To clarify the effects of acute hypoxia on physiological response and mRNA expression of Hypoxia-inducible factors (HIFs) in Siberian sturgeon, a chondrostean fish, severe hypoxia treatment was implemented by transfer of sturgeons from normoxia (DO =7 mg/mL) to hypoxia (DO = 2 mg/mL). We found that the levels of serum cortisol, GLU, SOD, LDH, CK and CREA increased significantly at the early time-points post hypoxia exposure. Whereas the activity of immune related enzyme — AKP showed a sudden drop, followed by a recovery. Further, we identified and characterized three hif-αs cDNA sequences, namely Abhif-1α, Abhif-2α, and Abhif-3α. The mRNA abundance of three hif-αs was all rich in brain, heart and liver. During acute hypoxia exposure, Abhif-1α and Abhif-3α mRNA expression levels increased significantly in the heart, gill and brain at early time-points, and gradually declined later on. Abhif-2α only showed a slight increase in the gill upon hypoxia stress. In conclusion, we observed that, acute hypoxia affected the muscle function and immune related enzyme activity of Acipenser baeri; in response to hypoxia stress, sturgeons enhanced antioxidant capacity, anaerobic metabolism and up regulated the transcriptional expression of Abhif-1α and Abhif-3α. Our results might be helpful for further understanding of the potential effect of hypoxia on chondrostean fish and their molecular anti-hypoxia mechanisms.

为了阐明急性缺氧对西伯利亚鲟（一种软骨鱼）生理反应和缺氧诱导因子（HIFs）mRNA表达的影响，通过将鲟鱼从常氧（DO = 7 mg / mL）转移到缺氧来实施严重缺氧处理(DO = 2 毫克/毫升)。我们发现血清皮质醇、GLU、SOD、LDH、CK 和 CREA 的水平在缺氧暴露后的早期时间点显着增加。而免疫相关酶——AKP的活性则表现为突然下降，随后又恢复。此外，我们鉴定并表征了三个hif-αs cDNA 序列，即Abhif-1α、Abhif-2α和Abhif-3α。三个hif-αs的mRNA丰度都富含大脑、心脏和肝脏。在急性缺氧暴露期间，Abhif-1α和Abhif-3α mRNA 表达水平在早期时间点在心脏、鳃和大脑中显着增加，然后逐渐下降。Abhif-2α仅在缺氧应激下显示鳃略有增加。综上所述，我们观察到急性缺氧会影响Acipenser baeri的肌肉功能和免疫相关酶活性；响应缺氧应激，鲟鱼增强抗氧化能力、厌氧代谢并上调Abhif-1α和Abhif-3α的转录表达. 我们的研究结果可能有助于进一步了解缺氧对软骨鱼的潜在影响及其分子抗缺氧机制。