The Evolution and Ecology of Oxidative and Antioxidant Status: A Comparative Approach in African Mole-Rats

Abstract

The naked mole-rat of the family Bathyergidae has been the showpiece for ageing research as they contradict the traditional understanding of the oxidative stress theory of ageing. Some other bathyergids also possess increased lifespans, but there has been a remarkable lack of comparison between species within the family Bathyergidae. This study set out to investigate how plasma oxidative markers (total oxidant status (TOS), total antioxidant capacity (TAC), and the oxidative stress index (OSI)) differ between five species and three subspecies of bathyergids, differing in their maximum lifespan potential (MLSP), resting metabolic rate, aridity index (AI), and sociality. We also investigated how oxidative markers may differ between captive and wild-caught mole-rats. Our results reveal that increased TOS, TAC, and OSI are associated with increased MLSP. This pattern is more prevalent in the social-living species than the solitary-living species. We also found that oxidative variables decreased with an increasing AI and that wild-caught individuals typically have higher antioxidants. We speculate that the correlation between higher oxidative markers and MLSP is due to the hypoxia-tolerance of the mole-rats investigated. Hormesis (the biphasic response to oxidative stress promoting protection) is a likely mechanism behind the increased oxidative markers observed and promotes longevity in some members of the Bathyergidae family.

Relationship between Hypoxia and Hypercapnia Tolerance and Life Expectancy

“…Similarly, mice exposed to a hypercapnic–hypoxic environment show a significant decrease in body temperature and metabolic rate [ 34 , 35 ]. Moreover, some researchers suggest that there is a correlation between high resistance to oxidative stress and hypoxia resistance in naked mole rats [ 36 ].…”

“…Such data serve as important evidence for the potential role of the hypercapnic component in the mechanism of defense against aging, which is largely due to oxidative stress and free radical reactions [ 63 , 64 ]. It should be noted that in the naked mole rats (resistant to hypoxia and hypercapnia), an effective antioxidant status is also considered by a number of researchers to be a likely mechanism for the observed longevity [ 36 , 65 ].…”

Redox Metabolism in Ecophysiology and Evolution

“…Jacobs et al [ 10 ] explored several factors that could be associated with redox balance and oxidative stress, such as phylogeny, social behavior, captivity, environmental aridity, resting metabolic rate (RMR), and maximum lifespan potential (MLSP).…”