| First Author | Yoshida K | Year | 2006 |
| Journal | Exp Hematol | Volume | 34 |
| Issue | 3 | Pages | 274-83 |
| PubMed ID | 16543061 | Mgi Jnum | J:108470 |
| Mgi Id | MGI:3624143 | Doi | 10.1016/j.exphem.2005.11.016 |
| Citation | Yoshida K, et al. (2006) Caloric restriction prevents radiation-induced myeloid leukemia in C3H/HeMs mice and inversely increases incidence of tumor-free death: implications in changes in number of hemopoietic progenitor cells. Exp Hematol 34(3):274-83 |
| abstractText | OBJECTIVES: Previously, we found a clear decrease in the incidence of radiation-induced myeloid leukemia in C3H/HeMs mouse caused by caloric restriction (CalR). In this report, CalR before and after irradiation was examined to determine whether they exert different effects on the prevention of radiation-induced myeloid leukemogenesis and the consequent extension of life span by CalR. METHODS: The C3H/HeMS strain, which is prone to radiation-induced myeloid leukemia, was used. Groups subjected to different CalR timings, pre- and postirradiation, were compared with groups not subjected to CalR during their lifetime for the incidences of neoplasms, specifically that of myeloid leukemia, and the incidence of tumor-free death. A single dose of 3Gy X-ray was administered to mice at 10 weeks old. Results of colonization assay before and after CalR were compared with the incidence of leukemogenesis among the groups. RESULTS: Irrespective of the CalR timing in terms of irradiation, there was a significant difference in the prevention of myeloid leukemogenesis, and a consequent difference in longevity (731 approximately 805 days for CalR groups vs. 697 days for the group without CalR; Log rank, P<0.03). During CalR, the number of hemopoietic progenitor cells (HPCs), potential leukemogenic targets, significantly decreased (0.4 x 10(4) vs. 4.2 x 10(4) of granulomacrophage colony forming units per spleen; 1.3 x 10(4) vs. 7.6 x 10(4) of the splenic colony forming units per spleen), but this decreased number of HPCs returned to that of the non-CalR control group, when the CalR group was returned to nonrestricted diet (returned to 1.5 x 10(4) granulomacrophage colony-forming units per spleen; returned to 2.8 x 10(4) splenic colony-forming units per spleen). Although preirradiation CalR followed by a conventional non-CalR diet negates the potential preventive effect, prevention conferred by pre-and postirradiation CalR suggests different underlying mechanisms; preirradiation CalR prevents the initiation of direct genotoxic leukemogenesis, while postirradiation CalR the indirect, epigenetic, leukemogenesis. CONCLUSION: The incidences of tumor-free death significantly increased in all the groups undergoing CalR except for the group subjected to preirradiation CalR, which contributed to the longevity of the groups undergoing CalR. |
