Is Anoxia Tolerance a Common Trait in Fish Cell Lines?

Most vertebrates need a constant supply of oxygen to sustain life, with disruption to O2 supply or delivery quickly leading to cell and tissue damage and death. Many aquatic species are able to withstand long periods without O2 due to evolving to survive the regular periods of hypoxia and anoxia in their natural habitat. The Austrofundulus limnaeus, or the annual killifish, in particular have shown the highest anoxia tolerance in all vertebrates and is a promising model for developing effective treatments for anoxia-related damage, such as heart attacks and strokes. The A. limnaeus are not the only fish with anoxia tolerance, as many other fish have evolved to survive similarly harsh environments. We aimed to determine if other fish have similar anoxia tolerance by comparing the cell lines of LtE from the California grunion (Leuresthes tenuis), OmB from the Mozambique tilapia (Oreochromis mossambicus), ZEM2S from the zebrafish (Danio rerio), and WS40NE from the annual killifish (Austrofundulus limnaeus). Cells from the LtE, OmB, and ZEM2S cell lines were found to not have as high of anoxia tolerance compared to WS40NE, but were found to have significantly higher tolerance than mammalian cells, surviving 11 days of anoxia compared to 3 days in other mammalian cells. This suggests that A. limnaeus has unique abilities beyond other fishes in terms of their anoxia tolerance.