七氟烷对大鼠肺动脉高压致右心室心肌纤维化的影响

Effects of sevoflurane on right ventricular myocardial fibrosis induced by pulmonary arterial hypertension in rats

目的评价七氟烷对肺动脉高压大鼠右心室心肌纤维化的影响。方法SPF级健康成年雄性Wistar大鼠18只,体重260~300 g,采用随机数字表法分为3组(n=6):对照组(C组)、肺动脉高压组(PAH组)和肺动脉高压+七氟烷组(PS组)。PAH组及PS组腹腔注射野百合碱60 mg/kg制备肺动脉高压模型,C组腹腔注射等容量生理盐水。PS组注射完毕后吸入1.5 MAC七氟烷1 h,2次/周,共6周。于第6周末行心脏超声检查,测量右心室舒张末期前后径(RVEDD)、右心室前壁舒张末期厚度(RVWTd)、室间隔舒张末期厚度(IVSTd)、肺动脉内径(PAID)及肺动脉瓣口最大峰值流速(PV)。于第6周末取大鼠心脏,称量右心室、室间隔和左心室重量,计算Fulton′s指数;取右肺下叶组织,HE染色后测量血管壁外径和血管壁内径,计算血管壁厚度指数(WT),测量总血管面积和管腔面积,计算管壁面积指数(WA)。取右心室心肌组织,行Masson染色,光镜下观察右心室心肌纤维化程度;行免疫荧光染色,观察右心室心肌组织TGF-β1的表达情况;采用Western blot检测右心室心肌组织转化生长因子β1(TGF-β1)、磷酸化Smad3(p-Smad3)和Smad7的表达水平。结果与C组相比,PAH组Fulton′s指数、RVEDD、RVWTd、IVSTd、PAID、WT和WA升高,PV降低,右心室心肌组织TGF-β1和p-Smad3表达上调,Smad7表达下调(P<0.01),发生心肌纤维化。与PAH组相比,PS组Fulton′s指数、RVEDD、RVWTd、IVSTd、PAID、WT和WA降低,PV升高,右心室心肌组织TGF-β1和p-Smad3表达下调,Smad7表达上调(P<0.05或0.01),心肌纤维化明显改善。结论七氟烷可改善大鼠肺动脉高压致右心室心肌纤维化,其机制可能与抑制TGF-β1/Smad3信号通路激活有关。

Objective To evaluate the effects of sevoflurane on right ventricular myocardial fibrosis caused by pulmonary arterial hypertension(PAH)in rats.Methods Eighteen SPF healthy adult male Wistar rats,weighing 260-300 g,were divided into 3 groups(n=6 each)by a random number table method:control group(group C),group PAH and PAH plus sevoflurane group(group PS).The PAH model was established by single intraperitoneal injection of monocrotaline 60 mg/kg in group PAH and group PS,while the equal volume of normal saline was intraperitoneally injected in group C.Sevoflurane 1.5 MAC was inhaled for 1 h starting from the end of injection,twice a week for 6 weeks in total,in group PS.Echocardiography was performed at the end of 6th week to measure right ventricular end-diastolic diameter(RVEDD),right ventricular anterior wall end-diastolic thickness(RVWTd),interventricular septal end-diastolic thickness(IVSTd),pulmonary artery inner diameter(PAID)and pulmonary valve orifice maximum peak velocity(PV).At the end of 6th week,the hearts were taken to measure the weight of right ventricle,interventricular septum and left ventricle,and Fulton′s index was calculated,and the tissue of the lower lobe of the right lung was taken,the outer diameter and inner diameter of the vascular wall were measured to calculate the vascular wall thickness index(WT),and total vascular area and lumen area were measured to calculate the vascular wall area index(WA)after HE staining.The myocardial tissue of the right ventricle was obtained to observe the degree of myocardial fibrosis(with a light microscope after Masson staining)and to detect the expression of TGF-β1(after immunofluorescence staining)and expression of TGF-β1,phosphorylated Smad3(p-SMad3)and Smad7(by Western blot).Results Compared with group C,Fulton′s index,RVEDD,RVWTd,IVSTd,PAID,WT and WA were significantly increased,PV was decreased,the expression of TGF-β1 and pSmad3 in right ventricular myocardial tissues was up-regulated,the expression of Smad7 was down-regulated(P<0.01),and myocardial fibrosis occurred in group PAH.Compared with group PAH,Fulton′s index,RVEDD,RVWTd,IVSTd,PAID,WT and WA were significantly decreased,PV was increased,the expression of TGF-β1 and pSmad3 in right ventricular myocardial tissues was down-regulated,the expression of Smad7 was up-regulated(P<0.05 or 0.01),and myocardial fibrosis was significantly improved in group PS.Conclusion Sevoflurane can improve the myocardial fibrosis in right ventricle induced by PAH in rats,and the mechanism may be related to inhibiting activation of TGF-β1/Smad3 signaling pathway.