title: p53 dependency of radio-adaptive responses in endogenous spleen colonies and peripheral blood-cell counts in C57BL mice.
abstract: Radio-adaptive responses at a conditioning X-ray dose of 0.45 Gy and a challenging dose of 5.0 Gy on hematopoietic indices were studied in C57BL mice with p53 (Trp53) wild, heterogenous and knockout allele. The conditioning irradiation, given 2 weeks before the challenging irradiation, induced radio-adaptive responses observed as a recovery of the peripheral blood-cell counts of leukocytes, thrombocytes and erythrocytes on day 14 after challenging irradiation in C57BL mice of the wild-type p53(+/+). The pre-irradiation also increased the endogenous spleen colonies (endo-CFU-S) on day 12 and the spleen weight on day 14. On the contrary, the knockout p53(-/-) mice gave no such radio-adaptive response. The heterogenous p53(+/-) mice gave an intermediate response. The radio-adaptive response in hematopoiesis at a challenge dose of 5.0 Gy seems to be a p53-dependent phenomenon. The possible role of induction in radio-resistance through the reduction of p53-drived apoptosis in hematopoietic stem cells in pre-irradiated mice is discussed.
authors.affiliation: Laboratory of Veterinary Radiology, Division of Veterinary Science, Graduate School of Agriculture and Biological Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan.
authors.forename: Kiyohito
authors.initials: K
authors.lastname: Horie
authors.forename: Kihei
authors.initials: K
authors.lastname: Kubo
authors.forename: Morio
authors.initials: M
authors.lastname: Yonezawa
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000528:radiation effects; D001772:Blood Cell Count; D003114:Colony-Forming Units Assay; D004307:Dose-Response Relationship, Radiation; D006410:Hematopoiesis / Q000528:radiation effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D009929:Organ Size / Q000528:radiation effects; D011836:Radiation Tolerance / Q000235:genetics / Q000502:physiology*; D013154:Spleen / Q000473:pathology / Q000528:radiation effects; D016159:Tumor Suppressor Protein p53 / Q000502:physiology*
chemical_list: D016159:Tumor Suppressor Protein p53