Related Experiment Videos
Long-term toxicity and carcinogenicity studies with 2,4/2,6-toluene-diisocyanate (80/20) in rats and mice
Abstract:
Groups of male and female rats and mice were exposed to 0.05 and 0.15 ppm of toluene-diisocyanate (TDI) by inhalation for 6 h/day, 5 days/week for approx. 2 years. Type and incidence of tumours and the number of tumour-bearing animals of either species did not indicate any carcinogenic effect. Haematology, biochemistry, urinalysis, and cytogenicity did not reveal any untoward effect. Increased mortality (females only), reduced weight gain and signs of irritation in the upper and lower respiratory tract resulted from exposure to TDI in the mouse study with the highest incidence in the 0.15 ppm exposure level. Male and female rats of the 0.15 ppm group gained less weight during the first 12 weeks of the study. Histopathological examination in the rat study has not been completed, but no effect in the respiratory tract or in any other tissue has yet been seen.
Insights
Long-term inhalation exposure to toluene-diisocyanate (TDI) did not show carcinogenic effects in rats and mice. However, TDI exposure caused increased mortality and respiratory irritation in mice.
Area of Science:
- Toxicology
- Inhalation Toxicology
- Chemical Safety
Background:
- Toluene-diisocyanate (TDI) is an industrial chemical used in polyurethane production.
- Understanding the long-term health effects of TDI exposure is crucial for occupational safety.
Purpose of the Study:
- To evaluate the potential carcinogenicity and other toxicological effects of chronic TDI inhalation in rodents.
Main Methods:
- Male and female rats and mice were exposed to TDI (0.05 and 0.15 ppm) via inhalation for 6 hours/day, 5 days/week, for approximately 2 years.
- Comprehensive assessments included tumor incidence, mortality, body weight, hematology, biochemistry, urinalysis, cytogenetics, and histopathology.
Main Results:
- No evidence of carcinogenic effects was observed in either species.
- Mice exhibited increased mortality (females only), reduced weight gain, and respiratory tract irritation, particularly at the 0.15 ppm level.
- Rats showed reduced weight gain in the 0.15 ppm group during the initial 12 weeks; histopathology was pending but showed no observed effects thus far.
Conclusions:
- Chronic TDI inhalation at the tested concentrations does not appear to be carcinogenic in rats and mice.
- TDI exposure can induce non-neoplastic effects, including respiratory irritation and altered mortality/morbidity, particularly in mice.