放射诱导胃癌细胞凋亡的实验研究

Experimental Study of Human Gastric Cancer Cell Apoptosis Induced by Radiotherapy

目的：建立放射诱导胃癌细胞凋亡模型，为进一步研究细胞凋亡分子机理打下基础。方法：用直线加速器12Gy9MeV 照射培养的人胃癌细胞株SGC－7901，诱导凋亡发生，检测DNA条带变化，电镜观察凋亡小体的出现，流式细胞仪检测凋亡率及细胞周期和细胞内Ca2＋、cAMP浓度。结果：照射后2小时，即有凋亡细胞出现，在72小时达高峰，胃癌细胞DNA结构断裂，电泳呈梯状带形。胃癌细胞形态学改变出现膜小泡和凋亡小体形成等凋亡细胞特征。FCM检测出现典型的凋亡峰，以G2～M期凋亡率为最高，照射后2、24、48、72小时凋亡率分别为11．26％、38．39％、50．59％及59．47％，胞内Ca2＋和cAMP浓度变化也随凋亡率增加而升高。结论：照射12Gy9MeV诱导胃癌细胞株SGC－7901发生凋亡，凋亡率在72小时达高峰。胞内Ca2＋和cAMP浓度变化起了相当重要的作用。

Objective To establish a cell apoptotic model of human gastric cancer cell as a base to study the molecular mechanism of gastric cancer cell apoptosis induced by radiotherapy． Methods Human cultured gastric cancer cell line SGC－7901 was exposed in vivo to radiotherapy 12Gy 9MeV． Cell apoptosis was ascertained by cell morphology under transmission electron－microscope DNA electrophoresis low cytometry and intracellular Ca2＋ cAMP were determined． Results When SGC－7901 cells were treated with radiotherapy for 2h cell apoptosis occurred． Typical apoptosis bodies appeared and DNA ladder could be demonstrated on DNA electrophoresis． Apoptotic peak was also shown by flow cytometry G2～M phase cell cycle had the highest apoptotic rate． After radiotherapy 2 24 48 72 hours the apoptotic rate increased respectively． Intracellular Ca2＋ cAMP gradually increased with the apoptotic rate． Conclusion The apoptosis of human cultured gastric cancer cells SGC－7901 cell line is successfully induced by radioaction． The apoptotic peak reaches after radiotherapy 72h． Intracellular Ca2＋ cAMP changes play an important role to induce the SGC－7901 cells apoptosis by radioaction．