The mutagenic potential of hyperthermia and fever in mice

The cytogenetic effects of hyperthermia resulting from climatic influences as well as from infections were studied. Whole-body exposure of NMRI mice to an elevated environmental temperature induced a high frequency of micronucleated polychromatic erythrocytes in bone marrow. Hyperthermia at high relative humidity was more effective in increasing body temperature and cytogenetic damage than at low RH. A sex-related difference in response to heat stress was observed. Hyperthermia on pregnant mice induced a significant increase in the incidence of micronucleated PEs in fetal blood cells. Parenteral administration of bacterial endotoxin, lipopolysaccharides, induced either hypothermia or hyperthermia. However, LPS-induced hypothermia as well as fever does not so far appear to produce cytogenetic damage.