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Micronuclei induction by dichlorvos in the mouse skin
1Toxicology Unit, National Institute of Occupational Health and Safety, Sydney, New South Wales, Australia.
Abstract:
Micronucleus (MN) induction in cultured keratinocytes was investigated following skin painting of HRA/Skh mice with the pesticide, dichlorvos. Whole skin and partially-purified epidermal cells from 5-6 week old male animals were cultured for 4 days in vitro after single topical applications of various concentrations of dichlorvos in vivo. Appropriate doses, allowing optimum survival of keratinocytes, were selected following an initial range-finding experiment. To evaluate MN induction in dividing cells, the cytokinesis-block method was employed. Results showed statistically significant MN at all dose levels in partially-purified epidermal cells and a positive trend with respect to dose from 51 to 1033 nmol dichlorvos. A significant increase in MN was also detectable in cultured cells from whole skin, dissociated within as little as 1 h after application of dichlorvos. Although a number of technical difficulties are associated with the skin micronucleus method, it has been used successfully in this laboratory to detect several skin carcinogens of both high and low potency. Since dichlorvos is rapidly absorbed through the skin, and can induce MN in skin cells of treated mice, this compound may therefore be considered to pose a contact hazard for exposed humans.
Insights
The pesticide dichlorvos induced micronuclei (MN), a marker of genetic damage, in mouse skin cells after topical application. This suggests dichlorvos poses a contact hazard to humans due to skin absorption and genotoxicity.
Area of Science:
- Toxicology
- Genetics
- Dermatology
Background:
- Pesticides can pose health risks through various exposure routes.
- Assessing genotoxicity of pesticides is crucial for understanding potential human health impacts.
- Dichlorvos is a widely used organophosphate pesticide.
Purpose of the Study:
- To investigate the potential of dichlorvos to induce micronucleus (MN) formation in mouse skin cells.
- To evaluate the genotoxic effects of dichlorvos following topical skin application.
- To assess the risk of dichlorvos as a contact hazard.
Main Methods:
- HRA/Skh mice were treated topically with varying concentrations of dichlorvos.
- Whole skin and partially-purified epidermal cells were cultured in vitro.
- The cytokinesis-block method was used to detect MN in dividing cells.
Main Results:
- Statistically significant MN induction was observed in epidermal cells at all tested dichlorvos doses.
- A dose-dependent increase in MN was noted.
- MN induction was detectable in whole skin cells shortly after dichlorvos application.
Conclusions:
- Dichlorvos is absorbed through the skin and induces genotoxic effects in skin cells.
- The findings suggest dichlorvos poses a contact hazard to humans.
- The skin micronucleus assay is a viable method for detecting skin carcinogens.