Induction of chromosome aberrations and micronuclei in pulmonary alveolar macrophages of rats following inhalation of mosquito coil smoke.

The genotoxic potential of inhalation of mosquito coil (MC) smoke was evaluated by using metaphase chromosome aberration and micronucleus assays in pulmonary alveolar macrophages (PAMs) of rats following short-term as well as long-term whole body intermittent exposure. For short-term exposure, the animals were exposed for 15 min/h, 8 h/day to smoke collected for 1, 5 or 10 min, and they were killed 16 or 24 h after the final exposure. For long-term exposure, they were exposed for 15 min/h, 8 h/day, 7 days/week to smoke collected for 10 min and then they were killed 24 h after the final exposure. Each time before exposure, fresh smoke was collected by burning a mosquito coil. Pulmonary lavage was collected, and conventional flame-drying preparation was done for metaphase chromosome analysis and micronuclei (MN) were analyzed from smear preparations. Significantly higher frequencies of chromosome aberrations, including as well as excluding gaps, and micronucleated PAMs in smoke-exposed animals, compared to controls, indicated genotoxic capacity of MC smoke. The increases significantly correlated with the "concentration" of the gas. Mitotic indices also showed a significant and concentration-dependent increase. The frequencies of chromosome aberrations and MN following 7-day exposure were very similar to those for 1-day exposure. This was probably due to the transient nature of PAMs. A post-exposure gap of 24 h, compared to the 16-h gap, yielded a higher incidence of both mitoses and chromosome aberrations.