title: Genotoxic and cytotoxic effects of manganese chloride in cultured human lymphocytes treated in different phases of cell cycle.
abstract: Manganese (Mn) has a natural occurrence and is necessary during the initial periods of the development. However, in high concentrations, Mn can be related to neurodegenerative disorders. The aim of the present study was to evaluate the mutagenic potential of manganese chloride (MnCl2.4H2O). Comet assay and chromosome aberrations analysis were applied to determine the DNA-damaging and clastogenic effects of MnCl2.4H2O. Cultured human lymphocytes were treated with 15, 20 and 25 microM manganese chloride during the G1, G1/S, S (pulses of 1 and 6h), and G2 phases of the cell cycle. All tested concentrations were cytotoxic and reduced significantly the mitotic index in G1, G1/S and S (1 and 6h) treatments, while in G2 treatment only the higher concentrations (20 and 25 microM) showed cytotoxic effects. Clastogenicity and DNA damage were found only in treatments with the highest concentration (25 microM). Chromosome aberrations were found exclusively in the G2 phase of the cell cycle. The absence of polyploidy in mitosis, suggests that manganese does not affect the formation of the mitotic spindle with the concentrations tested. The genotoxicity found in G2 phase and in the comet assay can be related to the short time of treatment in both cases.
authors.affiliation: Human Cytogenetics Laboratory, Institute of Biological Sciences, Federal University of Pará, Av. Augusto Correa, 01, CEP 66075-110 Belém, Pará, Brazil.
authors.forename: P D L
authors.initials: PD
authors.lastname: Lima
authors.forename: M C
authors.initials: MC
authors.lastname: Vasconcellos
authors.forename: M O
authors.initials: MO
authors.lastname: Bahia
authors.forename: R C
authors.initials: RC
authors.lastname: Montenegro
authors.forename: C O
authors.initials: CO
authors.lastname: Pessoa
authors.forename: L V
authors.initials: LV
authors.lastname: Costa-Lotufo
authors.forename: M O
authors.initials: MO
authors.lastname: Moraes
authors.forename: R R
authors.initials: RR
authors.lastname: Burbano
mesh_terms: D002453:Cell Cycle / Q000187:drug effects*; D002478:Cells, Cultured; D002712:Chlorides / Q000008:administration & dosage / Q000633:toxicity*; D002869:Chromosome Aberrations / Q000187:drug effects; D020552:Comet Assay; D004785:Environmental Pollutants / Q000008:administration & dosage / Q000633:toxicity*; D006801:Humans; D008214:Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D017895:Manganese Compounds / Q000008:administration & dosage; D008940:Mitotic Index; D009152:Mutagenicity Tests; D009153:Mutagens / Q000008:administration & dosage / Q000633:toxicity; D013997:Time Factors
chemical_list: D002712:Chlorides; D004785:Environmental Pollutants; D017895:Manganese Compounds; D009153:Mutagens; C025340:manganese chloride