[Induction of micronucleus by organophosphorus pesticides both in vivo and in vitro].

A total of 22 organophosphorus pesticides (OPPs), including 8 ethyl-, 9 methyl-, and 5 other OPPs, were tested for mutagenicity in micronucleus assay system both in 615 mouse marrow cells in vivo with multi-intraperitoneal administrations and in cultured Chinese hamster lung (CHL) cells in vitro; and structure-mutagenicity relationship of OPPs was analyzed. Among the OPPs tested in vivo, 5 ethyl-(diazinon, chlorpyrifos, disulfoton, ethion, and parathion), and only 1 methyl-(dimethoate) were found mutagenic, while the other OPPs were negative. Six ethyl- (azinphos ethyl, chlorpyrifos, ethion, parathion, phosaione, and quinaphos), 8 methyl- (azinophos methyl, chlorpyrifos methyl, dichlorvos, dimethoate, fenitrothion, malathion, parathion methyl, and trimethyl phosphate), and 2 other OPPs (EII and MIA), however, induced micronucleus in CHL cells in vitro. The results indicated that most of the ethyl-OPPs tested showed the ability to induce micronucleus both in vivo and in vitro, and that most of the methyl-OPPs were positive only in vitro. The mechanism for the adversity of mutagenic activity in micronucleus assay in vivo and in vitro produced by different kinds of OPPs was also discussed.