title: The effects of UV radiation on the visual system of the crab Neohelice granulata: a protective role of melatonin.
abstract: The first and main target-structure of ultraviolet (UV) radiation in animals is the body surface, including the skin and eyes. Here, we investigated cell damage in the visual system of the crab Neohelice granulata acclimated to constant light and exposed to UVA or UVB at 12:00 h for 30 min. The reactive oxygen species (ROS) production, antioxidant capacity against peroxyl radicals (ACAP), lipid peroxidation (LPO) damage, catalase (CAT) activity, and the melatonin immunohistochemical reactivity in the eyestalks were evaluated. The animals that received melatonin and were exposed to UVA and UVB radiation showed a decreased ROS concentration (p<0.05).The ACAP test showed a decrease (p<0.05) in their values when the animals received 2 pmol/crab of melatonin (physiological dose) before the exposure to UVA radiation. The animals exposed to UVB radiation after receiving the same dose of melatonin showed an increase (p<0.05) in the ACAP test compared with the animals exposed to UVB radiation after receiving only crab physiological saline. The CAT activity increased (p<0.05) in the animals that received melatonin and were exposed to UVA and UVB radiation. Animals exposed to UVA and UVB displayed an increase (p<0.05) in the LPO levels, whereas animals treated with melatonin showed lower (p<0.05) LPO levels when irradiated. The results indicate that the specific oxidative parameters altered by UV radiation can be modulated by a physiological dose of melatonin. Moreover, the melatonin regularly produced by virtually all eyestalk cells suggests that it may function to modulate the noxious effects of radiation, at least in the crab N. granulata.
authors.affiliation: Programa de Pós-Graduação em Ciências Morfológicas, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro - UFRJ, 21941-590 Rio de Janeiro, RJ, Brazil.
authors.forename: Marcelo Alves
authors.initials: MA
authors.lastname: Vargas
authors.forename: Márcio Alberto
authors.initials: MA
authors.lastname: Geihs
authors.forename: Fábio Everton
authors.initials: FE
authors.lastname: Maciel
authors.forename: Bruno Pinto
authors.initials: BP
authors.lastname: Cruz
authors.forename: Luiz Eduardo Maia
authors.initials: LE
authors.lastname: Nery
authors.forename: Silvana
authors.initials: S
authors.lastname: Allodi
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D003386:Brachyura / Q000187:drug effects / Q000528:radiation effects; D002374:Catalase / Q000378:metabolism; D005123:Eye / Q000528:radiation effects*; D015227:Lipid Peroxidation / Q000528:radiation effects; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D000975:Antioxidants; D011837:Radiation-Protective Agents; D017382:Reactive Oxygen Species; D002374:Catalase; D008550:Melatonin