| 15550276 |
Bonfanti P, Colombo A, Orsi F, Nizzetto I, Andrioletti M, Bacchetta R, Mantecca P, Fascio U, Vailati G, Vismara C: Comparative teratogenicity of chlorpyrifos and malathion on Xenopus laevis development. Aquat Toxicol. 2004 Dec 10;70(3):189-200.
The embryotoxic potential of chlorpyrifos (CPF) and malathion (MTN), two organophosphorus insecticides (OPs), was evaluated by modified Frog Embryo Teratogenesis Assay-Xenopus (FETAX). CPF and MTN were not embryolethal even at the highest concentration tested (6000 microg/l), but both exhibited a powerful teratogenicity. The probit analysis of malformed larva percentages showed a TC (50) of 161.54mug/l for CPF, and a TC (50) of 2394.01 microg/l for MTN. Therefore, CPF teratogenicity was about 15 times higher than MTN. Larvae of both exposed groups were mainly affected by ventral and/or lateral tail flexure coupled with abnormal gut coiling. Histopathological diagnosis displayed abnormal myotomes and myocytes with marked hypertrophies localized at the cell extremity, probably due to a break away of myofibril extremities at the intersomitic junction level. We speculate that this muscular damage was related to inhibition of acetylcholinesterase that showed a clear concentration-response in CPF and MTN exposed larvae. The teratogenic effects of these anti-cholinesterase compounds on Xenopus laevis myogenesis suggest a possible role played by OPs on induction of congenital muscular dystrophy. |
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