γ射线对培养的兔血管平滑肌细胞的抑制作用

目的 观察体外培养的兔动脉平滑肌细胞(SMCs）对7射线照射的剂量效应关系，探讨电离辐射抑制SMCs增殖的细胞生物学机理。方法 静止期SMCs分别给予γ射线2．5，5，10，20及30Gy一次性照射后继续培养4，24或72h。以^3H—TdR掺入法、流式细胞术分析、微核实验和电镜观察γ射线对SMCs的DNA合成、增殖周期和损伤的影响。结果 在2．5Gy以上剂量γ射线一次性照射时，SMCs增殖明显抑制，细胞G0／G1期阻滞，均呈剂量依赖性。2．5Gy以下剂量γ射线照射后24h左右可见细胞凋亡增加，2．5Gy以上剂量7射线照射可使SMCs发生坏死。结论 电离辐射能抑制SMCs增殖，使细胞产生G0／G1期阻滞，并呈剂量依赖关系。SMCs死亡方式与受照射剂量有关。

Inhibitory effect of gamma radiation on cultured rabbit vascular smooth muscle cells

Objective Using in vitro cultured smooth muscle cells (SMCs) to examine the gamma radiation dose-response relationship and to investigate the cellular mechanisms by which radiation inhibits proliferation of SMCs. Methods Quiescent SMCs from rabbit illiac artery were irradiated with 2.5-30 Gy gamma rays,and immediately cultured in DMEM medium with 10% FCS for 4,24 and 72 hrs respectively. 3H-TdR,flow cytometry,micronucleus test,electron microscopy were carried out to determine the impacts of gamma radiation on DNA synthesis,cell cycle phase,and cellular damage of SMCs. Results Gamma radiation significantly inhibited SMCs proliferation in a dose-dependent manner and caused cell cycle G -0/G -1 arrest at the doses above 2.5 Gy.A low dose (<2.5-5 Gy) could increase SMCs apoptosis at 24 hrs after irradiation,while a high dose could cause their death. Conclusions Ionizing radiation probably inhibits SMCs proliferation dose-dependently and causes cell cycle G -0/G -1 arrest.At low dose level gamma radiation can induce apoptosis,while at high dose level it can kill SMCs directly. ;