title: Assessment of methyl methacrylate genotoxicity by the micronucleus test.
abstract: The aim of this study was to evaluate the genotoxic potential of methyl methacrylate (MMA) vapor by simulating standard occupational exposure of 8 hours per day and using the micronucleus test. We used 32 adult male Wistar rats divided into three groups: A - 16 rats exposed to MMA for 8 hours a day, B - Eight rats receiving single subcutaneous doses of cyclophosphamide on the first day of the experiment (positive control), C - Eight rats receiving only water and food ad libitum (negative control). Eight rats from group A and all of the rats from groups B and C were sacrificed 24 hours after beginning the experiment (acute exposure in group A). The remaining animals in group A were sacrificed 5 days after the experiment began (repeated exposure assessment in group A, simulating occupational exposure 40 hours/week). Femoral bone marrow was collected from each rat at the time of sacrifice for use in the micronucleus test. Two slides were completed per animal and were stained with Giemsa staining. Two thousand polychromatic erythrocytes were counted per animal. The Kruskal-Wallis test followed by a multiple comparisons test (Dunn test) was used for statistical analysis. The median number of micronuclei was 7.00 in the group exposed to MMA for 1 day, 2.00 in the group exposed to MMA for 5 days, 9.00 in the group exposed to cyclophosphamide (positive control) and 0.756 in the negative control group (p < 0.0001). MMA was genotoxic when measured after 1 day of exposure but was not evidently genotoxic after 5 days.
authors.affiliation: Univ do Oeste Paulista, SP, Brazil.
authors.forename: Amarildo Mariano de
authors.initials: AM
authors.lastname: Araújo
authors.forename: Guilherme Rodrigues
authors.initials: GR
authors.lastname: Alves
authors.forename: Guilherme Trevisan
authors.initials: GT
authors.lastname: Avanço
authors.forename: José Luiz Santos
authors.initials: JL
authors.lastname: Parizi
authors.forename: Gisele Alborghetti
authors.initials: GA
authors.lastname: Nai
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000187:drug effects; D003738:Dental Cements / Q000633:toxicity*; D003764:Dental Materials / Q000633:toxicity; D004912:Erythrocytes / Q000187:drug effects; D005269:Femur / Q000187:drug effects; D005740:Gases / Q000633:toxicity; D008297:Male; D020366:Methylmethacrylate / Q000633:toxicity*; D015162:Micronucleus Tests; D016273:Occupational Exposure / Q000009:adverse effects; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
chemical_list: D003738:Dental Cements; D003764:Dental Materials; D005740:Gases; D020366:Methylmethacrylate