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[Mutagenicity studies of miporamicin]
1Toxicological Research Laboratories, Research Center, Toyo Jozo Co., Ltd.
Abstract:
Mutagenic activity of miporamicin (MPM), a new macrolide antibiotic for animal use, was examined using the reversion test with bacteria, the chromosomal aberration test with mammalian cells in culture and the micronucleus test with rodents. In the reversion test, MPM exhibited severe growth inhibition effect on the test bacteria but caused no increase of revertant colonies over the baseline levels, alone or in combination with S 9 mixture. In the chromosome aberration test, MPM induced a medium grade increase of chromosome aberrations at high concentrations, but induced no increase of polyploid cells over the control level. In the micronucleus test, MPM had no effect on induction of micronucleated polychromatic erythrocyte even at the 1/2 LD50 dose. From these results, we concluded that MPM has no effect on the induction of point mutations but has a weak clastogenicity which is detectable only by in vitro tests.
Insights
Miporamicin (MPM), an antibiotic for animals, showed no mutagenic activity in bacterial tests but a weak clastogenicity in mammalian cell tests. This macrolide antibiotic is unlikely to cause point mutations.
Area of Science:
- Pharmacology
- Toxicology
- Genetics
Context:
- Miporamicin (MPM) is a novel macrolide antibiotic developed for veterinary applications.
- Assessing the mutagenic potential of veterinary drugs is crucial for ensuring animal and public health safety.
- Standard genotoxicity assays are employed to evaluate the safety profile of new pharmaceutical compounds.
Purpose:
- To evaluate the mutagenic activity of miporamicin (MPM) using a battery of in vitro and in vivo genotoxicity tests.
- To determine if MPM induces gene mutations, chromosomal aberrations, or micronuclei formation.
- To establish the genotoxic risk profile of MPM for its intended use in animals.
Summary:
- The reversion test in bacteria showed significant growth inhibition by MPM but no increase in revertant colonies, indicating no mutagenicity.
- In vitro chromosomal aberration tests revealed a moderate increase in aberrations at high concentrations, suggesting weak clastogenicity.
- In vivo micronucleus tests in rodents did not show any induction of micronucleated polychromatic erythrocytes, even at sub-lethal doses.
- MPM demonstrated no effect on point mutation induction but exhibited weak in vitro clastogenicity.
Impact:
- The findings suggest that MPM has a low risk of inducing gene mutations.
- The weak clastogenicity observed in vitro requires careful consideration for risk assessment in veterinary use.
- This study provides essential genotoxicity data for the regulatory evaluation of miporamicin.