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Mutagenicity studies with 2,4,5-T on bacteria and mammalian germ cells
Abstract:
The herbicide 2,4,5-T (2,4,5-trichlorophenoxyacetic acid) was evaluated for potential mutagenicity by a Salmonella/mammalian-microsome test, a dominant lethal test on female rats, and by a cytogenetic assay on spermatogonia of Chinese hamster. In the Salmonella/mammalian-microsome test on four Salmonella typhimurium strains (TA 1535, TA 100, TA 1537, and TA 98), doses of up to and including 2500 micrograms/plate did not cause any mutagenic effects. In a dominant lethal test on female rats, 8-week dietary administration of 2,4,5-T at doses of up to and including 10 mg/kg/day did not cause any increase in preimplantation loss or the rate of dead implants, and did not have any effect on the fertilization quota. Cytogenetic analysis of the spermatogonia of male Chinese hamsters orally dosed five times at 24-hr intervals with 2,4,5-T at levels of up to and including 100 mg/kg did not provide any indication of 2,4,5-T having chromosome-damaging effects. Therefore, none of the three test systems provided any indication of 2,4,5-T having a mutagenic effect.
Insights
This study assessed the mutagenicity of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) using bacterial, rat, and hamster models. Results from all three tests indicated no mutagenic or chromosome-damaging effects from 2,4,5-T exposure.
Area of Science:
- Environmental toxicology
- Genetics and heredity
- Chemical safety assessment
Background:
- The herbicide 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) has been subject to scrutiny regarding its potential health impacts.
- Understanding the mutagenic potential of widely used agricultural chemicals is crucial for public health and environmental safety.
Purpose of the Study:
- To comprehensively evaluate the mutagenicity of 2,4,5-T using a battery of established toxicological assays.
- To determine if 2,4,5-T induces genetic mutations or chromosomal damage in relevant biological systems.
Main Methods:
- Salmonella/mammalian-microsome assay (Ames test) was performed on four Salmonella typhimurium strains.
- A dominant lethal test was conducted on female rats following 8-week dietary administration of 2,4,5-T.
- Cytogenetic analysis of spermatogonia was carried out on male Chinese hamsters exposed to 2,4,5-T.
Main Results:
- The Salmonella/mammalian-microsome test showed no mutagenic effects across tested strains, even at high doses (up to 2500 µg/plate).
- The dominant lethal test in rats revealed no significant increase in preimplantation loss, dead implants, or altered fertilization rates with 2,4,5-T exposure (up to 10 mg/kg/day).
- Cytogenetic assays in Chinese hamsters did not indicate any chromosome-damaging effects of 2,4,5-T (up to 100 mg/kg).
Conclusions:
- Across three distinct test systems, 2,4,5-T demonstrated no evidence of mutagenicity.
- The findings suggest that 2,4,5-T does not pose a significant mutagenic risk based on these in vitro and in vivo evaluations.
- This comprehensive toxicological assessment provides data on the genotoxic profile of 2,4,5-T.