#0156 Multiple organ cancers were caused by inhalation of 2-bromopropane in rats
Multiple organ cancers were caused by inhalation of 2-bromopropane in rats
2-Bromopropane (2-BP) is a colorless, non-flammable liquid. It serves as an intermediate in synthesizing medicines, agricultural chemicals, and photosensitizers. It also serves as a solvent with a high dermal absorption rate. Male and female workers in a Korean electronic factory, exposed to solvents containing 2-BP experienced reproductive and hematopoietic disorders. Studies have reported that 2-BP acts as a reproductive toxicant in rats and mice.
Furthermore, exposure to 2-BP has been found to induce DNA damage and impair functional antioxidant cellular defenses. Therefore, researchers must conduct carcinogenicity studies of 2-BP using experimental animals to assess the health risks for workers exposed to 2-BP. In this study, groups of 50 rats of both sexes (6 weeks old at the commencement) were exposed via whole-body inhalation to airflow containing 2-BP vapor at target concentrations of 0 (a control), 67, 200, and 600 ppm for 6 h/day and 5 days/week for 104 weeks.
Furthermore, the air/vapor mixture was cooled and condensed at 17°C before being diluted with clean air, vaporized, and introduced into chambers. Gas chromatography monitored 2-BP concentration every 15 min. Researchers observed rats daily for signs and mortality, measured weight and food consumption weekly, and performed necropsies at the study's end. Rats were euthanized under anesthesia, and organs were removed, weighed, and examined during terminal necropsy.
Inhalation of 2-BP at 600 ppm led to mortality by week 85. Survival rates decreased in groups exposed to 67 and 200 ppm. Tumor-related deaths occurred in the 600 ppm group from week 36 for females and week 41 for males, with survival rates dropping below 50% by week 53 for females and week 59 for males. Most deaths were tumor-related, with reduced food consumption observed in the 600 ppm group. A 2-year exposure induced significant tumors in multiple organs across all exposure concentrations.
The study indicates 2-BP's genotoxicity, causing DNA mutations in various organs, notably the large intestine. It stresses the importance of considering biological properties of genotoxic carcinogens in humans. Results suggest 2-BP as a potential human carcinogen, offering crucial data for risk assessment and exposure limit establishment.
Link to the original journal article:
https://academic.oup.com/joh/article/65/1/e12388/7479373
Title of the paper:
Multi-organ carcinogenicity by inhalation exposure to 2-Bromopropane in rats
Authors:
Hideki Senoh, Tatsuya Kasai, Shigeyuki Hirai, Yusuke Furukawa, Kyohei Misumi, Yuko Goto, Kenji Takanobu, Michiharu Matsumoto, Shoji Fukushima, Shigetoshi Aiso
