1-Bromopropane (1-BP; n-propyl bromide) (CAS No. 106-94-5) is an alternative to ozone-depleting chlorofluorocarbons that has a variety of potential applications as a cleaning agent for metals and electronics, and as a solvent vehicle for spray adhesives. Its analogue, 2-brompropane (2-BP; isopropyl bromide) (CAS No. 75-26-3) impairs antioxidant cellular defenses, enhances lipid peroxidation, and causes DNA damage in vitro. In the present study, DNA damage was assessed in human leukocytes exposed in vitro to 1-BP or 2-BP at 0, 0.01, 0.1, or 1 mM for 8 hr; or at 1 mM for 1, 2, 4 or 8 hr. Exposures to 1-BP or 2-BP were performed in triplicate samples of fresh heparinized venous blood from an adult male volunteer. For estimation of DNA damage, comets were produced by alkaline microgel-electrophoresis. In each sample, DNA damage was estimated in a minimum of 100 leukocytes using VisComet image analysis software. Apoptosis was assessed in leukocytes exposed to 1-BP or 2-BP using the DNA diffusion assay. 1-BP or 2-BP induced a significant increase in comet tail moment at 1 mM but not at 0.01 or 0.1 mM. DNA strand break number was significantly increased at 0.1 and 1 mM of 1-BP or 2-BP. In temporal studies, a significant increase in DNA damage was evident 1, 2, 4, or 8 hrs after exposure to 2-BP, whereas increased DNA damage was observed only after 4 or 8 hrs of exposure to 1-BP. Significant increases in apoptosis were evident after exposure to 0.1 or 1 mM 2-BP, but only after exposure to 1 mM 1-BP. Results demonstrate the potential for 1-BP and 2-BP to induce DNA damage in vitro in human leukocytes.
The Toxicologist. Society of Toxicology 43nd Annual Meeting and ToxExpo, March 21-25, 2004, Baltimore, Maryland