人参皂苷Rc通过调控AMPK通路介导的细胞焦亡减轻小鼠脑缺血再灌注损伤

Ginsenoside Rc attenuates cerebral ischemia-reperfusion injury in mice by regulating AMPK pathway-mediated pyroptosis

目的:探讨人参皂苷Rc对脑缺血再灌注损伤(CIRI)小鼠的保护作用,并从细胞焦亡角度阐释其作用机制。方法:将C57BL/6小鼠随机分为假手术(sham)组、大脑中动脉闭塞/再灌注(MCAO/R)组、人参皂苷Rc+MCAO/R组(Rc组)、AMP活化蛋白激酶(AMPK)激动剂阿卡地新(AICAR)+MCAO/R组(agonist组)和人参皂苷Rc+MCAO/R+AMPK抑制剂Compound C组(Rc+inhibitor组)。对agonist组小鼠给予AICAR(500 mg/kg)腹腔注射,Rc+inhibitor组小鼠给予Compound C(20 mg/kg)腹腔注射;Rc组和Rc+inhibitor组小鼠造模后给予人参皂苷Rc(40 mg/kg)灌胃,每天一次,连续7 d;sham组和MCAO/R组则给予等体积的纯化水。Zea Longa评分观察小鼠神经功能缺损程度,TTC染色观察小鼠脑梗死体积,干湿重法观察小鼠脑水肿程度,HE染色观察小鼠脑组织病理形态的改变,RT-qPCR和Western blot检测小鼠脑组织AMPK、核苷酸结合寡聚化结构域样受体蛋白3(NLRP3)、胱天蛋白酶1(caspase-1)和焦亡效应蛋白消皮素D(GSDMD)的表达,ELISA检测炎症因子白细胞介素1β(IL-1β)和IL-18的含量。结果:Rc组和agonist组小鼠神经功能缺损症状减轻,脑梗死体积减小,脑水肿和神经元病理损伤受到抑制,脑组织pAMPK/AMPK比值和AMPK mRNA表达水平升高,细胞焦亡相关蛋白NLRP3、caspase-1和GSDMD的mRNA和蛋白表达水平降低,炎症因子IL-1β和IL-18表达水平降低。Rc+inhibitor组小鼠脑组织p-AMPK/AMPK比值和AMPK mRNA表达水平较Rc组显著下降(P<0.05),NLRP3、caspase-1和GSDMD的mRNA和蛋白表达水平,以及IL-1β和IL-18表达水平显著升高(P<0.05),小鼠神经功能缺损程度评分升高,脑梗死体积增大,脑水肿和神经元病理损伤显著加重(P<0.05)。结论:人参皂苷Rc可能通过活化AMPK通路抑制NLRP3/caspase-1/GSDMD介导的细胞焦亡,从而减轻小鼠CIRI。

AIM:To comprehend the mechanism by which ginsenoside Rc protects against cerebral ischemia-reperfusion injury(CIRI),with a particular emphasis on pyroptosis.METHODS:The C57BL/6 mice were randomly di-vided into 6 groups:sham group,middle cerebral artery occlusion/reperfusion(MCAO/R)group,ginsenoside Rc+MCAO/R group(Rc group),AMP-activated protein kinase(AMPK)agonist acadesine/5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside(AICAR)+MCAO/R group(agonist group),and ginsenoside Rc+MCAO/R+AMPK inhibitor Compound C group(Rc+inhibitor group).The mice in agonist group were given 500 mg/kg of AICAR intraperitoneally,while those in Rc+inhibitor group were given 20 mg/kg of Compound C intraperitoneally.Ginsenoside Rc was gavaged into the mice in Rc and Rc+inhibitor groups at a dose of 40 mg/kg once per day for 7 d after modeling,while the mice in sham and MCAO/R groups got the same volume of purified water.With the use of the Zea-Longa score,we determined which mice had neu-rological abnormalities.TTC staining was employed for assessing the cerebral infarct amount in mice,and the dry wet weight technique was utilized for determining the degree of cerebral edema.Moreover,HE staining was used to observe pathological alterations in the brain,and Western blot and RT-qPCR were applied for detecting the expression of AMPK,nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3),caspase-1 and gasdermin-D(GSDMD)in the brains of mice.Lastly,ELISA was employed for measuring the levels of inflammatory factors,interleukin-1β(IL-1β)and IL-18.RESULTS:Brain edema,infarct volume and neurological impairments were all diminished in agonist and Rc groups.Additionally,they demonstrated neuronal damage inhibition.The ratio of p-AMPK/AMPK and AMPK mRNA ex-pression in mouse brain tissues was elevated in both Rc and agonist groups.They showed decreased mRNA and protein levels of NLRP3,caspase-1 and GSDMD,as well as the levels of IL-1βand IL-18.Compared with Rc group,there were remarkable decreases in p-AMPK/AMPK ratio and AMPK mRNA expression in the brain tissue of mice in Rc+inhibitor group(P<0.05).The mRNA and protein levels of NLRP3,caspase-1 and GSDMD,and the IL-1βand IL-18 expression levels were significantly increased(P<0.05).Moreover,the neurological deficiency scores and infarct volume were in-creased,and the degrees of cerebral edema and neuronal pathological damage were enhanced(P<0.05).CONCLU-SION:Ginsenoside Rc may inhibit NLRP3/caspase-1/GSDMD-mediated pyroptosis by activating AMPK pathway,thereby reducing CIRI in mice.