Studies Of The Radiobiological Effect On STBI And FTBI

PartⅠThe study of the survival rate of leukemic cell in vitro culture of different time-dose-fraction irradiation.Objective: To investigate the effect to survival rate of leukemic cell K562 and S-801 in different time-dose-fraction irradiation.Methods: Leukemic cell K562 and S-801 were cultivated in vitro. Fiting the survival curve by RADIO-MED software through semisolid culture medium colony formation experiment and obtaining the coherent parameter: D0,Dq,N . The SLDR capability was analyzed through the parameter: Dq. The survival rate of leukemic cell in vitro culture was observed in different time-dose-fraction irradiation(8Gy vs 4Gy×2;12Gy vs 2Gy×2×3).Results: 1.The survival curve of leukemic cell K562 and S-801 manifest that the shoulder was very narrow, the Dq value of K562 and S-801 was 0.39 and 0.28 . There was no significant difference in the survival rate in different time-dose-fraction irradiation (P>0.05).Conclusion: The SLDR capability of leukemic cell was little. There was no significant difference in radiobiological effect of different time-dose-fraction irradiation on leukemic cells.PartⅡInvestigation of elimination of T leukomonocyte( CD4+Th,CD8+CTL) and radiation injury of normal tissue of Sprague-Dawley rats in different time- dose-fraction irradiation.Objective: To investigate the different effect on elimination of the T leukomonocyte (CD4+Th,CD8+CTL) and radiation injury of normal tissue of Sprague-Dawley rats in different time-dose-fraction irradiation. Methods: 45 maturity Sprague-Dawley rats were randomly divided into 5 groups : blank control group, STBI 8Gy group, FTBI 4Gy×2 group, STBI 12Gy group, FTBI 2Gy×2×3 group. The TBI group rats were irradiated by 6MV X ray of electric linear accelerator using a 10cGy/min dose rate. Drawing venous blood from caudal vein on the third day and seventh day after TBI to observe the diversity of WBC,RBC,HB,PLT in peripheral blood; The diversity of CD4+Th,CD8+CTL and the sum total of T leukomonocyte was detected by flow cytometer (FCM); Immunohistochemical method was used to detect the expression of TGF-β1 protein in lung on the first day and fourteenth day after TBI and analyze the radiation-induced lung injury of different time-dose-fraction radiation. Viewing the allocation of TGF-β1 protein in lung by laser–scanning confocal microscope ; ALT and BUN was detected to analyze the hepatic function and renal function of rats after TBI. To observe the pathohistology of radiation injury of liver and kidney by HE stain.Results: 1. RBC and HB have no significant degression after TBI while the WBC and PLT manifest dose-dependent degression, and the WBC descended obviously in them. 2. CD4+Th,CD8+CTL and the sum total of T leukomonocyte manifest dose-dependent degression and have no obvious relation with fraction irradiation in identical dose. 3. Immunohistochemical expression level of TGF-β1 protein on the first day and fourteenth day after TBI showed significant difference in STBI and FTBI and expression level of TGF-β1 protein was low in FTBI compare to STBI in identical irradiation dose except 8Gy group and 4Gy×2 group on the first day. 4. ALT an BUN have no significant diversity compare to blank control group,pathohistology of irradiation injury of liver and kidney were not obvious.Conclusion: Total dose can be increased in proper extent through adopting FTBI pattern, then we can improve elimination of leukemic cell and T leukomonocyte (CD4+Th,CD8+CTL) , radiation-induced injury of normal tissue especially lung can be lessened by FTBI pattern.