Mechanisms towards compensation of long-term haemopoietic injury in mice after 5 Gy irradiation: in vivo and in vitro enhancement of superoxide anion production by granulocytes

Radioprotective effects of ocimum flavonoids on leukocyte oxidants and antioxidants in oral cancer

Oxidants (NADPH oxidase and myeloperoxidase) and antioxidants (GSH,GSH peroxidase, SOD and glucose 6 phosphate dehydrogenase, that provides NADPH for antioxidants) were assayed in the neutrophils from oral cancer patients, in three stages viz, baseline samples,15 days after radiation and 30 days following radiation. These samples were obtained from 2 groups of patients. Group A that received radiation alone and Group B that received radiation and ocimum flavonoids,a radioprotector. The results showed a significant fall in the SOD levels in the second follow up of group B.Glucose 6 phosphate dehydrogenase showed significant increase only in the first follow up of patients who received Ocimum flavonoids. Except for these findings all other parameters remained statistically nonsignificant.

Long-term haemopoietic injury in mouse by 1 Gy X-rays at different postconceptional stages

Haemopoietic effects in mice produced by a single acute dose of 1 Gy X-rays given on the 4th (4R) and 13th (13R) day postconception were evaluated throughout the 9-month post-irradiation. The quality of the stroma was measured in long-term bone marrow cultures (LTBMC). LTBMC granulocyte production was always markedly lower among the irradiated offspring than among controls. IL-6 supernatant levels were significantly higher in both experimental models with respect to controls. However, supernatants from 13R mice had a greater colony-stimulating activity than 4R mice and controls. Granulocytes, from culture or peripheral blood, did not show changes in their functional activity after either treatment. With regard to the content of the femoral granulocyte-macrophage colony forming cells (GM-CFC), there was an enhancement of the GM-colony number as determined from the marrow of 13R mice. In these mice, an alteration in colony size and number due to different combinations of colony-stimulating factors was observed. In summary, our results obtained with irradiation during the foetal period suggest that this 1 Gy X-rays is sufficient to produce measurable, effects on developing murine haemopoiesis.

Residual haematopoietic damage in adult and 8 day-old mice exposed to 7 Gy of X-rays

Our experiments have focused on the analysis of residual haematopoietic damage in 8-day-old and 12-week-old mice X-irradiated with a single dose of 7 Gy. In the case of the adult mice, analysis of the femoral and splenic CFU-S, CFU-GM and BFU-E showed a persistent depletion of these haematopoietic progenitor cells after irradiation. In contrast, in 1-week-old irradiated mice, a progressive recovery of the femoral haematopoietic progenitors was observed, achieving essentially normal values 1 year after irradiation. The spleens of these mice, however, contained significantly less haematopoietic progenitors than the control group, mainly as a consequence of the size reduction of this organ. In the peripheral blood, normal cellularity values were observed in most cases, although in the adult group a decline in numbers or circulating cells was noted after the first year following irradiation. Long-term bone marrow cultures (LTBMCs) established 1 year after the irradiation of adult mice generated poor adherent layers, while confluent stromas were observed in flasks corresponding to 8-day-old irradiated mice. Analyses of the functional activity of granulocytes obtained from either the peripheral blood or LTBMCs revealed that both young and adult irradiated mice produced granulocytes generating high levels of superoxide anion, in relation to age-matched controls. This finding was correlated with a long-term microenvironmental activation which resulted in an overproduction of granulocyte-macrophage colony-stimulating factor.