Validation of the in vivo CD1 mouse splenocyte micronucleus test
Related Experiment Videos
V Benning1, D Brault, C Duvinage
1Rhône-Poulenc Rorer S.A., Centre de recherche de Vitry-Alfortville, Départment Sécurité du Médicament, Vitry sur Seine, France.
Abstract:
In order to validate the in vivo micronucleus test in mouse splenocytes using the cytokinesis block method, 14 compounds with various mechanisms of action were tested: three direct alkylating agents (mitomycin C, ethylnitrosourea, beta-propiolactone), seven indirect alkylating agents (cyclophosphamide, benzo[a]pyrene, diethylnitrosamine, dimethylnitrosamine, 4-aminophenol, 4-aminobiphenyl, 1,1-dimethylhydrazine), two intercalating agents (acridine orange, ethidium bromide) and two spindle poisons (vincristine, colchicine). Male mice were dosed once with the compound, and spleen samples were taken 2 or 14 days after treatment. A significant increase in the binucleated micronucleated splenocyte rate was observed with all the alkylating and intercalating agents at at least one sampling time. In contrast, no increase in the binucleated micronucleated splenocyte rate was observed with the spindle poisons. In conclusion, under these experimental conditions, this in vivo test seems appropriate for the detection of clastogenic compounds including compounds that cannot be detected in the bone marrow micronucleus test. The limit of this test, as expected, is the lack of detection of aneugenic compounds.
Insights
The in vivo micronucleus test in mouse splenocytes effectively detects clastogenic compounds, including those missed by bone marrow tests. However, it cannot identify aneugenic compounds.
Area of Science:
- Toxicology
- Genetics
- In vivo testing
Background:
- The in vivo micronucleus test is a crucial tool for assessing genotoxicity.
- Validating established methods ensures reliable data for regulatory purposes.
Purpose of the Study:
- To validate the in vivo micronucleus test in mouse splenocytes using the cytokinesis-block method.
- To evaluate the test's efficacy across various chemical classes with different mechanisms of action.
Main Methods:
- Tested 14 compounds (alkylating agents, intercalating agents, spindle poisons) in male mice.
- Administered single doses and collected spleen samples at 2 and 14 days post-treatment.
- Assessed the rate of binucleated micronucleated splenocytes.
Main Results:
- All tested alkylating and intercalating agents significantly increased micronucleated splenocyte rates.
- Spindle poisons did not induce a significant increase in micronucleated splenocytes.
- The test detected clastogenic compounds, including those negative in bone marrow tests.
Conclusions:
- The in vivo micronucleus test in mouse splenocytes is suitable for detecting clastogenic agents.
- The test's limitation is its inability to detect aneugenic compounds.
- This method offers an alternative for genotoxicity testing, particularly for compounds missed by other assays.