Low-Dose Radiation Induced Proteins And Their Effects On Lymphocytes

By the late 1970s, studies on radiation effect have attended to low dose radiation(LDR).Many investigators have reported that very low doses of ionizing radiation could enhance growth and fecundity, down-regulate tumour incidence and extend life span. It is now certain that low-dose radiation can induce adaptive response and stimulative effects on both mammalian cells and mammals as whole. But the molecular mechanisms of adaptation and stimulative effects are not fully understood. To find the substantial basis for stimulative effects of low dose radiation, and to determine the capacity of low doses of radiation to induce adaptive proteines, LDR induced proteins are extracted and the effects on lymphocytes of mouse and human were observed. In this study the effects of LDR on lymphocyte subsets were also studied.Objective: 1. Low dose radiation induced proteins were extracted and their biological activity was detected 2. Stimulative effects of LDR on mouse spleen cells and human peripheral lymphocytes were determined 3. Stimulative effects of LDR on human peripheral blood lymphocyte subsets were studied 4. Stimulative effects of LDR on NK(CD57)cells and No-NK cells in human peripheral blood were investigated 5. Stimulative effect of LDR on expression of CD25 molecule of lymphocytes was observed.Methods: 1. Healthy Kumning male mice were irradiated with 5, 10, 15cGy 226Ra r-rays respectively. The mice were killed 2 hours after exposure, the spleen cells were broken with ultrasonic energy and then ultracentrifugalized at lowtemperature(4) . The supernatant solution contained with LDR induced proteins. The proteins at various content were then applied to stimulate the transformation of mouse spleen cells in vitro. DPM was used as index ( 3H~TdR was incorporated in DNA)and the activity of LDR induced proteins was observed and compared at different time and doses. The solution which contained with LDR induced proteins was filtered by sephadex G-100 gel. Subsequently newly emerging proteins were detected and their molecular weight were determined by SDS-poly aery 1 amide gel electrophoresis. The contents of newly emerging proteins were determined by Lowry' s method. 2. LDR induced proteins were used to stimulate mice spleen cells and human peripheral blood lymphocytes (the cells were incorporated by MOTdR or 3H-TdR). In culture medium with PHA or LPS respectively, CPM or DPM value was used as index. The stimulative effects of LDR proteins on mice spleen cells and T lymphocytes or B lymphocytes in human peripheral blood were studied. 3. Three kinds of McAb(antiCD4, CDS, CD19 cells) were used to separate CD4, CDS and CD19 cells from human peripheral blood by Panning direct method and the cells were incorporated by 3H-TdR. LDR induced proteins were used to stimulate human peripheral blood lymphocyte subsets in culture medium with PHA or LPS respectively. 4. McAb(anti CD57 cells) was used to separate CD57 cells from human peripheral blood by Panning direct method. The CD57 cells and non~CD57 cells were used as an effective cells. K562 cells labeled by 3H~TDR were used as target cells. The ratio of effect: target was lOrl.NK activity of CD57 cells or non~CD57 cells with LDR induced protein was used to express the efficiency of anti tumor cells. 5 LDR induced proteins were used to stimulatehuman peripheral blood lymphocytes for 24 hours. Then the changes of CD25 molecule were measured by flow cytometry (FCM) with immunofluorescence technique. Which was used to reflect the effect of LDR induced proteins on CD25 molecule expression of human lymphocytes.Results: As 3HTdR was incorporated in spleen cells of mouse,the DPM value increased significantly with the stimulation of the medium contained LDR induced proteins. When irradiation dose at 5,10,15cGy the values increased by 125. 28 % , 163 . 43 % and 169. 83 % compared with control groups respectively. The DPM value reached the highest point at lOcGy. Newly emerging proteins had been observed in this experiment , The molecular weight of the proteins wa...