Tao Jinhao, Cui Yuehua, Duan Yu, Zhang Nan, Wang Congmin, Zhang Fayong
Pediatric Emergency and Critical Care Center, Children's Hospital of Fudan University, Shanghai, P.R. China.
Department of Neurosurgery, Huadong Hospital Affiliated to Fudan University, Shanghai, P.R. China.
Oncotarget. 2017 Nov 7;8(63):106283-106295. doi: 10.18632/oncotarget.22290. eCollection 2017 Dec 5.
Ischemic stroke causes irreversible damage to the brain. The hippocampus is a vulnerable region and plays an important role in cognition and locomotor activity. Puerarin is a phytoestrogen that has beneficial effects in treating neurological disorders. How puerarin protects against hippocampal injury and its molecular mechanisms remain to be elucidated. Transient global brain ischemia was induced by 4-vessel occlusion in adult male Sprague-Dawley rats. The rats were pretreated with puerarin alone or together with LY294002 (an PI3K inhibitor) before ischemia/reperfusion (I/R). The open- and closed-field tasks and Morris water maze (MWM) test were used to assess the effects of puerarin on anxiety-like behavioral and cognitive impairment following I/R. Hematoxylin-eosin staining(HE) was used to examine the survival of hippocampal CA1 pyramidal neurons, and immunoblotting was performed to examine the expression of the related proteins. By using the rat model for transient I/R, we demonstrated that puerarin pretreatment significantly increased the travelling distance and number of crossings in the open- and closed-field tests, reduced latency and increased the proportion of distance and time in zone IV in the MWM. The number of live cells in the hippocampus is sharply increased by puerarin pretreatment.We further observed that the levels of phosphorylated Akt1, GSK-3β and MCL-1were elevated and those of cleaved-caspase-3 were reduced in the puerarin-treatment group. Notably, the PI3K inhibitor LY294002 counteracted all of the effects of puerarin. Our findings suggest that puerarin protects the hippocampus from I/R damage by activating the PI3K/Akt1/GSK-3β/MCL-1 signaling pathway.
缺血性中风会对大脑造成不可逆的损伤。海马体是一个易损区域，在认知和运动活动中发挥着重要作用。葛根素是一种植物雌激素，对治疗神经系统疾病具有有益作用。葛根素如何保护海马体免受损伤及其分子机制仍有待阐明。通过四血管闭塞法在成年雄性Sprague-Dawley大鼠中诱导短暂性全脑缺血。在缺血/再灌注（I/R）前，大鼠单独用葛根素或与LY294002（一种PI3K抑制剂）联合预处理。采用旷场和闭场任务以及莫里斯水迷宫（MWM）试验来评估葛根素对I/R后焦虑样行为和认知障碍的影响。苏木精-伊红染色（HE）用于检查海马CA1锥体神经元的存活情况，并进行免疫印迹以检测相关蛋白的表达。通过使用大鼠短暂性I/R模型，我们证明葛根素预处理显著增加了旷场和闭场试验中的行进距离和穿越次数，减少了潜伏期，并增加了MWM中IV区的距离和时间比例。葛根素预处理使海马体中的活细胞数量急剧增加。我们进一步观察到，葛根素治疗组中磷酸化Akt1、GSK-3β和MCL-1的水平升高，而裂解的caspase-3的水平降低。值得注意的是，PI3K抑制剂LY294002抵消了葛根素的所有作用。我们的研究结果表明，葛根素通过激活PI3K/Akt1/GSK-3β/MCL-1信号通路保护海马体免受I/R损伤。
