The effects of single subcutaneous injection of cadmium chloride on haemopoiesis in normal (non- irradiated) or irradiated mice were investigated. Cadmium doses used ranged from 1-8 mg/kg body weight. Twenty-four hours after treatment with cadmium (doses from 3 to 8 mg/kg) there were no significant changes in bone marrow cellularity and the granulocyte-macrophage progenitor cell (GM- CFC) number per femur in non-irradiated female ICR mice. Similarly, during the 30-day postinjection period bone marrow cellularity and marrow GM-CFC number in mice treated with a cadmium dose of 5 mg/kg were not significantly different from the control values. Cadmium significantly reduced the lethal effects of gamma rays. In addition, increasing the doses of cadmium administered 24 h prior to sublethal irradiation increased the number of endogenous haemopoietic stem cells (endoCFU-S) in a concentration-dependent manner. Pretreatment with cadmium also decreased the radiation damage to endoCFU-S and haemopoietic progenitor cells committed to granulocyte/macrophage development (GM-CFC). The survival of stem cells was higher and the regeneration of cellularity and GM-CFC of irradiated bone marrow was accelerated in mice pretreated with 5 mg Cd/kg body weight in comparison with saline-injected mice.
The effect of administration of cadmium alone in non-irradiated mice as well as the effect of preirradiation administration of cadmium on the reparation processes of haemopoiesis were investigated in mice irradiated by a dose of 7.5 Gy. The pre-irradiation administration of cadmium accelerated the reparation processes in the bone marrow and spleen as well as the number of leukocytes and thrombocytes in the peripheral blood. The administration of cadmium alone caused a temporary weight decrease of the thymus and reduced number of erythrocytes, reticulocytes and haemoglobin values in the peripheral blood. The temporary rapid increase in the number of leukocytes on the 21st day after cadmium administration was investigated.
The effect of immunomodulatory agents on reparation processes in the thymus was studied in mice injured by a single sublethal or lethal dose of ionizing radiation ranging between 6.5-9.5 Gy. Reparation of thymus weight was not influenced by pretreatment with immunomodulators. Furthermore, the morphological picture did not exhibit appreciable differences between non-protected and protected groups, except for greater proliferation of fibroblasts and macrophages in protected animals.