title: L-arginine reduces mercury accumulation in thymus of mercury-exposed mice: role of nitric oxide synthase activity and metallothioneins.
abstract: Mercury, an occupational and environmental contaminant, is a well-recognized health hazard. The thymus is a target for inorganic mercury (Hg2+); thymic function is impaired in Hg2+ intoxication and is partially restored by simultaneous L-arginine supplementation. The nitric oxide (NO)-nitric oxide synthase (NOS) pathway and metallothioneins (MTs) were studied to investigate the role of L-arginine in thymic function restoration after mercury exposure. Mice received a higher and a lower dose of inorganic mercury, with and without L-arginine supplementation. Saline-treated mice were used as controls. Thymus weight and thymulin were measured as indices of thymic function. Mice treated with Hg2+ alone displayed an accumulation of metal in the thymus, reduced NOS activity, a lower plasma nitrite plus nitrate concentration and an increased MTs expression compared with control mice. L-arginine supplementation was associated with lower Hg2+ concentrations in the organ and partial preservation of other measures. Reduced accumulation of Hg2+ in mice dosed with L-arginine was probably related to greater NO production and NO-MTs interactions.
authors.affiliation: Department of Molecular Pathology and Innovative Therapies, Occupational Medicine, Polytechnic University of Marche, Ancona, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Bracci
authors.forename: Marco
authors.initials: M
authors.lastname: Tomasetti
authors.forename: Marco
authors.initials: M
authors.lastname: Malavolta
authors.forename: Viviana
authors.initials: V
authors.lastname: Bonacucina
authors.forename: Eugenio
authors.initials: E
authors.lastname: Mocchegiani
authors.forename: Lory
authors.initials: L
authors.lastname: Santarelli
mesh_terms: D000818:Animals; D001120:Arginine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008628:Mercury / Q000008:administration & dosage* / Q000032:analysis / Q000494:pharmacology; D008630:Mercury Poisoning / Q000188:drug therapy / Q000503:physiopathology*; D008668:Metallothionein / Q000187:drug effects*; D051379:Mice; D008807:Mice, Inbred BALB C; D019001:Nitric Oxide Synthase / Q000187:drug effects*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013950:Thymus Gland / Q000187:drug effects* / Q000503:physiopathology
chemical_list: D008668:Metallothionein; D001120:Arginine; D019001:Nitric Oxide Synthase; D008628:Mercury