关键词: 氧化应激, 冬眠, 蜥蜴, 代谢, 环境

Abstract: Studies of oxidative stress contribute to understanding relationships between animal life history and habitat. Oxidative stress in animals is closely related to their metabolism. To explore the effects of habitat and hibernation on oxidative and metabolic responses in lizards, we compared the basal activities of key antioxidant enzymes and metabolic enzymes and liver glycogen content in Eremias multiocellata from a low-altitude desert with those in Scincella tsinlingensis from a high-altitude mountainous region. We assessed these parameters and the expression of the genes encoding glycogen synthase-2 (GYS2), phosphorylase (PYGL) and xanthine dehydrogenase (XDH) in E. multiocellata during summer active period (July), hibernating period (December), and spring arousal period (April). The activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase (CAT), and citrate synthase (CS) were significantly lower in E. multiocellata than in S. tsinlingensis, while malondialdehyde (MDA) displayed an opposite trend. There were no significant differences in liver glycogen content between the two species. Liver SOD, GPX, and CAT activities in E. multiocellata were significantly higher during arousal period than those during active and hibernating periods, while MDA content was significantly lower in hibernating and arousal periods than that in the active period. CS activity was significantly higher during hibernation than that during the other periods. Liver glycogen was significantly reduced during arousal period relative to active and hibernating periods. Expression of GYS2, PYGL, and XDH genes in the liver was lower during hibernation than that during the other periods. These results indicate that E. multiocellata living in low-altitude desert areas displays a reduced dependence upon oxidative metabolism relative to S. tsinlingensis living in high-altitude mountain areas. The oxidative stress resistance and metabolic levels of E. multiocellata showed an adaptive response to seasons. Antioxidant enzyme activities in the liver were broadly up-regulated during the arousal period but not during the hibernating period, which may be associated with restored metabolism during the arousal period. These results enrich our understanding of lizards’ adaptabilities to oxidative stress.

Key words: oxidative stress, hibernation, lizard, metabolism, environment.