The Adaptation Of Phrynocephalus Vlangalii To Oxidative Stress At High Altitude

Oxidative stress and oxidative damage have been huge challenges of survival for animals living on the plateau at different stages, however, lifelong exposure to high altitude could generate certain adaptability which makes them more tolerant to these environments. Phrynocephalus vlangalii is an abundant lizard on the Tibetan plateau inhabiting along a wide elevation gradient from 2500 m to 4800 m above sea level. Thus, the aim of the present study was to compare the baseline information of oxidative stress indicators in Phrynocephalus vlangalii between low altitude (LA, 2900m) and high altitude (HA,4200m). Tissues were analyzed for catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione reductase (GR), total antioxidant capacity(T-AOC), Vitamin C, Vitamin E and lipid peroxidation (measured as malondiadehyde, MDA). The results showed that the MDA levels in lizards at HA decreased significantly in brain, but markedly increased in muscle and had no significant difference in liver as compared to that in lizards at LA. The activity of CAT in brain was dramatically increased along an elevational gradient. In livers, results of the specific levels of different antioxidants but T-AOC and GR were similar between both elevations. The levels of T-AOC and GR for lizards at LA were dramatically higher than lizards at HA. By contrast, the most antioxidants levels (SOD, GPX, GR, T-AOC, Vit C) decreased markedly in muscle with elevation. We also explore the effects of hypoxia on oxidative damage and antioxidant defenses in P. vlangalii. The lizards were acclimatized in simulated hypoxic chamber (15% O2 and 8% O2) for 6 weeks. The dates showed that the levels of MDA, CAT, GSH (Glutathione) and T-AOC in brain and MDA, CAT and SOD in liver in 8% O2 group were significantly higher man the 15% O2 group. These findings indicate that the lizards show differences in oxidative metabolism among tissues at different altitude and could mount an adaptive response to hypoxia-mediated oxidative stress.