Allen K M, Haworth S G
J Pathol. 1986 Nov;150(3):205-12. doi: 10.1002/path.1711500309.
Twelve Large White pigs aged less than 1 min, and 3, 5.5, and 14 days were exposed to hypoxia (380 torr) for 2.5-3 days. The wall structure of terminal bronchiolar (resistance arteries) and elastic arteries was assessed by light and electron microscopy using quantitative morphometric techniques. In animals exposed from birth, mean terminal bronchiolar arterial medial thickness was increased (p less than 0.05) because endothelial and smooth muscle cells (SMCs) retained their fetal shape, position, overlap, interdigitation and the low surface/volume ratio characteristic of fetal life. In all older animals, the cells had a normal postnatal shape and surface/volume ratio. In the elastic vessels hypoxia did not prevent the normal postnatal reduction in mean SMC diameter of animals exposed from birth. SMC hypertrophy did not occur in any age group, but all animals save those first exposed at 14 days, showed an increase in SMC myofilament volume density (p less than 0.01). Connective tissue volume density also increased (p less than 0.01), mainly due to an increase in elastin and ground substance. Thus a short period of neonatal hypoxia impaired adaptation and appeared to potentiate contractile capacity in stiff-walled arteries but elicited a less marked response from animals first exposed at 14 days.
选取12头年龄小于1分钟、3天、5.5天和14天的大白猪，使其暴露于低氧环境（380托）中2.5 - 3天。采用定量形态计量学技术，通过光学显微镜和电子显微镜评估终末细支气管（阻力动脉）和弹性动脉的壁结构。在出生时即暴露于低氧环境的动物中，终末细支气管动脉的平均中膜厚度增加（p < 0.05），因为内皮细胞和平滑肌细胞保留了其胎儿时期的形状、位置、重叠、指状交叉以及胎儿期特有的低表面积/体积比。在所有年龄较大的动物中，细胞具有正常的出生后形状和表面积/体积比。在弹性血管中，低氧并未阻止出生时即暴露于低氧环境的动物出生后平均平滑肌细胞直径的正常减小。平滑肌细胞肥大在任何年龄组均未发生，但除了在14天时首次暴露的动物外，所有动物的平滑肌细胞肌丝体积密度均增加（p < 0.01）。结缔组织体积密度也增加（p < 0.01），主要是由于弹性蛋白和基质的增加。因此，新生儿期短时间的低氧会损害适应性，并似乎增强了硬壁动脉的收缩能力，但对在14天时首次暴露的动物引起的反应不太明显。
