叶酸缺乏对孕鼠子代心脏超微结构及心脏发育相关基因表达的影响

Influence of Folic Acid Deficiency during Pregnancy on Offspring Cardiac Ultrastructure and Expressions of Heart Development-Related Genes in Mice

目的探讨叶酸缺乏孕鼠的子代心脏发育过程中GATA-4、NKx2.5基因表达和超微结构的改变。方法成熟雌性SD大鼠36只随机分为实验组和对照组,分别喂以缺乏叶酸和含叶酸饲料2周后与成熟SD雄性大鼠交配,分别取孕13.5d(E13.5d)、孕17.5d(E17.5d)胚胎及新生鼠心脏。用实时扩增聚合酶链反应(RT-PCR)检测胚胎及新生鼠心脏GATA-4、NKx2.5基因3个时期的表达。电镜观察新生鼠心脏的超微结构。结果1.经切片观察E13.5d胚胎实验组发现明显发育延迟占35.14%,E17.5d胚胎实验组发现明显心脏畸形占43.24%,新生鼠实验组发现明显心脏畸形占69.44%。2.GATA-4、NKx2.5基因在3个时期相对表达量实验组低于对照组(Pa<0.05)。3.实验组新生鼠心脏电镜下肌细胞胞浆内膜性结构退行性变、肌丝明暗带(z带)不清、线粒体内基质凝结、肌浆网扩张;对照组正常或破坏很轻。结论孕鼠叶酸的缺乏影响子代心脏GATA-4、NKx2.5基因水平的表达,并导致心脏超微结构和大体结构的改变,从而造成心脏发育缺陷。

Objective To explore the expressions of GATA - 4, NKx2.5 and the change of offspring cardiac ultrastructure during development of embryo, whose mother is deficient of folic acid. Methods Control group and study group were chosen from the total 36 adult female SD rats randomly copulated with the male normal rats after feeding folic acid involved and not - inolved fodder for 2 weeks. Heart of the 13.5 days, 17.5 days embryos and the newborns were cut. The ultrastuetural characters of newborn＇s cardiac myocardium at the three period were observed, The expressions of GATA -4 , NKx2.5mRNA of embryo＇s heart at the three period were detected by real time - polymerase chain reaction（ RT - PCR）, Results 1, The histologic study showed that in the study group ,35.14% of 13.5 dembryos appeared obviously delayed in the heart development,43, 24% of 17.5 d embryos appeard heart malformation,69.44% of the newborns appeared obviously delayed in the heart development. 2. At the three period, the expressions of GATA - 4 and NKx2.5 of the study group were weaker than those of control group （Pa 〈0. 05）. 3, In control group,the muscle fibers showed an oriented arrangement and mitochondria were well distributed beneath the sarcolemma or in the field of myofibrils, z - bands were equal and clear. In study group, the sarcolemma often showed pouches filled with abnormal mitochondria and the muscle fibers showed a disoriented arrangement. In addition, the myofibrils showed hypercontraction, even lost normal structure, and the z - bands were thickened. Conclusion The changes of expressions of GATA - 4 and NKx2.5 and the cardiac ultrastructure maybe resulted from folic acid deficiency during pregnancy.