title: Evaluation of spontaneous recovery of behavioral and brain injury profiles in zebrafish after hypoxia.
abstract: Cerebral hypoxia-ischemia can lead to motor and sensory impairments which can be dependent on the extent of infarcted regions. Since a better understanding of the neurochemical mechanisms involved in this injury is needed, the use of zebrafish as a cerebral hypoxia model has become quite promising because it could improve the knowledge about hypoxia-ischemia. In the current study, we aimed to investigate the spontaneous recovery of brain and behavioral impairments induced by hypoxia in adult zebrafish. Brain injury levels were analyzed by spectrophotometric measurement of mitochondrial dehydrogenase activity by staining with 2,3,5-triphenyltetrazolium chloride, and behavioral profiles were assessed by the open tank test. The induction of hypoxia substantially decreased mitochondrial activity in the brain and impaired behavior. The spontaneous recovery of fish subjected to hypoxia was assessed after 1, 3, 6, 24, and 48h under normoxia. The quantification of brain injury levels showed a significant increase until 24h after hypoxia, but after 48h this effect was completely reversed. Regarding behavioral parameters, we verified that locomotor activity and vertical exploration were impaired by hypoxia and these effects were reversed after 3h under normoxia. Taken together, these results show that zebrafish exhibited transient cerebral and behavioral impairments when submitted to hypoxia, and 1h under normoxic conditions was insufficient to reverse both effects. Therefore, our data help to elucidate the time window of spontaneous recovery in zebrafish after hypoxia and also the behavioral phenotypes involved in this phenomenon.
authors.affiliation: Programa de Pós-graduação em Bioquímica, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600-Anexo, 90035-003 Porto Alegre, RS, Brazil. marcosmbraga@gmail.com
authors.forename: Marcos M
authors.initials: MM
authors.lastname: Braga
authors.forename: Eduardo P
authors.initials: EP
authors.lastname: Rico
authors.forename: Sandro D
authors.initials: SD
authors.lastname: Córdova
authors.forename: Charles B
authors.initials: CB
authors.lastname: Pinto
authors.forename: Rachel E
authors.initials: RE
authors.lastname: Blaser
authors.forename: Renato D
authors.initials: RD
authors.lastname: Dias
authors.forename: Denis B
authors.initials: DB
authors.lastname: Rosemberg
authors.forename: Diogo L
authors.initials: DL
authors.lastname: Oliveira
authors.forename: Diogo O
authors.initials: DO
authors.lastname: Souza
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001921:Brain / Q000473:pathology*; D004396:Coloring Agents; D005106:Exploratory Behavior / Q000502:physiology; D005260:Female; D002534:Hypoxia, Brain / Q000473:pathology* / Q000523:psychology*; D008297:Male; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism; D009043:Motor Activity / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology*; D013550:Swimming / Q000502:physiology; D013778:Tetrazolium Salts / Q000494:pharmacology; D015027:Zebrafish / Q000502:physiology*
chemical_list: D004396:Coloring Agents; D013778:Tetrazolium Salts; C009591:triphenyltetrazolium
keywords: Behavior; Brain; Hypoxia; Spontaneous recovery; Zebrafish