【作者】 孙轶； 杨慧敏； 廖国仪； 周冬； 余灵； 黄云祖； 周天鸿；

【Author】 Sun yi Huimin Yang Guoyi Liao Department of Pediatric,The First Affiliated Hospital,Jinan University Medical College,Guangzhou 510632,China

【机构】 暨南大学医学院第一附属医院儿科； 暨南大学生命科学技术学院；

【摘要】 目的:探讨叶酸缺乏对胎鼠宫内脑发育的影响,研究叶酸缺乏孕鼠子代脑组织基因组 DNA 甲基化水平的改变,为叶酸缺乏造成脑发育障碍提供分子水平的依据。方法:雌性 SD 大鼠实验组30只、对照组20只,分别饲以不含叶酸和含2mg 叶酸/kg 的纯合饲料,两周后与雄鼠交配,于怀孕第20天对孕鼠剖腹取胎。对模型进行评价并观察叶酸缺乏对胎鼠发育的影响,高效液相色谱法检测胎鼠脑组织基因组 DNA 甲基化水平。对孕鼠妊娠晚期末血清叶酸、胎鼠血清叶酸及胎鼠脑组织 DNA 甲基化水平作相关分析。结果:1.实验组孕鼠交配前及妊娠晚期末血清叶酸均明显低于对照组(p<0.01),外周血出现多分叶核粒细胞。实验组胎鼠血清叶酸也明显低于对照组(p<0.01).出现巨幼红细胞.RBC 和 HB 均低于对照组(p<0.01).且伴有宫内生长限制。2.实验组胎鼠脑组织基因组 DNA 甲基化水平低于对照组(p<0.05).这种改变与孕鼠及胎鼠本身的血清叶酸浓度呈正相关。结论:1.交配前两周开始限食叶酸直至妊娠期结束.所建立的叶酸缺乏孕鼠动物模型处于叶酸缺乏第三阶段.其胎鼠宫内生长限制.红细胞出现巨幼变,但没有产生神经管闭合的异常。这是较理想的妊娠中晚期叶酸缺乏的孕鼠动物模型。2.母体叶酸缺乏时胎鼠的脑组织基因组 DNA 甲基化水平降低.这种改变与孕鼠及胎鼠本身的血清叶酸浓度呈正相关.可能是母体叶酸缺乏时胎鼠脑发育障碍的机制之一。3.受孕前后增补叶酸宜延长至妊娠结束,以减少不良妊娠结局的危险。更多还原

【Abstract】 Purpose:To verify the effect of folate deficiency on fetal rats’ intrauterine brain development,the change of DNA methylation in fetal rats’ brain with maternal folate deficiency was studied.Our research was expected to provide some evidence on the aspect of DNA. Method:Female Sprague-Dawley rats,30 in the folate deficient group and 20 in the control group,received a purified diet without or with folate 2rag per Kg diet.After 14 d of feeding the rats were mated.The diets were continued throughout gestation.On day 20 of gestation the dams were killed,serum folate concentration was assayed and fetal development was observed.DNA methylation level in fetal brain was assayed by high performance liquid chromatography.Correlation analysis was processed among serum folate concentration of dam and fetus and DNA methylation level in fetal brain. Results:1.Dams in deficient group had significant lower serum folate concentration before mating or at the end of gestation than those in control group(p<0.01).Hypersegmented neutrophils were present in deficient group(p<0.01).Fetal serum folate concentration in this group was lower than those in control group too(p<0.01)and was associated with macrocyte and.2.The DNA methylation level in fetal brain in deficient group was also lower than that in control group(p<0.05),serum folate concentration of dams and fetus and DNA methylation level in fetal brain were positively correlated. Conclusion:1.Giving female SD rats folate-free diet from 2 weeks before mating to the end of gestation could produce an effective pregnant model which had folate deficiency at second and third trimesters of gestation.The fetal rats suffered macrocyte and intrauterine growth restriction,but didn’t have neural tube defect.2.The DNA methylation level in fetal rat’s brain decreased when it’s dam suffered folate deficiency.This kind of change was positively correlated with serum folate concentration of dams and fetus.It is possibly one of the mechanism of folate deficiency imparing the fetal rat’s brain development.3. Folate supplement during periconception should be prolonged to delivery.更多还原