title: Persistent oxytetracycline exposure induces an inflammatory process that improves regenerative capacity in zebrafish larvae.
abstract: BACKGROUND
  The excessive use of antibiotics in aquaculture can adversely affect not only the environment, but also fish themselves. In this regard, there is evidence that some antibiotics can activate the immune system and reduce their effectiveness. None of those studies consider in detail the adverse inflammatory effect that the antibiotic remaining in the water may cause to the fish. In this work, we use the zebrafish to analyze quantitatively the effects of persistent exposure to oxytetracycline, the most common antibiotic used in fish farming.
  
  
  METHODS
  We developed a quantitative assay in which we exposed zebrafish larvae to oxytetracycline for a period of 24 to 96 hrs. In order to determinate if the exposure causes any inflammation reaction, we evaluated neutrophils infiltration and quantified their total number analyzing the Tg(mpx:GFP)(i114) transgenic line by fluorescence stereoscope, microscope and flow cytometry respectively. On the other hand, we characterized the process at a molecular level by analyzing several immune markers (il-1β, il-10, lysC, mpx, cyp1a) at different time points by qPCR. Finally, we evaluated the influence of the inflammation triggered by oxytetracycline on the regeneration capacity in the lateral line.
  
  
  CONCLUSIONS
  Our results suggest that after 48 hours of exposure, the oxytetracycline triggered a widespread inflammation process that persisted until 96 hours of exposure. Interestingly, larvae that developed an inflammation process showed an improved regeneration capacity in the mechanosensory system lateral line.
authors.affiliation: Departamento de Ciencias Biologicas, Facultad de Ciencias Biologicas, Universidad Andres Bello, Santiago, Chile.
authors.forename: Francisco
authors.initials: F
authors.lastname: Barros-Becker
authors.forename: Jaime
authors.initials: J
authors.lastname: Romero
authors.forename: Alvaro
authors.initials: A
authors.lastname: Pulgar
authors.forename: Carmen G
authors.initials: CG
authors.lastname: Feijóo
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D000900:Anti-Bacterial Agents / Q000009:adverse effects* / Q000494:pharmacology; D015415:Biomarkers; D005393:Fish Diseases / Q000139:chemically induced / Q000235:genetics / Q000276:immunology*; D007249:Inflammation / Q000139:chemically induced / Q000276:immunology / Q000662:veterinary; D010118:Oxytetracycline / Q000009:adverse effects* / Q000494:pharmacology; D012038:Regeneration / Q000187:drug effects* / Q000276:immunology; D015027:Zebrafish / Q000235:genetics / Q000276:immunology*
chemical_list: D000900:Anti-Bacterial Agents; D015415:Biomarkers; D010118:Oxytetracycline