[大鼠心肌梗死后心肌微小RNA-30a表达与心肌纤维化的关系]
[Relationship between myocardial microRNA-30a expression and myocardial fibrosis in rats post myocardial infarction].
作者信息
Chen L W, Zhu L L, Ji Q, Zhu H, Ren Y Z, Fan Z G, Li X B, Gao X F, Zhang Y J, Tian N L
机构信息
Department of Cardiology, Nanjing Hospital Affiliated to Nanjing Medical University, Nanjing 210006, China.
出版信息
Zhonghua Xin Xue Guan Bing Za Zhi. 2016 May 24;44(5):443-9. doi: 10.3760/cma.j.issn.0253-3758.2016.05.015.
OBJECTIVE
To explore the potential role and mechanism of microRNA(miR)-30a in myocardial fibrosis after myocardial infarction (MI).
METHODS
Rats were randomly divided into 1 week MI group (n=11), 2 weeks MI group (n=13) and 4 weeks MI group (n=15) by applying random number table after left anterior descending coronary artery ligation. Rats in Sham group were examined at respective time points (n=16). Heart function was monitored by echocardiography. Myocardial collagen volume fraction (CVF) was determined on Masson stained sections. Myocardial expression of collagen Ⅰ and Ⅲ was determined by immunohistochemistry. The myocardial mRNA level of miR-30a, TGF-β1 and CTGF were detected by real time-quantitative PCR analysis. The myocardial protein levels of TGF-β1 and CTGF were measured by Western blot analysis.
RESULTS
The LVEDD ((8.37±0.58) mm) and LVESD ((6.12±0.82) mm) in 4 weeks MI group were significantly higher than those in Sham group ((6.08±0.57) mm, (4.17±0.60) mm), all P<0.01. The FS ((27.0±3.9) %) and LVEF ((51.0±6.3) %) in 4 weeks MI group were significantly lower than those in Sham group ((47.0±2.1) %, (82.0±2.3)%), all P<0.01. The level of myocardial CVF in 1 week MI group, 2 weeks MI group and 4 weeks MI group were significantly higher than in Sham group (all P<0.01) in a time-dependent manner. The level of myocardial collagen Ⅰ and Ⅲ was increased gradually from 1 week to 4 weeks post MI compared with Sham group (all P<0.01). The collagen Ⅰ/Ⅲ ratio was similar between 1 week MI group and Sham group (P=0.58), however, which was significantly higher in 2 weeks MI group and 4 weeks MI group compared with Sham group (all P<0.01), and the ratio was significantly higher in 4 weeks MI group than 2 weeks MI group (P<0.01). The level of miR-30a was significantly and gradually reduced in all MI groups compared with Sham group (all P<0.01). The mRNA and protein levels of TGF-β1 and CTGF were significantly and gradually increased after MI compared with Sham group (all P<0.001).
CONCLUSIONS
Our results indicate that overexpression of miR-30a after MI might be a potential strategy for suppressing myocardial fibrosis by modulating the mRNA and protein levels of TGF-β1 and CTGF.
目的
探讨微小RNA（miR）-30a在心肌梗死（MI）后心肌纤维化中的潜在作用及机制。
方法
采用随机数字表法将大鼠在左冠状动脉前降支结扎后随机分为1周MI组（n = 11）、2周MI组（n = 13）和4周MI组（n = 15）。假手术组大鼠在相应时间点进行检查（n = 16）。通过超声心动图监测心功能。在Masson染色切片上测定心肌胶原容积分数（CVF）。通过免疫组织化学法测定心肌Ⅰ型和Ⅲ型胶原的表达。通过实时定量PCR分析检测miR-30a、转化生长因子-β1（TGF-β1）和结缔组织生长因子（CTGF）的心肌mRNA水平。通过蛋白质印迹分析测定TGF-β1和CTGF的心肌蛋白水平。
结果
4周MI组的左室舒张末期内径（（8.37±0.58）mm）和左室收缩末期内径（（6.12±0.82）mm）显著高于假手术组（（6.08±0.57）mm，（4.17±0.60）mm），所有P<0.01。4周MI组的左室短轴缩短率（（27.0±3.9）%）和左室射血分数（（51.0±6.3）%）显著低于假手术组（（47.0±2.1）%，（82.0±2.3）%），所有P<0.01。1周MI组、2周MI组和4周MI组的心肌CVF水平均显著高于假手术组（所有P<0.01），且呈时间依赖性。与假手术组相比，MI后1周至4周心肌Ⅰ型和Ⅲ型胶原水平逐渐升高（所有P<0.01）。1周MI组和假手术组之间的Ⅰ/Ⅲ型胶原比值相似（P = 0.58），然而，与假手术组相比，2周MI组和4周MI组的该比值显著更高（所有P<0.01），且4周MI组的比值显著高于2周MI组（P<0.01）。与假手术组相比，所有MI组中miR-30a水平均显著且逐渐降低（所有P<0.01）。与假手术组相比，MI后TGF-β1和CTGF的mRNA和蛋白水平显著且逐渐升高（所有P<0.001）。
结论
我们的结果表明，MI后miR-30a的过表达可能是通过调节TGF-β1和CTGF的mRNA和蛋白水平来抑制心肌纤维化的一种潜在策略。
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