How carpet sharks avoid brain damage from oxygen deprivation

Embargoed until: Publicly released: 2023-10-11 10:01

Australia; New Zealand

Image by Jim Capaldi via Wikimedia Commons

Two species of carpet shark have evolved unique strategies to prevent brain damage during episodes of oxygen deprivation and reoxygenation, according to New Zealand and Australian researchers. The grey carpet shark responds by producing more red blood cells to supply metabolically active organs with extra oxygen, while the epaulette shark reduces the production of damaging high-energy molecules in its brain mitochondria by suppressing its metabolism. While the epaulette shark was more tolerant of oxygen deprivation, researchers say that both strategies may help researchers design interventions to mitigate brain damage from oxidative stress in other species.

Media release

From: The Royal Society

Succinate-mediated ROS production in the anoxia-tolerant epaulette (Hemiscyllium ocellatum) and grey carpet (Chiloscyllium punctatum) sharks

Anoxia and re-oxygenation, a common occurrence in certain shark habitats, can lead to brain damage due to oxidative stress. However, two closely related shark species, the epaulette shark and the grey carpet shark, have adapted to endure this stress without significant brain injury. They employ different survival strategies, with the epaulette shark being able to suppress metabolism and its mitochondria having a unique ability to limit succinate oxidation after the stress. Our team found that despite similar mitochondrial respiration, the epaulette shark produced only half as many harmful reactive oxygen species (ROS) as the grey carpet shark. This sheds light on strategies to reduce brain injury during such stress.

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Research The Royal Society, Web page

Journal/
conference: Biology Letters

Research:Paper

Organisation/s: University of Auckland, Griffith University

Funder: This research was funded personally by GMCR. A.J.R.H. and J.B.L.D. were supported by the Marsden funds of The Royal Society of New Zealand (grant no. 14-UOA-210).

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