肌肉因子irisin在舒张性心力衰竭大鼠中的表达及意义

Expression of myokine irisin in experimental model of diastolic heart failure

目的通过建立大鼠压力负荷诱导舒张性心力衰竭模型,探索新型肌肉因子irisin与舒张性心力衰竭(diastolic dysfunction,DHF)之间的联系,为临床应用提供依据。方法采用腹主动脉缩窄(abdominalaortic constriction,AAC)的手术方式建立压力负荷诱导大鼠DHF的疾病模型。20只SD大鼠随机分入AAC手术组(n=10)和假手术(sham)组(n=10)。造模12周后测量心超、心室内压力、解剖结构评估造模效果。EILSA检测irisin两组间血清水平表达差异;利用Real-time PCR、Western印迹法、免疫组化染色分析irisin的剪切前体Ⅲ型纤维蛋白结构域5(FNDC5)在两组间表达差异,寻找irisin的分泌来源。结果成功建立AAC-DHF的SD大鼠疾病模型。造模12周时,AAC组大鼠血清irisin水平逐渐升高,第12周时显著高于Sham组[(135.2±28.9)ng/ml vs(64.9±34.0)ng/ml,P<0.001]。Real-time PCR结果显示,FNDC5在AAC组的心脏组织(11.8±2.4 vs 1.88±1.2,P<0.001)和肌肉组织中表达较高(15.1±1.6 vs 1.25±1.4,P<0.001)。Western印迹法显示,AAC组FNDC5在心脏表达高于Sham组(P=0.021)。IHC染色显示,FNDC5主要表达于AAC组骨骼肌筋膜和心肌实质。结论大鼠AAC模型证实血清irisin水平在DHF的情况下升高,其来源可能是由心肌和骨骼肌共同分泌的。

Objective To establish an after-load pressure induced rat model of heart diastolic dysfunction and to investigate its relationship with newmyokine irisin. Methods The abdominal aortic constriction（ AAC） was used to establish an animal model of pressure over-load induced diastolic dysfunction in rat. Twenty Sprague-Dawley（ SD） rats were divided into AAC group（ n = 10）and sham group（ n = 10）. Echocardiography,interventricular pressure,heart structure analysis were used to confirm the model. Q-PCR,Western blot and immunohistochemistry assays（ IHC） were used to analyze the expression level of splice-precursor（ FNDC5） of irisin. Results ELISA analysis showed that irisin level were significant higher in AAC group than that in sham group [（ 135. 2 ± 28. 9） ng / ml vs（ 47. 5 ±16. 0） ng /ml,P〈 0. 001]. Q-PCR results showed that FNDC5 m RNA relative expression level was higher in hypertrophic myocardium（ 11. 8 ± 2. 4 vs 1. 88 ± 1. 2,P 〈0. 001） and skeletal muscle（ 15. 1± 1. 6 vs 1. 25 ± 1. 4,P〈0. 001） of AAC group than those of sham group. Western blotting results showed FNDC5 protein expression in myocardium of AAC group was higher than that of sham group（ P =0. 021）. IHC result showed that the AAC rat had a significant higher FNDC5 protein IHC staining in skeletal muscle and cardiac muscle compared with sham group. Conclusion The SD rat model of AAC-DHF confirms that serum irisin level is increased in pressure-induced left ventricular diastolic dysfunction,and irisin may be produced by myocardium and skeletal muscle.