成年牦牛与黄牛肺内肺动脉结构组织和形态学比较分析

Comparative structural organization and morphological analyses of intrapulmonary artery of adult yak and cattle

运用组织学研究方法,比较成年牦牛和平原黄牛肺动脉的结构组织和形态学差异,初步探讨成年牦牛肺动脉对低氧的适应性结构。结果表明,成年牦牛肺动脉管壁直径小于200μm时,仍含有较多的弹性纤维,在直径为50μm的肺动脉管壁中,仍存在1-2层完整的平滑肌。而成年黄牛其肺动脉管壁直径小于100μm时,其管壁中含有的弹性纤维比成年牦牛直径大小相似的肺动脉管壁中的弹性纤维少,平滑肌消失或呈月牙状分布,但外弹性膜完整。成年平原黄牛肺动脉血管中膜的MT值随管径的增加逐渐减小,成年牦牛肺动脉血管中膜MT值在管径为100-200μm时最大,然后逐渐减小。至肺门部时,其肺动脉血管中膜MT值接近相等,且差异不显著。因此,成年牦牛肺动脉含有的弹性纤维比成年平原黄牛多,该结构特点是成年牦牛在高原低氧环境下维持肺动脉较好射血功能的结构基础,此外,与成年黄牛比较可见,成年牦牛50μm直径的肺微动脉仍具有完整的平滑肌层,这一现象可能是牦牛在高原低氧环境下维持较好血流的结构基础。

The study aimed at comparisson of the structural organization and morphological differences in pulmonary artery between adult yak and plain cattle By using histologic study method,preliminarily discuss the structural adaptation to hypoxia of the pulmonary artery in yak.Results show that the pulmonary arterial less than 200μm diameter wall had more elastic fibers,and one to two layers of intact smooth muscles（SM）in 50μm diameter.Elastic fibers in the pulmonary arterial wall of plain cattle were less than those of adult yak when the pulmonary artery diameter was below 100μm,SM was missing,or as a crescent shape distribution.However,the external elastic membrane was complete.The medial muscle thickness（MT）numerical value peaked when the diameter of the pulmonary artery of adult cattle was less than 50μm,and decreased with increasing diameter.The MT numerical value of the pulmonary artery of adult yak peaked between100 and 200μm,and gradually decreased.The MT numerical value was almost equal at the hilum of lung,the difference was insignificant.Thus,the pulmonary artery of adult yak had more elastic fibers than that of adult cattle.The pulmonary artery of adult yak had a structural foundation for maintaining good retraction force of the pulmonary artery and ejecting blood.Moreover,the SM of the arteriole wall of yak was more intact than that of adult cattle;this phenomenon may be a structural foundation for maintaining good blood flow of pulmonary arteriole under low oxygen conditions.