Segmentation features and structural organization of the intrapulmonary artery of the yak

Abstract

This study aims to systematically investigate intrapulmonary artery segmentation, blood vessel wall characteristics and structure organization, and the interrelation between intrapulmonary artery structure and plateau hypoxia adaptation in yak. The normal intrapulmonary artery structure of the yak had been studied using histological methods and transmission electron microscopy. The intrapulmonary artery of the yak was also examined using morphometric analysis and angiography. Results showed that the elastic intrapulmonary artery is divided into two types, namely, classical and transitional elastic segments. The muscular intrapulmonary artery is divided into three types, namely, transitional, classical muscular, and muscular arteriole segments. In the transitional elastic artery, elastic fibers and smooth muscles are linked through three models of ends, lateral branches, and branch tops. Two phenomena are possible for the transition from the elastic intrapulmonary artery to the muscular artery. One phenomenon postulates that a less elastic membrane is first increased and then suddenly decreased, and another supposes that the elastic membrane is gradually reduced and assembled in one to two layers before entering the transitional muscular artery. The smooth muscle of the intrapulmonary artery tunica media had more apophysis; it was physically connected with elastic membrane or fiber and composed of functionally resilient unit of the intrapulmonary arterial wall. Glycogenosomes increased in the muscular intrapulmonary artery smooth muscle cells. It exist one to two layers intact smooth muscle in intrapulmonary arteriole, the presence of intact smooth muscle in the intrapulmonary arteriole of the yak is a kind of structure adaptation to low-oxygen environment.

Changes in the Anatomic and Microscopic Structure and the Expression of HIF-1α and VEGF of the Yak Heart with Aging and Hypoxia

“…Heath et al has proved that there is no Pulmonary hypertension in yak [ 25 ]. Zhou et al reported that there were infact smooth muscle cells presented in the intrapulmonary arteriole of lung in yak, and the low oxygen environment can cause the thickening of the tunicae media of pulmonary artery of yak [ 26 ]. Researchers also found that the pulmonary artery of adult yak had more elastic fibers than that of adult cattle, which could maintain good retraction force of the pulmonary artery and ejecting blood [ 27 ].…”

Differences in proteomic profiles between yak and three cattle strains provide insights into molecular mechanisms underlying high‐altitude adaptation

“…The heart and lungs are important organs involved in the adaptation to low temperature and hypoxic environments. Previous studies highlighted these organs in yaks due to their special morphological and physiological characteristics contributing to their adaptation to high‐altitude environments (Duan et al, 2012; Zhou et al, 2013). Compared to low‐altitude cattle, the lung of yak displays shorter and thicker trachea, and more alveoli and capillaries per unit area (Chen et al, 2006; Yang et al, 2010).…”

Age-related differences in hypoxia-associated genes and cytokine profile in male Wistar rats

“…The myocardium level of HIF-1α was higher in 2-year old yaks, than in younger and older ones. However, the myocardium HIF-dependent VEGF level increased throughout the animals' life and the oldest yaks demonstrated the highest levels (Duan et al, 2012;Zhou et al, 2013;He et al, 2016).…”