US EPA

624921 

Journal Article 

Comparison of results from mouse bone marrow chromosome aberration and micronucleus tests 

Shelby, MD; Witt, KL 

1995 

Yes 

Environmental and Molecular Mutagenesis
ISSN: 0893-6692
EISSN: 1098-2280 

25 

4 

302-313 

English 

7607185 

10.1002/em.2850250407 

WOS:A1995RG03600006 

Tests for the induction of chromosomal aberrations (ABS) and micronuclei (MN) in bone marrow cells of mice have been conducted on 65 chemicals. Although these tests were not conducted with the purpose of comparing the outcomes of these two in vivo genetic toxicity endpoints, the availability of these test results permits such a comparison. Based on studies to date, results from the 2 tests agree for more than 80% of the chemicals; 17 gave positive results in both tests, and 36 gave negative results in both. Seven chemicals were positive only for ABS and 5 were positive only for MN. Three chemicals that were originally concluded to be positive for ABS but not for MN were found to induce MN when the MN protocol was modified to more closely reflect the ABS protocol. Among the 12 chemicals for which there are discrepant results, there are only 2 for which the difference is convincing. One of these, selenium sulfide (MN negative, ABS positive) remains an enigma; further studies are being conducted. The second, isoprene (MN positive, ABS negative) will be difficult to pursue because the studies reported here were done by inhalation exposure. Based on the outcomes of these comparisons, protocol factors, rather than endpoint specificity, appear to be the major source of discrepant test results. Thus, these results do not support a recommendation that both tests be conducted in a primary testing scheme for genetic toxicity. 

genetic toxicology; in vivo; cytogenetics