γ射线诱发细胞程序性死亡的时间及剂量效应研究

RESEARCH ON TIME A:ND DOSE EFFECTS OF γ-VINDUCED PROGRAMMED CELL DEATH

通过对辐射所致程序性细胞死亡（ＰＣＤ）的研究，揭示了射线诱发小鼠胸腺细胞ＰＣＤ生成的时间及剂量效应规律，采用不同的检测ＰＣＤ方法（ＤＮＡ片段分析法及流式细胞术），比较了不同组织的辐射敏感性差异。结果表明：照射后４～６ｈ诱发胸腺细胞ＰＣＤ生成最多。不同剂量照射，照后６ｈ取胸腺，发现２０Ｇｙ时胸腺细胞ＰＣＤ生成最多。脾、胸腺对辐射敏感，小剂量（１Ｇｙ）即可检测到ＰＣＤ形成；而心脏、大脑、肾对射线不敏感，照射１０Ｇｙ以上时，才能检测到ＰＣＤ。

Time courses and dose resPOnses of γ-induced programmed celldeath (PCD) in murine thymocytes after in vivo irradiation were studied, twomethods (analysis of DNA fragmentation and flow cytometry) to determine PCDwere implemented. The radiation sensitivity of different tissues was compared. Itcould be observed that the peak incidence of PCD occurred in thymocytes 4-6 hafter irradiation. On the basis of this result, 6 h after irradiation was chosen forthe determination of the dose response. The dose responses for thymocytes reacheda plateau after dose of 20 Gy. Spleen and thymus, the radiosensitive organs, after1 Gy γ-irradiatiom PCD could be detected,while the heart, brain and kidney,the nonradiosensitive organs, PCD could only be detected after doses of 10 Gy and above.(Institute of Basic Medical Sciences, Acadamy of Military Medical Sciences.Dening 100850)