叶酸缺乏孕鼠子代血细胞形态学改变及脑额区皮层超微结构表现

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胎鼠脑组织超微结构的改变及为叶酸缺乏造成脑发育障碍提供细胞水平的依据 ,及采用雌性SD大鼠实验组 30只、对照组 2 0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 2 0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 ,应用透射电镜观察胎鼠额区皮层超微结构的改变。结果显示 :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 ,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 ,出现巨幼红细胞 ,RBC和HB均低于对照组 ,且伴有宫内生长限制。 2 .实验组胎鼠额区皮层超微结构观察示 :神经元出现核切迹、局灶性核周腔扩张、异染色质减少、胞质内细胞器肿胀、核糖体减少 ;某些胶质细胞亦见类似改变 ;神经毡膜性结构不完整。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 .母体叶酸缺乏能造成胎鼠皮层脑组织超微结构的改变 ,可能导致神经元功能的紊乱和丧失 ,以致防碍脑结构和脑功能的正?

CHANGES OF BLOOD CELLS AND ULTRASTRUCTURE IN FETAL RATS WITH MATERNAL FOLATE DEFICIENCY

To verify the effect of folate deficiency on fetal rats′ intrauterine brain development, the change ultrastructure in fetal rats′ brain with maternal folate deficiency was studied, our research was expected to provide some evidence on the aspect of cellular ultrastructure. Female Sprague-Dawley rats, 30 in the folate deficient group and 20 in the control group, received a pruified diet without or with folate 2 mg 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 the ultrastructrue of lobus frontalis was observed by transmission electronmicroscopy. Results showed: 1. Dams in deficient group bad significant lower serum folate concentration before mating or at the end of gestation than those in control group. Hypersegmented neutrophils were present in deficient group. Fetal serum folate concentration in this group was lower than those in control group too and was associated with macrocyte and. 2. The ultrastructrue of lobus frontalis was changed such as: (1)the large nuclear indetations; the distension of part of perinuclear space; the reduction of heterochromatine and ribosome content of the cytolasm; the swollen cytoplasmic organelles in neuron. (2)similar changes were found in some gliocyte. (3)neuropil was swollen and partially damaged. Conclusion: 1. Giving female SD rats folate-free diet form. 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. Maternal folate deficiency could change the ultrastructure of fetal rat′s lobus frontalis. It maybe lead to abnormality of neuronal function and would disturb fetal brain developmen. 3. Folate supplement during periconception should be prolonged to delivery.