title: A time-course study of immune response in Japanese flounder Paralichthys olivaceus exposed to heavy oil.
abstract: OBJECTIVE
  The immunotoxicities of oil and its components on fish immunities have been investigated, but there is little literature on the recovery of the fish from the immune suppression. Therefore, the recovery of Japanese flounder Paralichthys olivaceus from an immunosuppressive effect due to heavy oil (HO) exposure was investigated in this study.
  
  
  METHODS
  Fish were exposed to HO at a concentration of 0.385 g/L for 2 days, while control fish received no exposure. Seven fish were sampled at 0, 3, 7, and 14 days post-exposure. The respiratory rate was measured everyday as an indicator of the acute effect of HO exposure. Fish serum was collected and used for antibacterial activity assay against Edwardsiella tarda. Expression changes of respiratory and immune-related genes were evaluated by real-time PCR.
  
  
  CONCLUSIONS
  The respiratory rate was significantly increased in the HO-exposed group until 4 days post-exposure. A respiratory-related gene, β-hemoglobin, was also significantly downregulated in the spleen both at 0 and 7 days post-exposure and kidney at 3 days post-exposure in HO-exposed fish. Immunotoxicity, including suppression of antibacterial activities and downregulation of the IgM gene, was observed in HO-exposed fish until 3 days post-exposure, but not after that time. From these results, we conclude that the fish likely return to normal status around 1 week.
authors.affiliation: Graduate School of Science and Engineering, Ehime University, Matsuyama 790-8577, Japan.
authors.forename: Jun-Young
authors.initials: JY
authors.lastname: Song
authors.forename: Sho
authors.initials: S
authors.lastname: Ohta
authors.forename: Kei
authors.initials: K
authors.lastname: Nakayama
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Murakami
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Kitamura
mesh_terms: D000818:Animals; D020609:Edwardsiella tarda / Q000276:immunology; D004756:Enterobacteriaceae Infections / Q000276:immunology / Q000662:veterinary; D005393:Fish Diseases / Q000139:chemically induced / Q000276:immunology / Q000382:microbiology; D005432:Flounder / Q000276:immunology* / Q000502:physiology; D006454:Hemoglobins / Q000187:drug effects / Q000235:genetics; D007075:Immunoglobulin M / Q000187:drug effects / Q000235:genetics; D009113:Muramidase / Q000187:drug effects / Q000235:genetics; D010578:Petroleum / Q000633:toxicity*; D060888:Real-Time Polymerase Chain Reaction; D012119:Respiration / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D006454:Hemoglobins; D007075:Immunoglobulin M; D010578:Petroleum; D014874:Water Pollutants, Chemical; D009113:Muramidase