别检测大鼠海马脑源性神经营养因子(Brainderived neurotrophic factor,BDNF)、肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)、白细胞介素1β(interleukin-1β,IL-1β)、白细胞介素6(interleukin-6,IL-6)mRNA表达和磷酸化环磷腺苷效应元件结合蛋白(CREB)、核因子(NF)-κB p65蛋白的表达情况。结果双嘧达莫连续给药对大鼠的水平运动得分和垂直运动得分均无明显影响,能显著增加AD大鼠平台象限的游泳时间和平台穿越次数,明显延长AD大鼠进入暗室潜伏期;分子生物学检测结果显示,与假手术组比较,Aβ_(25-35)注射大鼠海马cAMP含量、p-CREB蛋白表达、BDNF mRNA表达显著减少,NF-κB p65蛋白及TNF-α,IL-1β,IL-6的mRNA表达则明显增加,而双嘧达莫均能不同程度逆转Aβ_(25-35)引起的变化。结论双嘧达莫对AD大鼠的学习记忆有显著改善作用,其作用机制可能与激活海马cAMP/CREB/BDNF信号通路和抑制NF-κB介导的炎性反应有关。

Objective To investigate the preventive and therapeutic effects of Dipyridamole in Alzheimer＇s disease（AD） and the mecha- nism of action. Methods The AD model was developed by mircoinjection of Aβ25 -35 into hippocamups of rats. Open field test, Morris water maze test and stepthrough passive avoidance test were used to evaluate the anti- dementia effects of Dipyridamole. The hippocampal cAMP content were detected by using enzyme linked immunosorbent assay（ELISA）. The mRNA expression of BDNF,TNF- α, IL- 1β and IL- 6 in hippocampus were examined by RT- PCR. The protein expression of p- CREB and NF- KB p65 were examined by immunoblotting test（IBT）. Results Dipyridamole continuously treatment didn＇t affect the crossing scores and rearing scores in rats. In the Morris water maze test, it evidently increased the swimming time and crossing times in platform quadrant in AD rats, and it signifi- cantly prolonged latency to the dark compartment in AD rats. The biochemical resutls indicated that compared with the sham group, cAMP contents,p- CREB expression and BDNF mRNA decreased significantly in Aβ25-35 injected rats,while the NF- κB p65 expres- sion,TNF- α mRNA,IL- 1β mRNA and IL-6 mRNA increased significantly. The changes of Aβ25-35 could be reversed at the different levels by Dipyfidamole. Conclusion Dipyridamole can significantly enhance learning and memory function in AD rats, the mechanism may be related to the activation of eAMP/CREB/BDNF signaling pathway and inhibition of NF- κB mediated inflammatory response.