Effect of temperature on the frequency of chromosome aberrations and micronuclei in cultured Chinese hamster cells

We previously reported that both hyperthermia and hypothermia induced micronuclei in mouse bone marrow cells (Asanami and Shimono, 1997a, 1997b, 1999). To investigate the effects of temperature on chromosome aberration in vitro, we conducted chromosome aberration and micronucleus tests under hyper- and hypothermic conditions using Chinese hamster lung (CHL) cells. In the chromosome aberration test, we observed positive responses at 40 degrees C and 41 degrees C for 24 hr, and at 42 degrees C for 6 hr and over. In the micronucleus test, we observed positive responses at 31 degrees C, 33 degrees C, and 40 degrees C for 24 hr, and at 42 degrees C for 2 hr. The results suggest that in CHL cells, hypothermic conditions can induce micronuclei while hyperthermic conditions can induce both chromosome aberrations and micronuclei.