title: High body temperature induces micronuclei in mouse bone marrow.
abstract: The mouse micronucleus test was conducted to investigate the effect of high body temperature on micronucleus induction. Group of 10 male ddY mice were exposed to 30 degrees C for 1, 3 or 6 h, 37 degrees C for 0.5, 1, 2, 3 or 4 h, and 40 degrees C for 1 or 2 h. Bone marrow cells were sampled 24 h after heat exposure. Exposure of mice to 37 degrees C for 3 or 4 h and 40 degrees C for 1 or 2 h raised body temperature to approximately 40.5 degrees C and produced statistically significant increases in micronucleated polychromatic erythrocyte frequencies (8.1 +/- 4.5, 6.0 +/- 2.1, 5.3 +/- 3.3, 7.5 +/- 2.9%, respectively; control frequencies, 2.0 +/- 1.1%). In addition, about 25% of the induced micronuclei were relatively large (diameter of micronucleus > or = 1/4 diameter of cytoplasm). These results suggest that body temperatures of 39.5 degrees C or higher for more than 30 min induce micronuclei in bone marrow cells, and one possible mechanism is disturbance of the mitotic apparatus.
authors.affiliation: Naruto Research Institute, Otsuka Pharmaceutical Factory, Inc., Tokushima, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Asanami
authors.forename: K
authors.initials: K
authors.lastname: Shimono
mesh_terms: D000818:Animals; D001831:Body Temperature / Q000502:physiology*; D001853:Bone Marrow / Q000187:drug effects* / Q000502:physiology; D002467:Cell Nucleus / Q000187:drug effects / Q000502:physiology*; D003078:Colchicine / Q000633:toxicity; D006358:Hot Temperature; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D015162:Micronucleus Tests; D016685:Mitomycin / Q000633:toxicity; D009153:Mutagens / Q000633:toxicity; D012007:Rectum / Q000502:physiology; D013997:Time Factors
chemical_list: D009153:Mutagens; D016685:Mitomycin; D003078:Colchicine