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Micronucleus test with ethyl methanesulfonate administered by intraperitoneal injection and oral gavage
Abstract:
The effect of route of administration on the outcome of the micronucleus test was studied by administering ethyl methanesulfonate (EMS) by oral gavage (p.o.) and intraperitoneal injection (i.p.) to males of 2 mouse strains, MS/Ae and CD-1. Based on preliminary studies, consisting of a small-scale acute toxicity test and a pilot experiment to determine the optimal sampling time and the appropriate dosages, a micronucleus test was conducted with a 24-h sampling time and doses of 50-400 mg/kg i.p. and p.o. EMS significantly induced micronucleated polychromatic erythrocytes (MNPCEs) with a clear positive dose response by both routes in both strains. Moreover, both routes showed almost the same induction rate of MNPCEs at each dose level tested in both strains.
Insights
Ethyl methanesulfonate (EMS) induced micronucleated polychromatic erythrocytes (MNPCEs) similarly via oral gavage and intraperitoneal injection in two mouse strains. Route of administration did not significantly alter the genotoxicity test outcomes.
Area of Science:
- Toxicology
- Genetics
- Pharmacology
Background:
- The micronucleus test is a standard assay for detecting genotoxicity.
- Understanding how administration routes affect test outcomes is crucial for accurate risk assessment.
- Ethyl methanesulfonate (EMS) is a known mutagen used as a positive control.
Purpose of the Study:
- To investigate the influence of administration route on the efficacy of the micronucleus test.
- To compare the induction of micronucleated polychromatic erythrocytes (MNPCEs) by EMS via oral gavage (p.o.) and intraperitoneal injection (i.p.).
Main Methods:
- Two mouse strains (MS/Ae and CD-1) were used.
- EMS was administered at doses ranging from 50-400 mg/kg via p.o. and i.p. routes.
- Micronucleus tests were conducted with a 24-hour sampling time.
Main Results:
- EMS significantly induced MNPCEs in both mouse strains via both administration routes.
- A clear positive dose-response relationship was observed for both p.o. and i.p. administration.
- The induction rates of MNPCEs were comparable between the oral and intraperitoneal routes at equivalent dose levels.
Conclusions:
- The route of administration (oral gavage vs. intraperitoneal injection) does not significantly impact the outcome of the micronucleus test for EMS.
- Both routes are effective in detecting EMS-induced genotoxicity, supporting their utility in toxicological studies.