title: DNA damage, histological changes and DNA repair in larval Japanese medaka (Oryzias latipes) exposed to ultraviolet-B radiation.
abstract: Cyclobutane dimer formation, photorepair capability and histological damage were compared among four differently pigmented strains of larval Japanese medaka (Oryzias latipes) to determine whether pigmentation modifies the level of UV-B radiation (290-320 nm) inducible damage in these fish. One-day post-hatch medaka were exposed to one of several UV-B fluence rates with or without photoreactivating light for 5 days for 7 h per day. Their DNA was extracted for analysis by ELISA for cyclobutane pyrimidine dimers or the larvae were processed for histological examination. At the higher UV-B fluence rates tested, wild-type melanophore-containing medaka formed significantly more dimers than at least one of the other strains tested. Wild-type medaka also showed significantly less photorepair capability than the white melanophore-lacking medaka. The wild-type larvae had significantly more necrosis than the orange-red melanophore-lacking larvae at the lower UV-B fluence rate tested and at the higher fluence rate used, the wild-type medaka also exhibited significantly more necrosis than the white melanophore-lacking larvae. Of the 19 medaka observed with cellular hyperplasia, six were wild-type. These six individual larvae showed the greatest degree of cellular hyperplasia. Cellular hyperplasia appeared to be greatest at the lowest UV-B fluence rate used. The presence of melanophores in the wild-type medaka may have contributed to an increased level of tissue damage in this strain when compared to the other strains.
authors.affiliation: BBL Sciences, 326 First Street, Suite 200, Annapolis, MD 21403-2678, USA. ta@bbl-inc.com
authors.forename: Tina N
authors.initials: TN
authors.lastname: Armstrong
authors.forename: Renate
authors.initials: R
authors.lastname: Reimschuessel
authors.forename: Brian P
authors.initials: BP
authors.lastname: Bradley
mesh_terms: D000818:Animals; D004249:DNA Damage; D004260:DNA Repair / Q000528:radiation effects*; D004277:DNA, Single-Stranded / Q000528:radiation effects; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D004817:Epidermis / Q000196:embryology / Q000473:pathology / Q000528:radiation effects; D006965:Hyperplasia; D007150:Immunohistochemistry; D020300:Intracranial Hemorrhages / Q000196:embryology / Q000209:etiology; D007814:Larva / Q000528:radiation effects; D008027:Light; D008547:Melanophores / Q000502:physiology; D009336:Necrosis; D009990:Oryzias / Q000033:anatomy & histology / Q000235:genetics*; D011740:Pyrimidine Dimers / Q000096:biosynthesis / Q000528:radiation effects; D012880:Skin Pigmentation / Q000502:physiology*; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D004277:DNA, Single-Stranded; D011740:Pyrimidine Dimers