College of Eco-Environmental Engineering, Qinghai University, Xining, Qinghai, China.
State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, Qinghai, China.
PeerJ. 2024 Oct 1;12:e18250. doi: 10.7717/peerj.18250. eCollection 2024.
Collagen is crucial for tissue structure, functional maintenance, and cellular processes such as proliferation and differentiation. However, the specific changes in collagen expression and its associated genes in the lung tissues of yaks at high altitudes and their relationship with environmental adaptation remain poorly understood. Studying differences in the content of collagen fibers and gene expression between yaks at high (4,500 m) and low (2,600 m) altitudes, as well as between cattle at low altitudes (2,600 m). Using Masson staining, we found that the collagen fiber content in the lung tissues of yaks at low altitude was significantly higher compared to yaks at high altitude and cattle at the same altitude ( < 0.05). It was revealed through transcriptomic analyses that genes differentially expressed between high and low altitude yaks, as well as between low altitude yaks and cattle, were notably enriched in pathways related to cell adhesion, collagen synthesis, focal adhesion, and ECM-receptor interactions. Specifically, genes involved in mesenchymal collagen synthesis (., , , ), basement membrane collagen synthesis (., , , , ), and peripheral collagen synthesis (., , , , ) were significantly upregulated in the lung tissues of yaks at low altitude compared to their high altitude counterparts and cattle ( < 0.05). In conclusion, yaks at lower altitudes exhibit increased collagen synthesis by upregulating collagen gene expression, which contributes to maintaining alveolar stability and septal flexibility. Conversely, the expression of collagen genes in yak lung tissues was down-regulated with the increase in altitude, and it was speculated that the decrease in collagen may be used to constrain the function of elastic fibers that are more abundant at high altitude, so as to enable them to adapt to the harsh environment with hypoxia and high altitude. This adaptation mechanism highlights the role of collagen in environmental acclimatization and contributes to our understanding of how altitude and species influence collagen-related physiological processes in yaks.
胶原蛋白对于组织结构、功能维持以及细胞增殖和分化等过程至关重要。然而，高海拔牦牛肺组织中胶原蛋白表达及其相关基因的具体变化及其与环境适应的关系尚不清楚。本研究通过比较高海拔（4500 米）和低海拔（2600 米）牦牛以及低海拔（2600 米）牛之间的胶原纤维含量和基因表达差异，研究了胶原纤维含量和基因表达的差异。采用 Masson 染色法，发现低海拔牦牛肺组织中胶原纤维含量明显高于高海拔牦牛和同海拔牛（<0.05）。通过转录组分析发现，高海拔和低海拔牦牛之间以及低海拔牦牛和牛之间差异表达的基因，在细胞黏附、胶原蛋白合成、焦点黏附、细胞外基质-受体相互作用等途径中显著富集。具体来说，与间质胶原蛋白合成（.,,, ）、基底膜胶原蛋白合成（.,,,, ）和外周胶原蛋白合成（.,,,, ）相关的基因在低海拔牦牛肺组织中显著上调（<0.05）。综上所述，低海拔牦牛通过上调胶原蛋白基因表达来增加胶原蛋白合成，从而有助于维持肺泡稳定性和隔室灵活性。相反，随着海拔的升高，牦牛肺组织中胶原蛋白基因的表达下调，推测胶原蛋白的减少可能是为了限制高海拔时更为丰富的弹性纤维的功能，从而使它们能够适应缺氧和高海拔的恶劣环境。这种适应机制强调了胶原蛋白在环境适应中的作用，并有助于我们理解海拔和物种如何影响牦牛中与胶原蛋白相关的生理过程。
