title: Hypoxia acclimation protects against oxidative damage and changes in prolactin and somatolactin expression in silver catfish (Rhamdia quelen) exposed to manganese.
abstract: The aim of this study was to assess the Mn toxicity to silver catfish considering Mn accumulation and oxidative status in different tissues, as well as pituitary hormone expression after acclimation to hypoxia. Silver catfish acclimated to hypoxia for 10 days and successively exposed to Mn (9.8 mg L(-1)) for an additional 10 days exhibited lower Mn accumulation in plasma, liver, kidneys and brain and prevented the hematocrit decrease observed in the normoxia group. Hypoxia acclimation also modified Mn-induced oxidative damage, which was observed by lower reactive species (RS) generation in gills and kidneys, decreased lipid peroxidation (LP) levels in gills, liver and kidneys and decreased protein carbonyl (PC) levels in liver, kidneys and brain. Manganese accumulation showed positive correlations with LP levels in gills and kidneys, as well as with PC levels in gills, liver and brain. In addition, hypoxia acclimation and Mn exposure increased catalase (CAT) activity in gills and kidneys and Na(+)/K(+)-ATPase activity in gills, liver and brain. Silver catfish that were acclimated under normoxia and exposed to Mn displayed increased pituitary prolactin (PRL) and decreased somatolactin (SL) expression. Interestingly, hypoxia acclimation prevented hormonal fluctuation of PRL and SL in fish exposed to Mn. These findings indicate that while the exposure of silver catfish to Mn under normoxia was related to metal accumulation and oxidative damage in tissues together with endocrine axis disruption, as represented by PRL and SL, hypoxia acclimation reduced waterborne Mn uptake, thereby minimizing oxidative damage and changes in hormonal profile. We hypothesized that moderate hypoxia is able to generate adaptive responses, which may be related to hormesis, thereby ameliorating Mn toxicity to silver catfish.
authors.affiliation: Programa de Pós Graduação em Farmacologia - UFSM, Brazil.
authors.forename: G S
authors.initials: GS
authors.lastname: Dolci
authors.affiliation: Programa de Pós Graduação em Farmacologia - UFSM, Brazil.
authors.forename: L T
authors.initials: LT
authors.lastname: Vey
authors.affiliation: Departamento de Fisiologia e Farmacologia - UFSM, Brazil.
authors.forename: A J
authors.initials: AJ
authors.lastname: Schuster
authors.affiliation: Departamento de Fisiologia e Farmacologia - UFSM, Brazil.
authors.forename: Kr
authors.initials: K
authors.lastname: Roversi
authors.affiliation: Programa de Pós Graduação em Farmacologia - UFSM, Brazil.
authors.forename: K
authors.initials: K
authors.lastname: Roversi
authors.affiliation: Departamento de Fisiologia e Farmacologia - UFSM, Brazil.
authors.forename: V T
authors.initials: VT
authors.lastname: Dias
authors.affiliation: Programa de Pós Graduação em Farmacologia - UFSM, Brazil.
authors.forename: C S
authors.initials: CS
authors.lastname: Pase
authors.affiliation: Programa de Pós Graduação em Farmacologia - UFSM, Brazil.
authors.forename: R C S
authors.initials: RC
authors.lastname: Barcelos
authors.affiliation: Programa de Pós Graduação em Farmacologia - UFSM, Brazil.
authors.forename: C T D
authors.initials: CT
authors.lastname: Antoniazzi
authors.affiliation: Programa de Pós Graduação em Farmacologia - UFSM, Brazil.
authors.forename: J I
authors.initials: JI
authors.lastname: Golombieski
authors.affiliation: Programa de Pós Graduação em Medicina Veterinária - UFSM, Brazil.
authors.forename: W G
authors.initials: WG
authors.lastname: Glanzner
authors.affiliation: Programa de Pós-Graduação em Química - UFSM, Brazil; Departamento de Clínica de Grandes Animais - UFSM, Brazil.
authors.forename: P A
authors.initials: PA
authors.lastname: Anezi Junior
authors.affiliation: Programa de Pós-Graduação em Química - UFSM, Brazil; Programa de Pós Graduação em Medicina Veterinária - UFSM, Brazil; Departamento de Clínica de Grandes Animais - UFSM, Brazil.
authors.forename: P B D
authors.initials: PB
authors.lastname: Gonçalves
authors.affiliation: Programa de Pós-Graduação em Química - UFSM, Brazil; Departamento de Clínica de Grandes Animais - UFSM, Brazil.
authors.forename: M A G
authors.initials: MA
authors.lastname: Nunes
authors.affiliation: Programa de Pós-Graduação em Química - UFSM, Brazil; Departamento de Clínica de Grandes Animais - UFSM, Brazil.
authors.forename: V L
authors.initials: VL
authors.lastname: Dressler
authors.affiliation: Programa de Pós Graduação em Farmacologia - UFSM, Brazil; Departamento de Fisiologia e Farmacologia - UFSM, Brazil.
authors.forename: B
authors.initials: B
authors.lastname: Baldisserotto
authors.affiliation: Programa de Pós Graduação em Farmacologia - UFSM, Brazil; Departamento de Fisiologia e Farmacologia - UFSM, Brazil. Electronic address: mariliseeb@yahoo.com.br.
authors.forename: M E
authors.initials: ME
authors.lastname: Burger
mesh_terms: D000064:Acclimatization; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D002374:Catalase / Q000378:metabolism; D002397:Catfishes / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D029941:Fish Proteins / Q000235:genetics*; D005786:Gene Expression Regulation / Q000187:drug effects*; D005880:Gills / Q000378:metabolism; D006023:Glycoproteins / Q000235:genetics*; D000860:Hypoxia / Q000378:metabolism*; D008345:Manganese / Q000633:toxicity*; D010084:Oxidation-Reduction; D010902:Pituitary Gland / Q000187:drug effects*; D010907:Pituitary Hormones / Q000235:genetics*; D011388:Prolactin / Q000235:genetics*; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D029941:Fish Proteins; D006023:Glycoproteins; D010907:Pituitary Hormones; D014874:Water Pollutants, Chemical; C064448:somatolactin protein, fish; D008345:Manganese; D011388:Prolactin; D002374:Catalase; D000251:Adenosine Triphosphatases
keywords: Hormesis; Manganese; Moderate hypoxia; Na(+)/K(+)-ATPase; Oxidative stress; Pituitary hormones expression