摘要
目的:探讨表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)能否预防老年小鼠心肌肌钙蛋白Ⅰ(cardiac troponinⅠ,cTnⅠ)表达下降,并研究其机制。方法:随机选取3、12、14、16和18月龄小鼠各5只,用RT-PCR、Western blot检测心脏中cTnⅠmRNA和蛋白质表达。12月龄小鼠32只随机分为空白组、EGCG低剂量组[EGCG-L,50 mg/(kg·d)]、EGCG中剂量组[EGCG-M,100 mg/(kg·d)]和EGCG高剂量组[EGCG-H,200 mg/(kg·d)],每组8只,通过饮水摄入EGCG持续干预6个月,3月龄小鼠为青年组(n=8)。RT-PCR检测cTnⅠ和HDAC1 mRNA表达,Western blot检测cTnⅠ蛋白质表达,CHIP-Q-PCR检测cTnⅠ启动子区H3K9乙酰化水平和HDAC1、GATA4、Mef2c结合水平。结果:小鼠衰老过程中,与12月龄[(1.483±0.226),(1.127±0.074)]比较,cTnⅠmRNA和蛋白质表达在16月龄[(0.913±0.150),(0.683±0.133)]时开始下降(P=0.002,P=0.003)。EGCG干预后,与空白组[(1.924±0.117),(0.963±0.105)]比较,EGCG-H组[(0.801±0.037),(0.225±0.153)]中HDAC1 mRNA表达和结合水平下降(均P=0.000)。空白组中cTnⅠ启动子区H3K9乙酰化,GATA4和Mef2C的结合水平分别为(0.392±0.138)、(0.404±0.150)、(0.347±0.093),EGCG-H组中H3K9乙酰化(0.723±0.208)和GATA4(1.051±0.239)、Mef2c(1.129±0.187)的结合水平均升高(P=0.014,P=0.000,P=0.000)。EGCG-H组[(0.943±0.114),(1.034±0.058)]中cTnⅠmRNA和蛋白质与空白组[(0.093±0.033),(0.619±0.179)]比较表达升高(P=0.000,P=0.007)。结论:高剂量EGCG通过抑制HDAC1,升高H3K9乙酰化预防老年小鼠心脏中cTnⅠ表达下降。
Objective：To investigate whether epigallocatechin gallate（EGCG） could prevent the declining expression of cardiac tro- ponin Ⅰ （cTn Ⅰ ） in aging mice hearts and to study its mechanism. Methods ：Expression levels of cTnⅠ mRNA and protein were detected by using RT-PCR and Western blot assays in each age group（n=5）. A total of 32 C57 BL/6 female mice of 12 month old were randomly divided into the blank group,the EGCG low-dose group[EGCG-L,50 mg/（kg·d）],the EGCG medium-dose group[EGCG- M, 100 mg/（kg·d）] and the EGCG high-dose group[EGCG-H,200 mg/（kg·d）]. Mice from EGCG intervention groups were treated with EGCG by water for 6 months. The female mice at age of 3-month were chosen as the young group（n=8）. The eTn I and HDAC1 mRNA expression were measured by RT-PCR. The protein level of cTn I was determined by Western blot. The binding level of aeetylated lysine 9 on histone H3（AcH3K9）,HDAC1 ,transcription factors GATA4 and Mef2c near cTn I＇s promoter was identified by CHIP-Q-PCR. Results：During the aging process,both expressive levels of cTn I mRNA and protein of 16-month-old mice [（0.913 ± 0.150）, （0.683 ± 0.133）] began decreasing（P=0.002, P=0.003） when compared with 12-month-old mice[（1.483± 0.226）, （1.127± 0.074）]. After EGCG intervention,the HDAC1 expression and the binding level in cTn I＇s promoter region in the EGCG-H group[（0.801 ± 0.037）, （0.225 ± 0.153）] were lower than those in the blank group[ （ 1.924 ± 0.117 ）, （0.963 ± 0.105 ） ]（P=0.000,P=0.000）. AcH3K9 levels in cTn I＇s promoter region and binding levels of GATA4 and Mef2c were （0.392 ±0.138）, （0.404±0.150）, （0.347 ±0.093） ,respectively. In the EGCG-H gronp,AcH3K9 levels（0.723 ± 0.208）, GATA4（1.051±0.239） and Mef2c （ 1.129± 0.187） binding levels in the proximal promoter region of eTnⅠ gene were increased （P=0.014, P=0.000, P=0.000）. Expressive levels of cTn Ⅰ mRNA and protein in the EGCG-H group[（0.943± 0.114）, （1.034±0.058）] were higher than those in the blank group[（0.093 ±0.033）, （0.619 ± 0.179）]（P=0.000,P=-0.007）. Conclusion：High dose EGCG can prevent the decline of cTn I in aging mice by inhibiting HDAC1 and elevating AcH3K9.
作者
贾忠莉
全珺珺
潘博
刘玲娟
田杰
Jia Zhongli;Quan Junjun;Pan Bo;Liu Lingjuan;Tian Jie(Department of Cardiology, Children＇ s Hospital of Chongqing Medical University, Children＇ s Development and Disorders Key Laboratory of Ministry of Education, International and National Science and Technology Cooperation Base of Children Development and Critical Disorders, Chongqing Key Laboratory of Pediatric)
出处
《重庆医科大学学报》
CAS
CSCD
北大核心
2018年第3期332-338,共7页
Journal of Chongqing Medical University
基金
国家自然科学基金面上资助项目(编号:81670212)
