Study Of The Hormesis Of Low Dose Radiation On Cord Blood And Their Medical Meanings

[Objective] l.To explore the hormesis on T lymphocytes in umbilical cord blood (UCB) induced by low dose radiation (LDR). 2.To determine the optimal stimulatory dose. 3.To study the hormesis on the expression of IL-2, IL-8, EPO and SOD-1 in UCB induced by LDR. 4. To detect, compare and analyse the soluble IL-2, IL-8, EPO and SOD-1 production by UCB, pared pregnant women and adult peripheral blood with their medical meanings. 5.To estimate the activated UCB induced by LDR with its medical meanings. 6.To investigate the possible biological features of IL-2, IL-8, EPO and SOD-1 in UCB. 7.To establish a LDR model.[Methods] 0.1 ml/0.3ml UCB in RPMI 1640 2ml were irradiated by 0, 2.5, 5, 10 and 20cGy 226Ra r-rays respectively . The syntheses of DNA were detected by incorporation of 3H-TdR in T lymphocytes after LDR, also the syntheses of RNA and protein were detected by double labeled incorporation of both 14C-UR and 3H-Tyr in T lymphocytes after LDR. Levels of IL-2, IL-8, EPO and SOD-1 in CB plasma (CBp) after LDR and serum were assayed by radioimmune assay(RIA).[Results] l.The CPM(count per minute) of T lymphocytes with 3H-TdR incorporation in UCB were increased by 122.1%, 139.0%, 129.8% and 126.4% respectively compared with control group (0 cGy group) after 2.5cGy, 5cGy, 10cGy and 20cGy LDR stimulation respectively. Of which, the 5cGy group was increased the most and was significant difference compared with OcGy group (P<0.05).2. The DPM (decay per minute) of T lymphocytes with both 14C-UR and 3H-Tyr incorporation in UCB were increased by 121.3% and 149.3% respectively compared with 0cGy group after 5cGy LDR stimulation and there were significant and very significant difference respectively compared with control group (P <0.05 and <0.01). 3. The levels of IL-2, IL-8, EPO and SOD-1 were up-regulated 1 hr late after 5cGy stimulation and there were all significant difference compared with 0cGy group (P<0.05), of which , EPO was very significant difference (P <0.01). Ef (Effective fraction) were 0.48, 0.54, 0.49 and 0.39 respectively. 4. Being detected by RIA show that : (1) EPO levels of CBs (cord blood serum) and pPBs (pared pregnant women peripheral blood serum) were significantly higher than that of nPBs (normal adult peripheral blood serum) P<0.01, however, CBs compared with pPBs were no significant difference (P>0.05). (2) SOD-1 levels of CBs were significantly higher than that of both pPBs and nPBs (P<0.01), there were no significant difference between pPBs and nPBs (P>0.05). (3) IL-2 levels were no significant difference among CBs, pPBs and nPBs (P>0.05), but the level of CBs was 1.78ng/ml0.05), but the level of CBs was 0.13ng/ml