上皮间质转化在油雾颗粒物诱导心肌纤维化中的作用

Effect of epithelial-mesenchymal transition on cardiac fibrosis induced by oil mist particulate matter

目的:探讨油雾颗粒物(OMPM)暴露对大鼠心肌组织的损伤,以及上皮间质转化(EMT)在其损伤中的作用。方法:6周龄Wistar大鼠(雌雄各半)随机分为3组:对照组(不施加OMPM暴露)、低剂量暴露组(50 mg/m^(3))、高剂量暴露组(100 mg/m^(3)),每组18只。每日进行动态吸入暴露染毒6.5 h。连续暴露42 d后,每组均取心脏组织进行形态学观察;蛋白印迹法(Western blot)检测心脏纤维化标志物胶原蛋白Ⅰ(CollagenⅠ)、胶原蛋白Ⅲ(CollagenⅢ)表达水平,上皮标志物E-钙黏蛋白(E-Cadherin)表达水平,间质标志物N-钙黏蛋白(N-Cadherin)、纤连蛋白(Fibronectin)、波形蛋白(Vimentin)、α平滑肌肌动蛋白(α-SMA)表达水平,以及转录因子Twist蛋白表达水平;实时荧光定量聚合酶链反应(RT-qPCR)检测CollagenⅠ、CollagenⅢ基因表达水平。结果:OMPM暴露后,随着暴露剂量增加,大鼠心肌细胞水肿,胶原纤维沉积逐渐增加。Western blot结果显示,与对照组比较,OMPM暴露组CollagenⅠ、CollagenⅢ、N-Cadherin、Fibronectin、Vimentin、α-SMA、Twist蛋白表达水平显著升高(P<0.01),且高剂量暴露组蛋白表达水平显著高于低剂量暴露组(P<0.01);OMPM暴露组E-Cadherin蛋白表达水平显著降低,且高剂量暴露组蛋白表达水平显著低于低剂量暴露组(P<0.01)。RT-qPCR结果显示,OMPM暴露组CollagenⅠ、CollagenⅢmRNA表达水平显著高于对照组(P<0.01),且高剂量暴露组mRNA水平显著高于低剂量暴露组(P<0.01)。结论:OMPM通过促进EMT过程诱导大鼠心脏纤维化。

Objective:To investigate the effects of oil-mist particulate matter(OMPM)on cardiac tissue structure fibrosis in rats and the role of epithelial-mesenchymal transition(EMT).Methods:Six-week-old Wistar rats(half male and half female)were randomly divided into 3 groups:control group(without OMPM exposure),low-dose exposure group(50 mg/m ^(3))and high-dose exposure group(100 mg/m ^(3)),18 rats in each group,with 6.5 hours per day of dynamic inhalation exposure.After 42 days of continuous exposure,cardiac tissues were collected for morphological observation;Western blot was used to detect fibrosis markers collagen I and collagen III levels,epithelial marker E-cadherin levels,interstitial markers N-cadherin,fibronectin,vimentin,alpha-smooth muscle actin(α-SMA)levels,and EMT transcription factor Twist protein levels;Real-time polymerase chain reaction(RT-qPCR)was used to detect collagen I and collagen III mRNA levels.Results:After OMPM exposure,myocardial cell edema and collagen fiber deposition were increased gradually with increasing exposure dose.Western blot results showed that compared with the control group,the expression levels of collagen I,collagen III,N-Cadherin,fibronectin,vimentin,α-SMA,and Twist protein were increased significantly in the low-dose exposure group and the high-dose exposure group(P<0.01),and protein expression levels were higher in the high-dose exposure group than those in the low-dose exposure group(P<0.01).In contrast,E-Cadherin protein expression levels were decreased significantly,and lower in the high-dose exposure group(P<0.01).RT-qPCR results showed that compared with the control group,collagen I and collagen III mRNA levels were increased significantly in the low-dose exposure group and the high-dose exposure group(P<0.01),and were increased with increasing exposure dose.(P<0.01).Conclusion:OMPM may induce cardiac fibrosis in rats by promoting EMT process.