ANDZIAK, B.A.*; BUFFENSTEIN, R.; O’CONNOR, T.P.: Does antioxidant enzyme activity explain the extended longevity of naked mole-rats?

Aging decreases organismal performance by impairing normal physiological function. Although the proximate mechanisms remain to be elucidated, many of the deleterious effects of aging are attributed to accumulation of molecular oxidative damage. Lifetime accrual of damage is due to the net difference between the generation of Reactive Oxygen Species (ROS) and their removal by antioxidants. Thus, interspecies differences in longevity may be due to disparate antioxidant capacities. We tested this hypothesis in naked mole-rats (Heterocephalus glaber). These mouse-sized (35g) rodents live more than 26 years in captivity, exceeding allometric predictions for maximal lifespan by approximately seven-fold. We questioned whether the impressive longevity of naked mole-rats was due to superior antioxidant activities. Liver Cu/Zn superoxide dismutase (SOD) activity in young and old naked mole-rats were compared with that of much shorter-lived mice using commercial colorimetric assays (Oxis, Portland, Or). Similar levels of SOD activity in both young mole-rats and mice were detected, suggesting that prolonged longevity of naked mole-rats is not due to enhanced anti-oxidant activity. Furthermore, a moderate decline in SOD with age was evident in mole-rats. Our preliminary findings concur with previously published aging studies. The impressive longevity of naked mole-rats is apparently not due to superior SOD activities, but rather may be due to lower rates of ROS generation.