齐墩果酸通过抑制JAK2/STAT3信号通路减轻大鼠脑缺血再灌注损伤

Oleanic acid alleviates cerebral ischemia-reperfusion injury in rats by inhibiting the JAK2/STAT3 signaling pathway

目的探讨齐墩果酸(oleanic acid,OA)在脑缺血再灌注(ischemia reperfusion,I/R)大鼠中的保护作用及JAK2/STAT3信号通路的作用。方法72只成年雄性SD大鼠,随机分为假手术组、模型组(I/R)、OA组(I/R+OA)和抑制剂组(I/R+OA+FLLL32)。采用线栓法构建左侧大脑中动脉I/R模型,模型制作后分别通过腹腔注射和侧脑室注射给予OA和JAK2/STAT3抑制剂FLLL32,共7 d。通过行为学评价神经功能缺损,2,3,5-三苯基氯化四氮唑染色检测梗死体积,蛋白质印迹分析缺血脑组织Bcl-2、Bax、JAK2、STAT3、p-JAK2、p-STAT3表达,免疫荧光染色检测缺血脑区胱天蛋白酶-3阳性细胞百分比。结果与假手术组比较,模型组出现明显神经功能缺损和脑梗死灶,Bax和胱天蛋白酶-3表达以及JAK2和STAT3蛋白磷酸化水平均显著上调,而Bcl-2显著下调。与模型组比较,OA组和抑制剂组神经功能损伤显著减轻,梗死体积显著缩小,Bax表达、JAK2和STAT3蛋白磷酸化水平以及胱天蛋白酶-3阳性细胞百分比均显著降低,而Bcl-2表达显著上调。结论OA可能通过抑制JAK2/STAT3信号通路的激活减少神经细胞凋亡,进而减轻I/R损伤。

Objective To investigate the protective effects of oleanic acid(OA)on cerebral ischemia-reperfusion(I/R)injury in rats and the role of JAK2/STAT3 signaling pathway.Methods Seventy-two adult male SD rats were randomly divided into sham-operation group,model group(I/R),OA group(I/R+OA),and inhibitor group(I/R+OA+FLLL32).The left middle cerebral artery I/R model was constructed by the thread occlusion method.After modeling,OA and JAK2/STAT3 inhibitor FLLL32 were administered via intraperitoneal injection and lateral ventricular injection,respectively,for a total of 7 days.Neurological deficits were evaluated by behavioral methods,infarct volume was detected by 2,3,5-triphenyltetrazolium chloride staining,the expressions of Bcl-2,Bax,JAK2,STAT3,p-JAK2 and p-STAT3 in ischemic brain tissue were analyzed by Western blotting,and the percentage of caspase-3 positive cells in ischemic brain area was detected by immunofluorescence staining.Results Compared with sham-operation group,the model group showed significant neurological deficits and cerebral infarction lesions.The expressions of Bax and caspase-3,as well as the phosphorylation levels of JAK2 and STAT3 proteins,were significantly decreased,while the expression of Bcl-2 was significantly up-regulated.Compared with model group,neurological deficits and infarct volume were significantly reduced in OA and inhibitor groups,the expression of Bax,the phosphorylation levels of JAK2 and STAT3,and the percentage of caspase-3 positive cell were significantly decreased,while the expression of Bcl-2 was significantly up-regulated.Conclusion OA may reduce neuronal apoptosis by inhibiting the activation of the JAK2/STAT3 signaling pathway,and then alleviate I/R injury.