Physiological and Biochemical Adaptations to High Altitude in Tibetan Frogs, Nanorana parkeri

• Published in: Frontiers in physiology Vol. 13; p. 942037
• Main Authors: Niu, Yonggang, Zhang, Xuejing, Xu, Tisen, Li, Xiangyong, Zhang, Haiying, Wu, Anran, Storey, Kenneth B., Chen, Qiang
• Format: Journal Article
• Language: English
• Published: Frontiers Media S.A 06.07.2022
• Subjects: antioxidant defense; hematological parameters; high-altitude; Nanorana parkeri; oxidative stress; Physiology
• ISSN: 1664-042X; 1664-042X
• DOI: 10.3389/fphys.2022.942037

The Xizang plateau frog, N. parkeri (Anura: Dicroglossidae), is endemic to the Tibetan Plateau, ranging from 2,850 to 5,100 m above sea level. The present study explores physiological and biochemical adaptations to high altitude in this species with a particular emphasis on parameters of hematology, oxidative stress, and antioxidant defense in adult and juvenile N. parkeri collected from high (4,600 m a.s.l) and low (3,400 m a.s.l) altitudes. Hematological results showed that hemoglobin concentration ([Hb]), hematocrit (Hct), and red blood cell (RBC) counts were significantly higher in high-altitude N. parkeri . High-altitude juveniles had lower RBC sizes than low-altitude juveniles. Higher levels of GSH and GSSG were indicated only in juveniles from high altitude, not in adults. High-altitude individuals also showed lower oxidative damage, assessed as malondialdehyde (MDA) and carbonyl groups (CG) in the liver. High-altitude adults also showed higher activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and glutathione-S-transferase (GST) as well as total antioxidant capacity (T-AOC) in the liver as compared to low-altitude adults. Moreover, higher GPX activity and T-AOC were observed in the heart and brain of high-altitude adults. Liver CAT, GPX, and T-AOC showed significant increases in high-altitude juveniles. Vitamin C content was also higher in the heart of high-altitude frogs compared to low-altitude individuals. In summary, the high-altitude population of N. parkeri showed more robust hematological parameters, less oxidative damage, and stronger antioxidant defenses than the low-altitude population, all contributing to increased protection for survival in high-altitude environments.