title: Antioxidant defenses and DNA damage induced by UV-A and UV-B radiation in the crab Chasmagnathus granulata (Decapoda, Brachyura).
abstract: The photoprotector role of pigment dispersion in the melanophores of the crab, Chasmagnathus granulata, against DNA and oxidative damages caused by UV-A and UV-B was investigated. Intact and eyestalkless crabs were used. In eyestalkless crabs, the dorsal epidermis of the cephalothorax (dispersed melanophores) and the epidermis of pereiopods (aggregated melanophores) were analyzed. Intact crabs showed only dispersed melanophores in the two epidermis. Antioxidant enzymes activity and lipoperoxidation content were analyzed after UV-A (2.5 J/cm2) or UV-B (8.6 J/cm2) irradiation. DNA damage was analyzed by single cell electrophoresis (comet) assay, after exposure to UV-B (8.6 J/cm2). UV-A radiation increased the glutatione-S-transferase activity in the pereiopods epidermis of eyestalkless crabs (P<0.05). UV-B radiation induced DNA damage in the dorsal epidermis of eyestalkless crabs (P<0.05). In pereiopod epidermis of eyestalkless crabs, there was no significant difference between control and UV-B-exposed crabs. In the pereiopods epidermis of eyestalkless, the control group showed higher scores of DNA damage and approximately 50% of cellular viability. Because in eyestalkless and irradiated crabs the cellular viability was approximately 5%, it was not possible to observe nuclei for determination of DNA damage. The findings show that melanophores can play a role in the defense against harmful effects of a momentary exposure to UV radiation.
authors.affiliation: Fundação Universidade Federal do Rio Grande-FURG, Departamento de Ciências Fisiológicas, Programa de Pós-graduação em Ciências Fisiológicas-Fisiologia Animal Comparada, Rio Grande, Rio Grande do Sul, Brazil.
authors.forename: Glauce R
authors.initials: GR
authors.lastname: Gouveia
authors.forename: Daiane S
authors.initials: DS
authors.lastname: Marques
authors.forename: Bruno P
authors.initials: BP
authors.lastname: Cruz
authors.forename: Laura A
authors.initials: LA
authors.lastname: Geracitano
authors.forename: Luiz E M
authors.initials: LE
authors.lastname: Nery
authors.forename: Gilma S
authors.initials: GS
authors.lastname: Trindade
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism / Q000528:radiation effects*; D002374:Catalase / Q000378:metabolism / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects; D004247:DNA / Q000187:drug effects / Q000528:radiation effects; D004249:DNA Damage; D033364:Decapoda / Q000737:chemistry / Q000201:enzymology* / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004817:Epidermis / Q000737:chemistry / Q000528:radiation effects; D005982:Glutathione Transferase / Q000378:metabolism / Q000528:radiation effects*; D015227:Lipid Peroxidation / Q000528:radiation effects; D008547:Melanophores / Q000737:chemistry / Q000502:physiology; D010860:Pigments, Biological / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D000975:Antioxidants; D010860:Pigments, Biological; D004247:DNA; D002374:Catalase; D005982:Glutathione Transferase