电针对内毒素血症小鼠肠损伤时线粒体融合和分裂的影响及HO-1在其中的作用

Effects of electroacupuncture on mitochondrial fusion and fission during intestinal injury in mice with endotoxemia and role of HO-1

目的评价电针对内毒素血症小鼠肠损伤时线粒体融合和分裂的影响及血红素氧合酶(HO-1)在其中的作用。方法SPF级健康雄性C57BL/6小鼠50只,8周龄,体重18~22 g,采用随机数字表法分为5组(n=10):对照组(C组)、内毒素血症组(E组)、内毒素血症+电针组(E+EA组)、内毒素血症+电针+氯化血红素组(E+EA+H组)和内毒素血症+电针+锌原卟啉Ⅸ组(E+EA+Znpp-Ⅸ组)。腹腔注射LPS 10 mg/kg建立小鼠内毒素血症模型。于注射LPS前,E+EA+H组腹腔注射HO-1诱导剂氯化血红素100 mg/kg,E+EA+Znpp-Ⅸ组腹腔注射HO-1抑制剂锌原卟啉Ⅸ10 mg/kg。于造模前4、3、2、1 d和30 min时,取合谷和足三里穴进行电刺激,刺激参数:疏密波,频率2 Hz/15 Hz,电流1 mA,刺激时间30 min,造模当天留针至实验结束。于造模后6 h处死小鼠,于回肠末端切取小肠组织,光镜下观察病理学结果,电镜下观察线粒体超微结构,测定ROS、ATP和二胺氧化酶(DAO)水平,采用Western blot法测定动力蛋白相关蛋白1(Drp1)、线粒体融合蛋白1(Mfn1)和HO-1的表达水平。结果与C组比较,E组小肠组织ROS水平升高,ATP含量和DAO活性降低,HO-1和Drp1表达上调,Mfn1表达下调(P<0.05),小肠组织发生病理学损伤;与E组比较,E+EA组小肠组织ROS水平降低,ATP含量和DAO活性升高,HO-1和Mfn1表达上调,Drp1表达下调(P<0.05),小肠组织病理学损伤减轻;与E+EA组比较,E+EA+H组小肠组织ROS水平降低,ATP含量和DAO活性升高,HO-1和Mfn1表达上调,Drp1表达下调(P<0.05),小肠组织病理学损伤减轻;E+EA+Znpp-Ⅸ组小肠组织ROS水平升高,ATP含量和DAO活性降低,HO-1和Mfn1表达下调,Drp1表达上调(P<0.05),小肠组织病理学损伤加重。结论电针可通过促进线粒体融合、抑制线粒体分裂,减轻内毒素血症小鼠肠损伤,其机制与上调HO-1的表达有关。

Objective To evaluate the effects of electroacupuncture(EA)on mitochondrial fusion and fission during intestinal injury in mice with endotoxemia and the role of heme oxygenase-1(HO-1).Methods Fifty SPF-grade healthy male C57BL/6 mice,aged 8 weeks,weighing 18-22 g,were divided into 5 groups(n=10 each)using a random number table method:control group(group C),endotoxemia group(group E),endotoxemia plus EA group(group E+EA),endotoxemia plus EA plus hemin group(group E+EA+H)and endotoxemia plus EA plus Znpp-Ⅸgroup(group E+EA+Znpp-Ⅸ).Lipopolysaccharide(LPS)was intraperitoneally injected to develop the model of endotoxemia.Before LPS injection,the HO-1 inducer hemin 100 mg/kg was intraperitoneally injected in group E+EA+H,and the HO-1 inhibitor zinc protoporphyrinⅨ10μmol/kg was intraperitoneally injected in group E+EA+Znpp-Ⅸ.At 4,3,2 and 1 days and 30 min prior to development of the model,Zusanli and Hegu acupoints were stimulated with electric stimulator(disperse-dense wave,frequency 2 Hz/15 Hz,at a voltage of 1 mA)for 30 min,retaining the needle until the end of the experiment on the day of development of the model.Mice were sacrificed at 6 h after development of the model,and the small intestinal tissue was obtained from the terminal ileum for examination of the pathological results(with a light microscope)and ultrastructure of mitochondria(with an electron microscope)and for determination of the levels of reactive oxygen species(ROS),ATP and diamine oxidase(DAO)and expression of dynamin-related protein 1(Drp1),mitofusin 1(Mfn1)and HO-1(by Western blot).Results Compared with group C,the level of ROS was significantly increased,ATP content and DAO activity were decreased,the expression of HO-1 and Drp1 was up-regulated,the expression of Mfn1 was down-regulated(P<0.05),and pathological damage to small intestine tissues was found in group E.Compared with group E,the level of ROS was significantly decreased,ATP content and DAO activity were increased,the expression of HO-1 and Mfn1 was up-regulated,the expression of Drp1 was down-regulated(P<0.05),and pathological damage to small intestine tissues was significantly attenuated in group E+EA.Compared with group E+EA,the level of ROS was significantly decreased,ATP content and DAO activity were increased,the expression of HO-1 and Mfn1 was up-regulated,the expression of Drp1 was down-regulated(P<0.05),and pathological damage to small intestine tissues was significantly attenuated in group E+EA+H,and the level of ROS was significantly increased,ATP content and DAO activity were decreased,the expression of HO-1 and Mfn1 was down-regulated,the expression of Drp1 was up-regulated(P<0.05),and pathological damage to small intestine tissues was accenuated in group E+EA+Znpp-Ⅸ.Conclusions EA can promote mitochondrial fusion,inhibit mitochondrial fission,and alleviate intestinal damage in mice with endotoxemia,and the mechanism is related to the up-regulation of HO-1 expression.