Acute Thermal Elevation Alters Cellular Metabolic Activity, Redox Balance, and Iron Homeostasis in Butterfly Lizards (Leiolepis belliana belliana).

Global warming is increasing the frequency of acute temperature fluctuations that may threaten ectothermic reptiles, but the underlying physiological and cellular mechanisms remain poorly understood. This study investigated physiological changes, oxidative imbalance, antioxidant systems, nitric oxide, iron metabolism, and red blood cell morphology in butterfly lizards (Leiolepis belliana belliana) under acute temperature elevation. Physiological responses were evaluated in vivo in butterfly lizards exposed to temperatures of 27-37 °C, whereas biochemical responses in red blood cells were examined in vitro at 27-39 °C, and red blood cell morphology was evaluated at 27-37 °C. Body temperature (p = 0.00000107) and pulse rate (p = 0.00000147) increased significantly with increasing temperature, whereas respiratory rate (p = 0.4185) and blood oxygen saturation (p = 0.7672) were not significantly affected. In blood cells, cellular metabolic activity (p = 0.00000674), malondialdehyde (p = 0.000256), protein oxidation (p = 0.0000526), ferric iron (p = 0.000000105), and vitamin E (p = 0.000464) increased significantly, whereas total antioxidant capacity (p = 0.0000000896), glutathione (p = 0.000453), nitric oxide (p = 0.000000252), and ferrous iron (p = 0.0000000182) decreased significantly. Hydrogen peroxide (p = 0.000181), glutathione peroxidase activity (p = 0.000000169), and catalase activity (p = 0.00000182) also showed significant temperature-dependent changes. Red blood cell elongation increased significantly (p = 0.0005), whereas nucleus size remained unchanged (nucleus length, p = 0.6800; nucleus width, p = 0.8814). Acute temperature elevation increased cellular metabolic activity and was accompanied by impaired antioxidant defense, oxidative damage, disruption of nitric oxide homeostasis, and iron dysregulation in butterfly lizard red blood cells. These findings improve our understanding of the cellular mechanisms underlying acute heat stress in ectothermic reptiles.