Exposure to Intermittent Environmental Hypoxia Promotes Vascular Remodeling through Angiogenesis in the Liver of Largemouth Bass (Micropterus salmoides).

Abstract

In this study, we explored the effects of 4 weeks of intermittent hypoxic exposure (IHE) on liver angiogenesis and related regulatory mechanisms in largemouth bass (Micropterus salmoides). The results indicated that the O2 tension for loss of equilibrium (LOE) decreased from 1.17 to 0.66 mg/L after 4 weeks of IHE. Meanwhile, the red blood cell (RBC) and hemoglobin concentrations significantly increased during IHE. Our investigation also found that the observed increase in angiogenesis was correlated with a high expression of related regulators, such as Jagged, phosphoinositide-3-kinase (PI3K), and mitogen-activated protein kinase (MAPK). After 4 weeks of IHE, the overexpression of factors related to angiogenesis processes mediated by HIF-independent pathways (such as nuclear factor kappa-B (NF-κB), NADPH oxidase 1 (NOX1), and interleukin 8 (IL8)) was correlated with the accumulation of lactic acid (LA) in the liver. The addition of cabozantinib, a specific inhibitor of VEGFR2, blocked the phosphorylation of VEGFR2 and downregulated the expression of downstream angiogenesis regulators in largemouth bass hepatocytes exposed to hypoxia for 4 h. These results suggested that IHE promoted liver vascular remodeling by the regulation of angiogenesis factors, presenting a potential mechanism for the improvement of hypoxia tolerance in largemouth bass.

• Authors: Haoxiao Yan, Liulan Zhao, Qishuang He, Yifan Hu, Quanxi Li, Kuo He, Dongmei Zhang, Qiao Liu, Jie Luo, Wei Luo, Shiyi Chen, Lisen Li, Song Yang
• Journal: Environmental science & technology (Environ Sci Technol) Vol. 57 Issue 46 Pg. 17796-17807 (Nov 21 2023) ISSN: 1520-5851 [Electronic] United States
• PMID: 36802614 (Publication Type: Journal Article)

Topics

• Animals
• Bass (metabolism)
• Vascular Remodeling
• Angiogenesis
• Hypoxia (metabolism)
• Liver (metabolism)