cGAMP通过激活PI3K-AKT通路减轻小鼠脑缺血恢复期的损伤

cGAMP reduces neuronal damage in the mouse cerebral ischemic recovery phase by activating the PI3K-AKT pathway

目的 研究cGAMP对小鼠脑缺血恢复期的影响及初步作用机制。方法 采用线栓法制备小鼠大脑中动脉闭塞(MCAO)模型,通过行为学评分和组织病理染色观察cGAMP 对MCAO小鼠恢复期的影响。激光散斑仪器观察cGAMP对MCAO小鼠恢复期的脑血流量的影响,使用苏木精-伊红染色(HE)和尼氏染色(NISSL)观察cGAMP对MCAO小鼠大脑皮层神经元的影响,使用实时荧光定量聚合酶链反应(PCR)检测小鼠大脑皮层中肿瘤坏死因子α(TNF-α)和精氨酸酶1(Arg-1)的表达,使用蛋白免疫印迹法(Western blot)检测小鼠大脑皮层中PI3K、p-PI3K、AKT、p-AKT的表达。结果 行为学观察结果显示,与模型组相比,缺血期的MCAO小鼠经 cGAMP 处理后,行为学评分降低,在提尾测试、平衡木试验和前肢抓地力牵引测试中,其运动功能均显著恢复。HE、NISSL染色中,cGAMP可减轻脑缺血恢复期小鼠神经元损伤。PCR结果表明cGAMP处理可以降低脑缺血恢复期小鼠脑组织TNF-α的表达,升高Arg-1的表达。在Western blot结果中,cGAMP处理能够显著促进PI3K、AKT的磷酸化(P<0.05)。结论 cGAMP 能明显改善脑缺血恢复期小鼠运动功能,可能是通过激活PI3K-AKT通路减轻小鼠脑缺血恢复期的神经元损伤发挥治疗作用。

Objective To determine the effect of cGAMP on the cerebral ischemia recovery phase in mice and its preliminary mechanism.Methods The middle cerebral artery occlusion(MCAO)model was established in mice with the suture method.The effect of cGAMP on the cerebral ischemia recovery phase of MCAO mice was evaluated with behavioral scoring and histopathological staining.Laser speckle instrument was used to observe the effect of cGAMP on the cerebral blood flow in MCAO model during the ischemic phase.The effect of cGAMP on the cortical neurons in MCAO mice was observed with hematoxylin-eosin(HE)and NISSL staining.The expressions of tumor necrosis factorα(TNF-α)and arginase-1(Arg-1)in the cerebral cortex of mice were detected with real-time fluorescent quantitative polymerase chain reaction(PCR),and the expressions of PI3K,p-PI3K,AKT,and p-AKT were detected with Western blot.Results Behavioral observations showed that as compared with the model group,cGAMP-treated MCAO mice during the ischemic phase displayed reduced behavioral scores and significant recovery in elevated body swing test,balance beam test,and forelimb grip traction test,indicating improved motor function.HE and NISSL staining showed that cGAMP alleviated neuronal damage in mice during the cerebral ischemia recovery phase.PCR demonstrated that cGAMP treatment reduced the expression of TNF-αin the brain tissue of mice during the cerebral ischemia recovery phase while increased the expression of Arg-1.Western blot showed that cGAMP treatment greatly promoted the phosphorylation of PI3K and AKT(P<0.05).Conclusion cGAMP significantly improves the motor function in mice during the cerebral ischemia recovery phase,and its therapeutic effect may be attributed to the activation of the PI3K-AKT pathway to alleviate neuronal damage during the cerebral ischemia recovery phase.