MaFGF对慢性脑缺血再灌注损伤小鼠神经功能保护的机制研究

目的探讨改构型酸性成纤维细胞生长因子(MaFGF)对慢性脑缺血再灌注损伤小鼠神经保护的可能机制。方法将24只雄性C57BL/6J小鼠按随机数字表法分为Sham组、BCAO组和BCAO+MaFGF组,每组各8只。建模完成后,BCAO+MaFGF组鼻内给药MaFGF20μg/(kg.d),其余2组给予相同体积的生理盐水。采用mNSS评估小鼠神经功能损害程度,通过Morris水迷宫试验评估小鼠的学习记忆能力,Nissl染色法观察小鼠海马CA1区神经元细胞的形态结构学改变,Western biot法检测小鼠海马区p-PI3K、p-AKT、GRP170、CHOP、caspase-12蛋白表达水平,免疫荧光染色法观察小鼠海马CA1区神经元p-AKT、GRP170的表达情况。结果与Sham组比较,BCAO组小鼠mNSS评分明显升高(P<0.05),学习记忆能力下降(P<0.05),BCAO组小鼠海马CA1区神经元细胞结构破坏明显,坏死细胞数目明显增多(P<0.05),其海马区CHOP和caspase-12明显升高(P<0.05),而p-PI3K、p-AKT、GRPI70均未见明显改变(P>0.05);与:BCAO组比较,BCAO+MaFGF组小鼠mNSS评分明显降低(P<0.05),学习记忆能力上升(P<0.05),BCAO组小鼠海马CA1区神经元细胞结构较为完整,排列整齐,坏死细胞数目明显减少(P<0.05),其海马区CHOP和caspase-12表达明显降低(P<0.05),而p-PI3K、p-AKT、GRP170表达明显升高(P<0.05)。结论MaFGF能够改善慢性脑缺血再灌注损伤小鼠的神经功能,其可能机制是通过激活PI3K/AKT信号通路,减轻内质网应激,减少细胞凋亡而起神经保护作用。

The protective mechanism of MaFGF on neural function in mice with chronic cerebral ischemia-reperfusion injury

Objective To define the possible mechanism of MaFGF on neuroprotection of cerebral ischemia-reperfusion injury in mice.Methods 24 male C57BL/6J mice(2-3 month)were randomly divided into 3 groups(8 mice in each group):Sham group,BCAO group,BCAO+MaFGF group.The bilateral carotid artery clamping method was used to establish a cerebral ischemia-reperfusion model.After the modeling was completed,the BCAO+MaFGF group was given MaFGF 20μg/(kg·d)intranasally for 28 days,and the other two groups were given the same volume of normal saline.The modified neurological deficit score was used to evaluate the degree of neurological damage in mice;the Morris water maze test was used to evaluate the learning and memory ability of mice;the Nissl staining was used to observe the morphological and structural changes of neurons in the CA1 region of hippocampus.Western blot was used to detect the expression levels of p-PI3K,p-AKT,GRP170,CHOP,and caspase-12 in the hippocampus of mice.Immunofluorescence staining was used to observe the expression of p-AKT and GRP170 in neurons in the CA1 area of the mouse hippocampus.Results Compared with the Sham group,the mNSS score of the mice in the BCAO group was significantly increased(P<0.05),and the learning and memory ability was decreased(P<0.05).The structure of neurons in the CA1 area of the hippocampus of the mice in the BCAO group was significantly damaged,and the number of necrotic cells was increased(P<0.05),and CHOP and caspase-12 in the hippocampus were significantly increased(P<0.05),while p-PI3K,p-AKT,and GRP170 were not changed(P>0.05).Compared with the BCAO group,The mNSS score of the mice in the BCAO+MaFGF group was significandy reduced(P<0.05),and the ability of learning and memory was increased(P<0.05).The structure of the neurons in the CA1 area of the hippocampus in the BCAO group was relatively completed,neady arranged,and the number of necrotic cells was significandy reduced(P<0.05).The expressions of CHOP and caspase-12 in the hippocampus were significandy reduced(P<0.05),while the expression of p-PI3K,p-AKT,and GRP 170 were significantly increased(P<0.05).Conclusion MaFGF improves the neurological function of mice with chronic cerebral ischemia-reperfusion injury.The possible mechanism may be that activating the PI3K/AKT signaling pathway improves endoplasmic reticulum stress and reduced neuronal cell apoptosis,so as to play a neuroprotective effect.