Effects of ultraviolet B on epidermal morphology, shedding, lipid peroxide, and antioxidant enzymes in the lizard Phrynocephalus przewalskii (Agamidae)(In English)

摘要

Lizards Phrynocephalus przewalskii use sunlight to increase their body temperature simultaneously increasing the risk of skin damage by ultraviolet B (UVB) irradiation. We investigated the effects of UVB irradiation (110, 300, 500 and 800 mJ/cm², respectively) on epidermal morphology, lipid peroxide, and antioxidant enzymes in their skin. Results showed that the peak of epidermal damage and malondialdehyde (MDA) content occurred 96, 48 or 24 h after exposure to 300, 500 and 800 mJ/cm² of UVB radiation, respectively. The lowest superoxide dismutase (SOD) activity occurred 24, 48, 12 and 12 h after exposure to 110, 300, 500 and 800 mJ/cm² of UVB, respectively. Catalase (CAT) activity was inhibited immediately, then gradually recovered and the highest CAT levels accompanied the most serious damage of skin morphology. Later on, CAT activity decreased and then even increased to peak levels above control level, which was accompanied by shedding of the damaged epidermal complex. This indicates that epidermal damage induced by UVB is closely related to lipid peroxidation, where CAT acts as a primary antioxidant enzyme. Moreover, the keratinous layer protects the viable cell layer against UVB damage as well [ Acta Zoologica Sinica 动物学报 wuxuebaoica Sinica52(3): 52(3):542 –550, 2006].