Hypoxia- and hyperoxia-related gene expression dynamics during developmental critical windows of the tropical gar Atractosteus tropicus

• Published in: Comparative biochemistry and physiology. Part A, Molecular & integrative physiology Vol. 263; p. 111093
• Main Authors: Martínez-Bautista, Gil, Martínez-Burguete, Talhia, Peña-Marín, Emyr Saul, Jiménez-Martínez, Luis Daniel, Martínez-García, Rafael, Camarillo-Coop, Susana, Burggren, Warren W., Álvarez-González, Carlos Alfonso
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.2022
• Subjects: Animals; Aquaculture; Critical windows; Development; Erythropoietin - genetics; Female; Fish Diseases - genetics; Fish Diseases - physiopathology; Fish Proteins - genetics; Fishes - genetics; Fishes - growth & development; Fishes - physiology; Gene expression; Gene Expression Regulation, Developmental; Hif-1α; Hyperoxia; Hyperoxia - genetics; Hyperoxia - physiopathology; Hyperoxia - veterinary; Hypoxia; Hypoxia - genetics; Hypoxia - physiopathology; Hypoxia - veterinary; Hypoxia-Inducible Factor 1, alpha Subunit - antagonists & inhibitors; Hypoxia-Inducible Factor 1, alpha Subunit - genetics; Interleukin-8 - genetics; Male; Receptors, Glucocorticoid - genetics; Respiratory Physiological Phenomena; Sodium-Hydrogen Exchanger 1 - genetics; Tropical gar; Hyperoxia; Development; Hypoxia; Tropical gar; Hif-1α; Critical windows; Gene expression
• ISSN: 1095-6433; 1531-4332
• DOI: 10.1016/j.cbpa.2021.111093

Aquatic hypoxia is both a naturally-occurring and anthropogenically-generated event. Fish species have evolved different adaptations to cope with hypoxic environments, including gill modifications and air breathing. However, little is known about the molecular mechanisms involved in the respiration of embryonic and larval fishes during critical windows of development. We assessed expression of the genes hif-1α, fih-1, nhe1, epo, gr and il8 using the developing tropical gar as a piscine model during three developmental periods (fertilization to hatch, 1 to 6 days post hatch (dph) and 7 to 12 dph) when exposed to normoxia (~7.43 mg/L DO), hypoxia (~2.5 mg/L DO) or hyperoxia (~9.15 mg/L DO). All genes had higher expression when fish were exposed to either hypoxia or hyperoxia during the first two developmental periods. However, fish continuously exposed to hypoxia had increased expression of the six genes by hatching and 6 dph, and by 12 dph only hif-1α still had increased expression. The middle developmental period was the most hypoxia-sensitive, coinciding with several changes in physiology and morphology. The oldest larvae were the most resilient to gene expression change, with little variation in expression of the six genes compared. This study is the first to relate the molecular response of an air-breathing fish to oxygen availability to developmental critical windows and contributes to our understanding of some molecular responses of developing fish to changes in oxygen availability. [Display omitted] •Regulation of genes varies with time of exposure, type of stressor and developmental time.•Period from fertilization to 6 dph results in higher expression of genes in response to hypoxia/hyperoxia.•Period from 7 to 12 dph resulted as the most resilient with little variation in gene expression.