microRNA-1抑制心肌特异性Dicer基因缺失小鼠心脏病理性重构

发布时间：2018-02-16 05:53

本文关键词： Dicer 心力衰竭 microRNA- 心脏重构　出处：《第三军医大学学报》2017年14期 　论文类型：期刊论文

【摘要】：目的探讨microRNA-1(miR-1)对他莫昔芬(tamoxifen,TMX)诱导的心肌特异性Dicer基因缺失小鼠心脏结构重构及心功能的影响。方法采用Myh6-Cre/Loxp重组系统,通过Dicerloxp/loxp小鼠和Myh6-cre ERT小鼠杂交,获得Myh6-cre ERT/Dicerloxp/loxp小鼠。将18只8周龄雄性Myh6-cre ERT/Dicerloxp/loxp小鼠按随机数字表法分为对照组、模型组、miR-1治疗组。采用腹腔注射20 mg/mL TMX溶液(0.1 mL),连续注射5 d,建立心肌特异性Dicer基因缺失心力衰竭小鼠模型,对照组腹腔注射玉米油;模型建立后,miR-1治疗组通过尾静脉注射miR-1类似物(miR-1 mimic)10 nmol/只,对照组给予同等剂量生理盐水,模型组给予miRNA阴性对照试剂,2次/周。1周后,经胸二维超声心动图检测各组小鼠舒张末期左室内径(LVIDd)、收缩末期左室内径(LVIDs)、舒张末期左室容积(EDV)、收缩末期左室容积(ESV)、射血分数(EF)及左室短轴缩短率(FS),然后收集心肌标本,通过HE染色、Masson三色染色及天狼猩红染色观察小鼠心肌结构重构程度;利用原位缺口末端标记法(terminal deoxynucleotidyl transferase-mediated d UTP nick-end labeling,TUNEL)免疫荧光染色检测心肌组织细胞凋亡情况;通过细胞增殖指标Ki67免疫组化染色评估细胞增殖水平。结果建模后1周,模型组小鼠心功能明显下降,LVIDs及ESV均高于对照组(P0.05),EF及FS则显著低于对照组(P0.05),miR-1治疗后上述指标均较模型组明显改善(P0.05)。组织病理学检测结果显示,与对照组相比,模型组小鼠心肌细胞排列紊乱,细胞肥大,炎症细胞浸润明显,心肌纤维化显著,而治疗组小鼠心肌细胞形态正常,无明显肥大和炎性浸润,未见明显的间质纤维化;TUNEL免疫荧光染色及Ki67免疫组化染色结果显示,miR-1治疗组小鼠较模型组心肌组织凋亡比例增加(P0.05),且存在较明显的细胞增殖(P0.05)。结论 miR-1可抑制TMX诱导的心肌特异性Dicer基因缺失心力衰竭模型中心肌细胞的固有改变和间质的改变,抑制心脏结构重构,维持心功能。
[Abstract]:Objective to investigate the effects of microRNA-1 miR-1 on cardiac structural remodeling and cardiac function in mice with myocardial specific Dicer gene deletion induced by tamoxifenn (TMX). Methods using Myh6-Cre/Loxp recombination system, Dicerloxp/loxp mice and Myh6-cre ERT mice were hybridized. Myh6-cre ERT/Dicerloxp/loxp mice were obtained. Eighteen 8-week-old male Myh6-cre ERT/Dicerloxp/loxp mice were randomly divided into control group. In the model group, the mice model of heart failure with myocardial specific Dicer gene deletion was established by intraperitoneal injection of 20 mg/mL TMX solution 0. 1 mL / L for 5 days, and the control group was injected with corn oil intraperitoneally. After the establishment of the model, the treatment group was injected with miR-1 analogue mimic)10 nmol-1 via tail vein, the control group was given the same dose of normal saline, and the model group was treated with miRNA negative control reagent twice a week. The left ventricular dimension (LVIDdN), left ventricular dimension (LVIDsN), left ventricular volume (EDV), left ventricular volume (ESVV), ejection fraction (EFF) and the shortening rate of left ventricular short axis were measured by transthoracic two-dimensional echocardiography in each group, and the myocardial specimens were collected. The degree of myocardial remodeling was observed by HE staining and Sirius red staining, and the apoptosis of cardiac myocytes was detected by terminal deoxynucleotidyl transferase-mediated d UTP nick-end Tunel staining. The level of cell proliferation was evaluated by Ki67 immunohistochemical staining. LVIDs and ESV in the model group were significantly lower than those in the control group compared with the control group. The results of histopathological examination showed that, compared with the control group, the above indexes were significantly improved. In the model group, the cardiac myocytes were arranged disorderly, the cells were hypertrophic, inflammatory cells infiltrated obviously, and myocardial fibrosis was obvious, but in the treatment group, the cardiac myocytes were normal in shape and had no obvious hypertrophy and inflammatory infiltration. The results of Tunel immunofluorescence staining and Ki67 immunohistochemical staining showed that the apoptosis ratio of myocardial tissue in the treatment group was higher than that in the model group, and there was a significant proliferation of P0.05G in the model group. Conclusion miR-1 can inhibit TMX. The intrinsic changes of cardiac myocytes and interstitial changes in heart failure model induced by myocardial specific Dicer gene deletion. Inhibition of cardiac structural remodeling and maintenance of cardiac function.
【作者单位】：重庆医科大学附属第二医院心内科;四川大学华西医院病理研究室;
【分类号】：R541.6

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