Brook F A, Estibeiro J P, Copp A J
Department of Zoology, University of Oxford, UK.
J Med Genet. 1994 May;31(5):383-7. doi: 10.1136/jmg.31.5.383.
The susceptibility of females to anencephaly is well established and has been suggested to result from a slower rate of growth and development of female embryos during cranial neurulation. We have tested this hypothesis by measuring the rates of growth and development, both in utero and in vitro, of male and female embryos of the curly tail (ct) mutant mouse strain, in which cranial neural tube defects occur primarily in females. Embryonic growth was assessed by increase in protein content, while development progression was judged from increase in somite number and morphological score. Embryos were sexed by use of the polymerase chain reaction to amplify a DNA sequence specific to the Y chromosome, and by sex chromatin analysis. We find that, during neurulation (between 8.5 and 10.5 days of gestation), males are advanced in growth and development relative to their female litter mates, but that the rates of growth and development do not differ between the sexes during this period. We conclude that rate of embryonic growth and development is unlikely to determine susceptibility to cranial neural tube defects. It seems more likely that male and female embryos differ in some specific aspect(s) of the neurulation process that increases the susceptibility of females to development of anencephaly.
女性对无脑儿的易感性已得到充分证实，有人认为这是由于女性胚胎在颅神经形成过程中生长发育速度较慢所致。我们通过测量卷尾（ct）突变小鼠品系的雄性和雌性胚胎在子宫内和体外的生长发育速度，对这一假设进行了验证。在该品系中，颅神经管缺陷主要发生在雌性胚胎中。通过蛋白质含量的增加来评估胚胎生长，而根据体节数量的增加和形态学评分来判断发育进程。利用聚合酶链反应扩增Y染色体特异性DNA序列，并通过性染色质分析对胚胎进行性别鉴定。我们发现，在神经形成期间（妊娠8.5至10.5天之间），相对于雌性同窝仔，雄性在生长发育上更为超前，但在此期间两性的生长发育速度并无差异。我们得出结论，胚胎生长发育速度不太可能决定对颅神经管缺陷的易感性。更有可能的是，雄性和雌性胚胎在神经形成过程的某些特定方面存在差异，这增加了雌性发生无脑儿的易感性。
