Hyperthermia-induced micronucleus formation in a human keratinocyte cell line

Elevated temperature can cause biological effects in vitro and in vivo. Many studies on effects of hypo-and hyperthermia have been conducted, but only few studies systematically investigated the formation of genomic damage in the micronucleus test in human cells in vitro as a consequence of different temperatures. In the present study, HaCaT human keratinocytes were exposed to different temperatures from 37 degrees C to 42 degrees C for 24 h in a regular cell culture incubator. Micronucleus frequency as a marker of genomic damage was elevated in a temperature-dependent and statistically significant manner. Apoptosis occurred at temperatures of 39 degrees C or higher. Cell proliferation was unaffected up to 40 degrees C and decreased at 41 degrees C and 42 degrees C. Expression of the heat shock protein Hsp70 was elevatec, particularly at temperatures of 40 degrees C and higher. These findings are in agreement with several in vivo studies and some in vitro studies looking at single, specific temperatures, but a systematically investigated temperature-dependent increase of genomic damage in human keratinocytes in vitro is demonstrated for the first time here: (C) 2012 Elsevier B.V. All rights reserved.