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Published on: February 22, 2016
Respiratory irritative effects of trimethylbenzenes: an experimental animal study
Z Korsak1, K Rydzyński, J Jajte
1Department of Toxicity and Carcinogenesis, Nofer Institute of Occupational Medicine, Lódź, Poland.
Abstract:
Sensory respiratory irritation effects of trimethylbenzene isomers (TMBs) (hemimellitene, mesitylene and pseudocumene) in male Balb/C mice were investigated in conditions of acute exposure and in male Wistar rats in conditions of repeated 90-day inhalation exposure to pseudocumene. The pseudocumene, mesitylene and hemimellitene concentrations depressing the respiratory rate to 50% (RD50) were 578, 519, 541 ppm, respectively. Inhalation exposure to pseudocumene for 90 days increased the total number of cell macrophages, polymorphonuclear leukocytes and lymphocytes number at all three test concentrations compared with the controls. Total protein lactate dehydrogenase (LDH) and acid phosphatase activity in bronchoalveolar lavage (BAL) were significantly increased in all exposed groups. Based on the effects observed in the respiratory tract, the threshold limit value of at least 10 ppm should be considered for the occupational exposure to trimethylbenzene isomers.
Insights
Trimethylbenzene isomers cause respiratory irritation in mice and rats. Repeated exposure to pseudocumene led to increased immune cells and enzyme activity in the lungs, suggesting a 10 ppm occupational exposure limit.
Area of Science:
- Toxicology
- Environmental Health
- Occupational Safety
Background:
- Trimethylbenzene isomers (TMBs) are volatile organic compounds with potential health risks.
- Understanding the respiratory effects of TMBs is crucial for occupational safety.
- Previous research on TMBs' respiratory toxicity is limited.
Purpose of the Study:
- To investigate the sensory respiratory irritation effects of TMB isomers (hemimellitene, mesitylene, pseudocumene) in male Balb/C mice.
- To assess the effects of repeated 90-day inhalation exposure to pseudocumene in male Wistar rats.
- To determine a safe occupational exposure limit for TMB isomers.
Main Methods:
- Acute inhalation exposure in mice to determine RD50 concentrations for each TMB isomer.
- 90-day repeated inhalation exposure in rats to pseudocumene at various concentrations.
- Analysis of bronchoalveolar lavage (BAL) fluid for cell counts, total protein, lactate dehydrogenase (LDH), and acid phosphatase activity.
Main Results:
- RD50 values for pseudocumene, mesitylene, and hemimellitene were 578, 519, and 541 ppm, respectively.
- Repeated pseudocumene exposure increased macrophages, polymorphonuclear leukocytes, and lymphocytes in rat lungs.
- Elevated total protein, LDH, and acid phosphatase in BAL fluid of exposed rats indicated lung inflammation and damage.
Conclusions:
- TMB isomers cause significant respiratory irritation and inflammatory responses.
- Repeated exposure to pseudocumene induces cellular and biochemical changes in the respiratory tract.
- A threshold limit value of at least 10 ppm is recommended for occupational exposure to TMB isomers.
