丹皮酚对大鼠急性心肌梗死所致心肌纤维化的影响及机制

Effect and Mechanism of Paeonol on Myocardial Fibrosis Induced by Myocardial Infarction in Rats

目的:观察丹皮酚(paeonol,Pae)对大鼠急性心肌梗死(acute myocardial infarction,AMI)所导致的心肌纤维化的干预作用,并研究其作用机制是否与Pae影响心肌组织中转化生长因子-β1(transforming growth factor-β1,TGF-β1),Smad 2 RNA及蛋白含量的表达有关。方法:采用左冠状前降支(LAD)结扎法制作大鼠急性心肌梗死模型,以心电图出现ST段水平向下或向上偏移≥0.1 m V且T波高耸超过同导联R波的1/2、左室前壁颜色变苍白视为心肌梗死(MI)模型成功,将造模成功的大鼠随机分为模型组、丹皮酚低、高剂量组,另有只穿线不结扎的假手术组,共4组,丹皮酚低、高剂量组分别给予ip 8.0,12.0mg·kg-1剂量的丹皮酚注射液,假手术组与模型组每天ip等体积生理盐水,每天给药1次;28 d后取材,检测左心指数;HE染色,Masson染色分别观察心肌组织病理生理学改变及心肌间质纤维化情况,实时荧光定量RT-PCR和Western blotting法分别检测左室梗死区TGF-β1,Smad2的mRNA和蛋白表达。结果:左心指数:与假手术组比较,模型组左心指数明显升高(P<0.01);与模型组比较,丹皮酚8.0,12.0 mg·kg-1组左心指数均下降(P<0.01,P<0.05);HE染色结果显示:与假手术组比较,模型组大鼠左室病理生理学改变显著,梗死边缘部分心肌细胞发生肥大、伸长、左心室壁部分心肌凝固性坏死,凋亡细胞胞核固缩,胞质伊红深染,另有部分发生疏松水肿,与模型组比较,丹皮酚8.0,12.0 mg·kg-1组病理改变均不同程度减轻;Masson染色结果显示:与假手术组比较,模型组大鼠心肌胶原纤维明显增多,纤维瘢痕形成,心肌纤维化程度较重,与模型组比较,丹皮酚8.0,12.0 mg·kg-1组大鼠心肌纤维化程度均不同程度减轻;与假手术组比较,模型组TGF-β1,Smad 2 mRNA和蛋白的相对表达量均增多(P<0.01);与模型组比较,丹皮酚8.0,12.0 mg·kg-1组TGF-β1,Smad 2 mRNA和蛋白表达均降低(P<0.01)。结论:Pae具有抗急性心肌梗死所致大鼠心肌纤维化的作用,其机制可能与其干预TGF-β1/Smad2信号通路的传导有关。

Objective： To study the effect of paeonol （Pae） on myocardial fibrosis in rats with acute myocardial infarction （AMI） and to investigate whether its mechanism is related to the expression of transforming growth factor-β1 （TGF-β1）, Smad2 mRNA and protein. Method： In vivo model of AMI was made using the ligation of left anterior descending coronary branch. The successful myocardial infarction （MI） modeling was based on the following changes like electrocardiogram （ECG） ST segment level downward or upward shift 〉10. 1 mV and T wave towering over with R wave of 1/2, left ventricular anterior turned pale. The rats were randomly divided into the model group, the sham group, the low-, high-dose Pae groups （8.0, 12.0 mg ·kg^-1）. The sham group and model group were given ip volume of saline daily. The left ventricular indexed were measured after 4 weeks. The pathology of myocardial tissue was observed by HE staining, the level of myocardial interstitial fibrosiswas observed by Masson staining. The mRNA expression levels of TGF-β1, Smad 2 in myocardial tissueswere detected using real-time quantitative PCR （RT-PCR） technique. Result： Compared with the sham group, he left cardiac index was significantly higher （P 〈0.01 ） in the model group. Compared with the model group, the left cardiac index was decreased （P 〈 0.01, P 〈 0.05） in all does Pae groups. HE staining showed that compared with the sham group pathological changes were significantly in the model group, there were cardiac hypertrophy, elongation and coagulation necrosis in injured myocardial hypertrophy edge part, while some loose edema occurred in left ventricular myocardial wall portion. Compared with the model group, the pathological changes were decreased. Masson staining showed that compared with the sham group, collagen fibers increased significantly in model group, and there appeared fiber epilepsy marks, and also severe myocardial fibrosis, Compared with the model group, the level of myocardial fibrosis in all dose Pae groups were decreased. Compared with the sham group, TGF-β1, Smad 2 mRNA and protein expression levels were significantly increased （P 〈 0.05） ; compared with the model group, the TGF-β1, Smad 2 mRNA and protein expression level were decreased （P 〈 0.01 ） in all dose Pae groups. Conclusion： Pae has anti-myocardial fibrosis effect in AMI rats. Its mechanism may be related to the intervention of TGF-β1/Smad2 signaling pathways.