肝脏过氧化物体增殖物激活受体γ基因启动子甲基化及其mRNA表达下调降低胎儿生长受限大鼠胰岛素敏感性  

DNA methylation of peroxisome proliferator-activated receptor promoter region and down-regulation ofits mRNA expression in liver decrease insulin sensitivity of fetal growth restricted rats

作　　者：邢燕[1] 齐婧[1] 王新利[1] 关育红[1] 张金[1] 童笑梅[1] 朴梅花[1] 

机构地区：[1]北京大学第三医院儿科,100191

出　　处：《中华围产医学杂志》2012年第11期683-688,共6页Chinese Journal of Perinatal Medicine

基　　金：国家自然科学基金青年基金（30901614）;教育部博士点基金新教师项目（20070001787）.

摘　　要：目的探讨肝脏过氧化物体增殖物激活受体7（peroxisomeproliferator—ativatedreceptor．y，PPAR7）基因启动子甲基化状态及其mRNA表达在胎儿生长受限（fetalgrowthrestriction，FGR）大鼠胰岛素敏感性降低中的作用。方法20只雌鼠受孕后第1天随机分为对照组和低蛋白组，各10只。低蛋白组采用低蛋白（粗蛋白含量为8．OO％）法建立FGR模型。测定对照组仔鼠和低蛋白组FGR仔鼠生后3、7、14、30、60及90d（每组每个时间点取雄性仔鼠8只）空腹血浆血糖和空腹血清胰岛素，计算胰岛素抵抗指数及胰岛素敏感指数。采用甲基化特异性聚合酶链反应和逆转录一聚合酶链反应技术测定仔鼠生后7和90d时肝脏组织PPAR3＇基因启动子甲基化水平及其mRNA表达情况。采用Pearson相关分析及秩和检验分析肝脏组织中PPAR3＇基因启动子甲基化及其mRNA表达改变与胰岛素敏感性变化间的关系。结果（1）低蛋白组新生仔鼠平均出生体重为（4．92±0．36）g，低于对照组的（6．43±0．59）g（t=14．73，P〈0．05）。低蛋白组仔鼠中FGR发生率为88．2％（97／110），其中雄性仔鼠FGR发生率为94．1％（48／51）。（2）生后90d时FGR仔鼠空腹血浆血糖、血清胰岛素和胰岛素抵抗指数显著高于对照组[空腹血浆血糖：（8．95±1．83）mmol／L与（6．21±1．14）mmol／L，t=-3．291，P〈0．05；血清胰岛素：（59．57±9．89）mU／L与（36．10±7．32）rnU’／L，t=-4．916，P〈0．05；胰岛素抵抗指数：0．967±0．297与0．410士0．135，t=-4．472，P〈0。05）]，而胰岛素敏感指数低于对照组仔鼠（-3．043±0．294与-2．172±0．354，t=4．774，P〈0．05）。（3）生后7d时，对照组仔鼠与FGR仔鼠PPAR3＇基因启动子甲基化程度差异无统计学意义（0／8与2／8，Fisher精确概率法，P〉0．05），生后90d时FGR仔鼠甲基化程度高于对照组仔鼠（8／8与2／8，Fisher�Objective To explore the effect of methylation ot peroxlsome prolllerator-acnvatecl receptor 7 （PPART） gene promoter in liver and its mRNA expression changes on decreasing of insulin sensitivity in feta[ growth restriction （FGR） rats. Methods Twenty pregnant rats were randomly divided into two groups on their first day of pregnancy., normal-protein group （NP） and low-protein group （LP）, ten in each. During pregnancy the LP group rats were fed with low-protein diet （8.00%protein）, while the NP group rats were fed with normal-protein diet （20.00% protein）. The offspring rats were fed with standard feed after 21 days of birth. Male offsprings in NP group were as control offsprings, and male FGR offsprings in LP group ware as FGR offsprings. At day 3, 7, 14, 30, 60 and 90, fasting blood of offsprings was collected to measure fasting plasma glucose （FPG） and fasting insulin（FINS）. Then insulin resistance index of homeostasis model assessment （HOMA 1R） and insulin sensitivity index （ISI） were calculated to evaluate insulin sensitivity. At day 7 and 90, liver tissue of male offsprings was collected to extract DNA and total RNA. The methylation level of PPARy gene promoter and its mRNA expression were detected by methylation specific-polymerase chain reaction （MS-PCR） and reverse transcription-RCR, respectively. The relationships between methylation of PPARy gene promoter and mRNA expression and insulin sensitivity were analyzed by Pearson correlation and nonparametric test method. Results （1） The mean offspring birth-weight of LP group was （4.92±0.36） g, which was lower than that [（6.43±0.59） g] of control group （t= 14.73, P〈0.05）. In LP group, the incidence of FGR offspring was 88.2% （97/110） and the FGR incidence of male ones was 94.1± （48/51）. （2） At day 90, compared with control offsprings, FPG [（8.95±1.83） mmol/L vs （6.21±1.14） mmol/L, t=-3.291, P〈0.05], FINS [（59.57±9.89） mU/Lvs （36.10%7.32） mU/L, 1=-4.916, P〈0.059

关 键 词：胎儿生长迟缓 胰岛素抗药性 PPAR DNA甲基化 

分 类 号：R714.2[医药卫生—妇产科学]