山楂叶总黄酮对心肌缺血再灌注大鼠心肌病变及Akt/Nrf2通路的影响

Effect of hawthorn leaves flavonoids on cardiomyopathy and Akt/Nrf2 pathway in myocardial ischemia-reperfusion rats

目的探讨山楂叶总黄酮(HLF)对心肌缺血再灌注大鼠心肌组织病理学改变的影响及其机制。方法采用随机数表法将192只健康雄性大鼠分为假手术组、模型组、HLF(25、50、100 mg/kg)组和维拉帕米(Ver)1 mg/kg组,各32只;除假手术组外,其他组均通过夹闭左冠状动脉前降支30 min复制心肌缺血再灌注大鼠模型,各组均于造模前10 min腹腔注射给药(假手术组和模型组予0.9%氯化钠溶液)。再灌注2 h后,硝基蓝四氮唑(NBT)染色法检测心肌梗死体积;苏木精-尹红(HE)染色法观察心肌组织病理学改变并行损伤评分,透射电子显微镜观察心肌细胞超微结构;硫代巴比妥酸法检测心肌丙二醛(MDA)含量,黄嘌呤氧化法、钼酸铵法检测超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活力,酶联免疫吸附(ELISA)法检测肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)含量;免疫蛋白印迹(Western blot)法检测蛋白激酶B(Akt)、磷酸化Akt(p-Akt)、核因子E_(2)相关因子2(Nrf2)、核因子-κB(NF-κB)蛋白表达。结果与模型组比较,HLF 50、100 mg/kg组和Ver 1 mg/kg组心肌梗死体积降低,心肌组织病理学改变明显改善、损伤评分降低,胞膜、胞核、线粒体等细胞器超微结构病变明显改善,MDA含量降低且SOD、CAT活力升高,TNF-α、IL-1β、IL-6含量降低,p-Akt、Nrf2蛋白表达上调且NF-κB表达下调(P<0.05或P<0.01)。与Ver 1 mg/kg组比较,HLF 100 mg/kg组心肌梗死体积降低,损伤评分降低,心肌细胞超微结构病变明显改善,MDA含量降低且SOD活力升高,TNF-α、IL-6含量降低,p-Akt、Nrf2表达上调且NF-κB表达下调(P<0.05或P<0.01)。结论HLF对心肌缺血再灌注大鼠心肌病理学改变和细胞超微结构病变具有保护作用,其机制可能与激活Akt/Nrf2通路,抑制氧化应激和炎症反应有关。

Objective To study the effect of hawthorn leaves flavonoids(HLF)on the myocardial histopathological changes in rats with myocardial ischemia-reperfusion and its mechanism.Methods According to the random number table method,the 192 experimental rats were divided into a sham operation group,a model group,three HLF groups(respectively at the dose of 25,50,100 mg/kg)and a verapamil group(Ver group)(1 mg/kg),with 32 rats in each group.Except the sham operation group,a myocardial ischemia-reperfusion rat model was prepared by clamping the anterior descending branch of the left coronary artery for 30 minutes,while the rats in every group were given drugs by intraperitoneal injection(the rats in the sham operation group and model group were given 0.9%sodium chloride solution)10 minutes before modeling.The volume of myocardial infarction was detected by nitro blue tetrazolium(NBT)staining two hours after reperfusion.The histopathological changes of myocardium were observed by hematoxylin-Yin Hong(HE)staining,its injury score was calculated and the myocardial cell ultrastructure was observed by transmission electron microscope.The malondialdehyde(MDA)content was detected by the thiobarbituric acid method,and the superoxide dismutase(SOD)and catalase(CAT)activities were detected by the xanthine oxidation method and ammonium molybdate method respectively.The contents of tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β)and interleukin-6(IL-6)were determined by enzyme-linked immunosorbent assay(ELISA).The expression of protein kinase B(Akt),phosphorylated Akt(p-Akt),nuclear factor E_(2) related factor 2(Nrf2),nuclear factor-κB(NF-κB)were determined by Western blot.Results Compared with the model group,in the HLF groups(50,100 mg/kg)and the Ver group,the myocardial infarction volume was decreased,the myocardial histopathological changes were significantly improved,the injury score was decreased,the ultrastructural lesions of organelles such as cell membrane,nucleus and mitochondria were significantly improved,the content of MDA was decreased,the activities of SOD and CAT were increased,the contents of TNF-α,IL-1βand IL-6 were decreased,the protein expressions of p-Akt and Nrf2 were up-regulated while the expression of NF-κB was down-regulated(P<0.05 or P<0.01).Compared with the Ver group,in the HLF 100 mg/kg group,the myocardial infarction volume was decreased,the injury score was decreased,the myocardial cell ultrastructure lesions were signi?cantly improved,the MDA content was decreased and the SOD activity was increased,the contents of TNF-αand IL-6 were decreased,the expressions of p-Akt and Nrf2 were up-regulated while the NF-κB expression was down-regulated(P<0.05 or P<0.01).Conclusion HLF has a protective effect on myocardial pathological changes and cellular ultrastructural lesions in myocardial ischemia-reperfusion rats,and its mechanism may be related to activating the Akt/Nrf2 pathway and inhibiting the oxidative stress and inflammatory response.