Radiotoxicity to bone marrow after 89Sr therapy sensitized by nicotinamide and carbogen in mice

To investigate the radiotoxicity to bone marrow in mice after 89Sr therapy sensitized by nicotinamide and carbogen in mice, the mice were divided into 5 groups: negative control (saline), positive control (89Sr), 89Sr + nicotinamide, 89Sr + Carbogen and 89Sr + nicotinamide + carbogen. 89SrCl was intravenously injected as a bolus containing activities of 7400 kBq/200 μL and saline was administrated in equal volume in the negative control group. 1, 2, 3, 4, 6, 8, 15, 20, 30, 60 and 90 days after injection the mice were killed for micronuclei assay in femoral marrow polychromatic erythrocytes (PCE). The average frequency of polychromatic erythrocytes micronuclei (MnPCEs) showed a dual peak. The first maximum MnPCEs frequency occurred between the 2nd and the 4th day, and the second between the 10th and the 14th day. A significant statistic difference on the MnPCEs frequency was found between the negative and the positive control group (P<0.01, F=15.517), while no difference was found (P>0.05) among 89Sr + N + C, 89Sr, 89Sr + N and 89Sr + C. There is also no significant difference on MnPCEs frequency among Chinese Kunming Mice, NIH mice, BALB/c and F1 mice (P>0.05). Although the intervention of radio-sensitizer accelerated the occurrence of micronuclei in PCE, there was no significant statistical difference between the groups with or without radio-sensitizer. The administration of ratio-sensitizer did not aggravate the toxicity on marrow. (authors)