title: Suppressive effects of methyl methacrylate on the mutagenicity and DNA adduct formation induced by 1-nitropyrene and benzo[a]pyrene.
abstract: Methyl methacrylate (MMA) is widely used as a cement in dentistry, orthopaedic surgery and ophthalmology. Studies based on short-term genotoxicity tests have produced conflicting results in the last two decades. In the present study, the effects of MMA on the mutagenicity of 1-nitropyrene (1-NP) and benzo[a]pyrene (B[a]P) were evaluated with the Salmonella typhimurium TA98 strain in the absence and presence of S9 mix. The direct-acting mutagenicity of 1-NP was markedly decreased by MMA in a dose-dependent manner. However, a low inhibitory effect of MMA on the metabolic-acting mutagenicity of B[a]P was observed. MMA did not show mutagenicity within the concentrations of 4.7-37.6 microM either with or without S9 mix. The inhibitory effect of MMA was not due to its cytotoxicity because very low and/or no cytotoxicity of MMA to S. typhimurium TA98 was observed. To confirm the antimutagenicity of MMA against 1-NP and B[a]P, a 32P-postlabelling method was used to determine whether MMA modified DNA adduct formation produced by both compounds in calf thymus DNA. MMA inhibits the formation of 1-NP- and B[a]P-DNA adducts in a dose-dependent manner. The DNA adduct of 1-NP reduced by MMA was greater than that of B[a]P. Thus, we suggested that MMA was possibly acting as an inhibitor of chemical carcinogenesis.
authors.affiliation: Department of Dentistry, Chung Shan Medical and Dental College, Taichung, Taiwan, ROC.
authors.forename: L S
authors.initials: LS
authors.lastname: Chou
authors.forename: S M
authors.initials: SM
authors.lastname: Chao
authors.forename: S S
authors.initials: SS
authors.lastname: Bian
authors.forename: S H
authors.initials: SH
authors.lastname: Cherng
authors.forename: M Y
authors.initials: MY
authors.lastname: Chou
authors.forename: H
authors.initials: H
authors.lastname: Lee
mesh_terms: D000818:Animals; D016587:Antimutagenic Agents / Q000494:pharmacology*; D001345:Autoradiography; D001564:Benzo(a)pyrene / Q000494:pharmacology*; D018736:DNA Adducts / Q000187:drug effects*; D020366:Methylmethacrylate; D008768:Methylmethacrylates / Q000494:pharmacology*; D009153:Mutagens / Q000633:toxicity*; D011721:Pyrenes / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012486:Salmonella typhimurium
chemical_list: D016587:Antimutagenic Agents; D018736:DNA Adducts; D008768:Methylmethacrylates; D009153:Mutagens; D011721:Pyrenes; D020366:Methylmethacrylate; D001564:Benzo(a)pyrene; C032668:1-nitropyrene