Machida N, Yasuda J, Too K, Kudo N
Veterinary Hospital, Department of Veterinary Anatomy, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
Equine Vet J. 1988 Jul;20(4):249-54. doi: 10.1111/j.2042-3306.1988.tb01516.x.
The obliteration processes of the ductus arteriosus of equine foetuses and newborn foals were studied morphometrically and histologically. The length, internal and external diameters and circumference of the ductus in equine foetuses increased progressively and linearly up to 310 days with advancing foetal age, but the values, especially the internal diameter, decreased from 320 to 330 days. After birth, the ductal measurements decreased gradually and ductal closure was found in three of 14 foals examined on the first day post partum, in two of six on the second day and in nine of nine on the third day or later, suggesting that the ductus arteriosus closes physiologically within three days after birth. Microscopical findings of the ductus arteriosus were characterised by the rearrangement of smooth muscle cells in the inner media and intimal thickening in foetuses, and by the central displacement of the intima in newborn foals. It was concluded that the ductus arteriosus begins to undergo preparatory modifications during intrauterine life, when the vessel is still functional, and that the most significant starting point of change in the obliteration processes is the rearrangement of smooth muscle cells in the inner media, which occurs during pre- and post natal life.
对马胎儿和新生马驹动脉导管的闭塞过程进行了形态计量学和组织学研究。随着胎龄增加，马胎儿动脉导管的长度、内径、外径和周长在310天前逐渐呈线性增加，但在320至330天这些数值，尤其是内径有所下降。出生后，导管测量值逐渐减小，在产后第一天检查的14匹小马驹中有3匹发现导管闭合，第二天检查的6匹中有2匹，第三天及以后检查的9匹中有9匹，这表明动脉导管在出生后三天内生理性闭合。动脉导管的显微镜检查结果显示，胎儿期其特征为中膜内层平滑肌细胞重排和内膜增厚，新生马驹期则为内膜向中央移位。得出的结论是，动脉导管在子宫内生活期间，当该血管仍有功能时就开始进行准备性改变，闭塞过程中最显著的变化起始点是中膜内层平滑肌细胞的重排，这发生在出生前和出生后。
