RESUMEN
This study aimed to investigate if zinc compound would have effects on body weight loss and bone marrow suppression induced by total body irradiation (TBI). ICR mice were divided randomly into two groups and treated with test or control compounds. The test compound contained zinc (amino acid chelated with bovine prostate extract), and the control was reverse osmosis pure water (RO water). One week after receiving the treatment, mice were unirradiated, or irradiated with 6 or 3 Gy by 6 MV photon beams to the total body. Body weight changes were examined at regular intervals. Three and 5 weeks after the radiation, animals were sacrificed to examine the histologic changes in the bone marrow. Lower body weight in the period of 1-5 weeks after radiation and poor survival rate were found after the 6 Gy TBI, as compared with the 3 Gy groups. The median survival time after 6 Gy and 3 Gy TBI for mice given the test compound were 26 and 76 days, respectively, and the corresponding figures were 14 and 70 days, respectively, for mice given the control compound (p < 0.00001). With zinc supplement, the mean body weight in mice which received the same dose of radiation was 7-8 g heavier than in the water-supplement groups during the second and third weeks (p < 0.05). Hence, there was no statistically significant difference in survival rate between zinc and water supplement in mice given the same dose of irradiation. Histopathologically, there was less recovery of bone marrow cells in the 6 Gy groups compared with the 3 Gy groups. In the 3 Gy water-supplement group, the nucleated cells and megakaryocytes were recovered in the fifth week when recovery was still not seen in the 6 Gy group. With zinc supplement, these cells were recovered in the third week. In this study, we found that zinc is beneficial to body weight in mice treated with TBI. Histologic examination of bone marrow showed better recovery of bone marrow cells in groups of mice fed with zinc. This study suggests that zinc can be used as supplements in cancer patients receiving radiotherapy to reduce radiation-induced complications.