冬凌草甲素对大鼠糖尿病心肌缺血再灌注损伤的保护作用及其机制

Protective effects and mechanism of oridonin against diabetic myocardial ischemia-reperfusion injury in rats

目的以糖尿病诱导大鼠心肌缺血再灌注(ischemia reperfusion,I/R)损伤模型为研究对象,探讨冬凌草甲素(oridonin,Ori)对心肌I/R模型大鼠心肌病理损伤、抗炎等方面的治疗作用及其可能机制。方法将大鼠随机分为Ctrl组、I/R组(模型组)、I/R+Ori(5 mg)组、I/R+Ori(10 mg)组和I/R+Ori (20 mg)组,前2组灌胃给予生理盐水,后3组灌胃给予冬凌草甲素溶液;检测大鼠平均动脉压(mean ventricular systolic pressure,MAP)、左室收缩压(left ventricular systolic pressure,LVSP)、心率(heart rate,HR);HE染色和TUNEL染色检测心肌损伤和细胞凋亡情况;ELISA检测大鼠血清中心损标记物肌红蛋白(myoglobin,Mb)、肌钙蛋白-Ⅰ(troponin-Ⅰ,cTnⅠ)和肌酸激酶同工酶(creatine kinase-MB,CK-MB)表达水平,氧化应激因子谷胱甘肽(glutathione,GSH)、超氧化物歧化酶(superoxide dismutase,SOD)、丙二醛(MDA)的含量,以及心肌炎标记分子白介素-1β(inerleukin-1β,IL-1β)和肿瘤坏死因子-α(tumor necrosis factor alpha,TNF-α)的含量;免疫组织化学检测心肌组织中白介素-6(inerleukin-6,IL-6)的表达水平;蛋白印迹检测心肌组织中转化生长因子β1(TGF-β1)、磷酸化核转录因子p65(p-NF-κB p65)、肿瘤坏死因子(tumor necrosis factor alpha,TNF-α)蛋白表达情况。结果冬凌草甲素能上调模型大鼠MAP、HR和LVSP(P<0.01);减少心肌组织病理损伤(P<0.01);抑制CK-MB、cTnⅠ和Mb表达(P<0.01);上调SOD、GSH活性,下调MDA含量(P<0.01);减少IL-6、TNF-α和IL-1β表达水平(P<0.01);且抑制TGF-β1、P-NF-κB和TNF-α蛋白表达(P<0.01)。结论冬凌草甲素能改善糖尿病心肌缺血再灌注损伤模型大鼠的心脏功能、减少心肌损伤和细胞凋亡、降低氧化应激和炎症分子表达,其机制可能与抑制NF-κB信号通路活化有关。

This study was performed to investigate the therapeutic effects of oridonin on myocardial pathological damage and anti-inflammation in diabetic rats induced by myocardial ischemia reperfusion(I/R)and its possible mechanism.Rats were randomly divided into control group,I/R group(model group),I/R+Ori group(5 mg),I/R+Ori group(10 mg)and I/R+Ori group(20 mg),while the first two groups were given normal saline by gavage administration,and the latter three groups were given oridonin by gavage administration.The mean ventricular systolic pressure(MAP),left ventricular systolic pressure(LVSP)and heart rate(HR)were measured;while the myocardial injury and apoptosis were respectively detected by HE staining and TUNEL staining.Cardiac injury markers(Mb,cTnI and CK-MB),oxidative stress factors(GSH,SOD and MDA)and myocarditis marker molecule(IL-1βand TNF-α)were detected by ELISA;the expression of IL-6 in myocardium was detected by immunohistochemical;the protein expression of TGF-β1,p-NF-κB p65 and TNF-αin myocardium were detected by Western blotting.Data showed that oridonin could up-regulate the levels of MAP,HR and LVSP in diabetic rats with ischemia-reperfusion injury(P<0.01),reduce the injury of myocardial tissue(P<0.01),inhibit the expression of CK-MB,cTn I and Mb(P<0.01),upregulate the activity of SOD and GSH,down-regulate MDA level(P<0.01),reduce the expression levels of IL-6,TNF-αand IL-1β(P<0.01),as well as inhibit the expression of TGF-β,p-NF-κB and TNF-α(P<0.01).In conclusion,Oridonin can improve cardiac function,reduce myocardial injury,cell apoptosis,oxidative stress and the expression of inflammatory molecules in diabetic rats with myocardial ischemia-reperfusion injury.And the mechanism may relate to the inhibition of NF-κB signaling pathway activation.