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Assessment of methyl methacrylate genotoxicity by the micronucleus test
Amarildo Mariano de Araújo1, Guilherme Rodrigues Alves, Guilherme Trevisan Avanço
1Univ do Oeste Paulista, SP, Brazil.
Abstract:
The aim of this study was to evaluate the genotoxic potential of methyl methacrylate (MMA) vapor by simulating standard occupational exposure of 8 hours per day and using the micronucleus test. We used 32 adult male Wistar rats divided into three groups: A - 16 rats exposed to MMA for 8 hours a day, B - Eight rats receiving single subcutaneous doses of cyclophosphamide on the first day of the experiment (positive control), C - Eight rats receiving only water and food ad libitum (negative control). Eight rats from group A and all of the rats from groups B and C were sacrificed 24 hours after beginning the experiment (acute exposure in group A). The remaining animals in group A were sacrificed 5 days after the experiment began (repeated exposure assessment in group A, simulating occupational exposure 40 hours/week). Femoral bone marrow was collected from each rat at the time of sacrifice for use in the micronucleus test. Two slides were completed per animal and were stained with Giemsa staining. Two thousand polychromatic erythrocytes were counted per animal. The Kruskal-Wallis test followed by a multiple comparisons test (Dunn test) was used for statistical analysis. The median number of micronuclei was 7.00 in the group exposed to MMA for 1 day, 2.00 in the group exposed to MMA for 5 days, 9.00 in the group exposed to cyclophosphamide (positive control) and 0.756 in the negative control group (p < 0.0001). MMA was genotoxic when measured after 1 day of exposure but was not evidently genotoxic after 5 days.
Insights
Methyl methacrylate (MMA) vapor showed genotoxic potential after one day of occupational exposure simulation. However, repeated exposure over five days did not reveal significant genotoxicity in Wistar rats.
Area of Science:
- Toxicology
- Genetics
- Occupational Health
Background:
- Methyl methacrylate (MMA) is widely used in industries, necessitating evaluation of its occupational health risks.
- Understanding the genotoxic potential of MMA vapor is crucial for worker safety.
- Previous studies on MMA genotoxicity have yielded varied results, warranting further investigation.
Purpose of the Study:
- To assess the genotoxic effects of methyl methacrylate (MMA) vapor.
- To simulate standard occupational exposure conditions (8 hours/day, 40 hours/week).
- To evaluate genotoxicity using the micronucleus test in Wistar rats.
Main Methods:
- 32 male Wistar rats were divided into three groups: MMA exposure, cyclophosphamide (positive control), and negative control.
- Acute (24 hours) and repeated (5 days) MMA vapor exposure was administered.
- Femoral bone marrow was analyzed using the micronucleus test.
- Statistical analysis was performed using the Kruskal-Wallis and Dunn tests.
Main Results:
- A significant increase in micronuclei was observed after 1 day of MMA exposure (median 7.00) compared to the negative control (median 0.756).
- After 5 days of MMA exposure, the median number of micronuclei decreased to 2.00, indicating reduced genotoxicity.
- The positive control group (cyclophosphamide) showed a high median of 9.00 micronuclei.
Conclusions:
- Methyl methacrylate vapor exhibits genotoxic potential following acute occupational exposure.
- Repeated or prolonged occupational exposure to MMA vapor may not result in evident genotoxicity.
- Further research is needed to fully elucidate the long-term genotoxic effects of MMA.
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