Background: Yaks inhabit high-altitude are well-adapted to the hypoxic environments. Though, the mechanisms involved in regulatory myocardial protein expression at high-altitude were not completely understood.

Objective: To revel the molecular mechanism of hypoxic adaptation in yak, here we have applied comparative myocardial proteomics in between yak and cattle by isobaric Tag for Relative and Absolute Quantitation (iTRAQ) labelling.

Methods: To understand the systematic protein expression variations in myocardial tissues that explain the hypoxic adaptation in yak, we have performed iTRAQ analysis combined with Liquid Chromatography- Tandem Mass Spectrometry (LC-MS/MS). Bioinformatics analysis was performed to find the association of these Differentially Expressed Proteins (DEPs) in different functions and pathways. Protein to protein interaction was analyzed by using STRING database.

Results: 686 Differentially Expressed Proteins (DEPs) were identified in yak with respect to cattle. From which, 480 DEPs were up-regulated and 206 were down-regulated in yak. Upregulated expression of ASB4, STAT, HRG, RHO and TSP4 in yak may be associated with angiogenesis, cardiovascular development, response to pressure overload to heart and regulation of myocardial contraction in response to increased oxygen tension. The up-regulation of mitochondrial proteins, ACAD8, GPDH-M, PTPMT1, and ALDH2, may have contributed to oxidation within mitochondria, hypoxia-induced cell metabolism and protection of heart against cardiac ischemic injuries. Further, the upregulated expression of SAA1, PTX, HP and MBL2 involved in immune response potentially helpful in myocardial protection against ischemic injuries, extracellular matrix remodeling and free heme neutralization/ clearance in oxygen-deficient environment.

Conclusion: Therefore, the identification of these myocardial proteins in will be conducive to investigation of the molecular mechanisms involved in hypoxic adaptations of yaks at high-altitude condition.

背景：Ya牛居住在高海拔地区，非常适合低氧环境。但是，高海拔调节心肌蛋白表达的机制尚不完全清楚。

目的：为揭示vel牛低氧适应的分子机制，在这里我们通过等压相对绝对定量（iTRAQ）标记在comparative牛和牛之间应用了比较的心肌蛋白质组学。

方法：为了了解解释tissue牛缺氧适应性的心肌组织中系统性蛋白表达变化，我们进行了iTRAQ分析与液相色谱-串联质谱（LC-MS / MS）结合。进行了生物信息学分析，以发现这些差异表达蛋白（DEP）在不同功能和途径中的关联。通过使用STRING数据库分析了蛋白质之间的相互作用。

结果：牛中鉴定出686种与牛有关的差异表达蛋白（DEP）。由此，牛中上调了480个DEP，下调了206个DEP。SB牛中ASB4，STAT，HRG，RHO和TSP4的表达上调可能与血管生成，心血管发育，对心脏压力超负荷的反应以及对氧张力升高的心肌收缩的调节有关。线粒体蛋白，ACAD8，GPDH-M，PTPMT1和ALDH2的上调可能促进了线粒体内的氧化，缺氧诱导的细胞代谢以及保护心脏免受心脏缺血性损伤。此外，参与免疫反应的SAA1，PTX，HP和MBL2的表达上调可能有助于保护心肌免受缺血性损伤，

结论：因此，这些心肌蛋白的鉴定将有助于研究in牛在高海拔条件下低氧适应的分子机制。