中文摘要：

目的 探讨丹皮酚在体外对人肺腺癌A549细胞放射增敏作用的机制。方法 采取四甲基偶氮唑盐比色法（MTT）,测定丹皮酚对人肺腺癌A549细胞的抑制率。分为细胞对照组、单纯加药组、单纯照射组和药物联合照射组。通过克隆形成实验,观察丹皮酚对人肺腺癌A549细胞放射敏感性的影响。采用TUNEL染色与流式细胞仪,检测肿瘤细胞凋亡率,Western blot法观察细胞内Survivin蛋白的表达变化。结果 随着丹皮酚浓度的增加,丹皮酚对人肺腺癌A549细胞的抑制作用相应地增加,IC50为（25.2±2.1） mg/L。经克隆形成实验证实,丹皮酚对人肺腺癌A549细胞有明显的增敏效果,放射增敏比（SER）可达1.29。药物联合照射组的细胞凋亡较单纯照射组明显增加,呈现剂量-时间依赖效应（t＝4.95、3.03、3.78、4.59、2.88、3.70和5.54,P＜0.05）。同时,Western blot法检测出丹皮酚能够明显下调细胞内Survivin蛋白的表达,单纯给予不同浓度丹皮酚24 h后Survivin蛋白表达下调22.6%~56.7%（t=4.15、7.30和13.47,P＜0.05）;用丹皮酚预处理细胞再经6 Gy X射线照射后24 h,细胞内Survivin蛋白下调可达22.2％~69.4%（t=4.30、8.36和16.34,P＜0.05）。结论 丹皮酚在体外对人肺腺癌A549细胞有放射增敏作用,其机制可能是下调肿瘤细胞内Survivin蛋白的表达。

英文摘要：

Objective To investigate the radiosensitization effect and underlying mechanism of Paeonol on human lung adenocarcinoma cell line A549 in vitro. Methods Cells were assigned to following groups： control, Paeonol alone, irradiation alone, Paeonol combined with irradiation. The effect of Paeonol on cell proliferation was evaluated by the MTT assay. Clonogenic assay was performed to measure the radiosensitization effect of Paeonol under three concentrations around 20% IC50. Cell apoptosis was determined by TUNEL assay and flow cytometry （FCM）. The expression of Survivin protein was analyzed by Western blot. Results Cell growth was inhibited by Paeonol in a dose-dependent manner and the IC50 of Paeonol was （25.2±2.1） mg/L. Clonogenic assay showed that Paeonol could markedly enhance cell radiosensitivity and the sensitizing enhancement ratio （SER） was 1.29. After the pretreatment of Paeonol with different concentrations, radiation-induced apoptosis increased with the doses at 24,48,and 72 h post-irradiation （t=4.95,3.03,3.78,4.59,2.88,3.70,5.54,P〈0.05）. Moreover, the protein expression of Survivin was obviously down-regulated by 22.6%-56.7% （t=4.15,7.30,13.47,P〈0.05） due to the treatment of Paeonol. When the Paeonol-treated cells were further irradiated with 6 Gy X-rays, the expression of Survivin was reduced to 22.2%-69.4% （t=4.30,8.36,16.34,P〈0.05）. Conclusions Paeonol had radiosensitization effect on the human lung adenocarcinoma cell line A549 in vitro, where the down-regulated Survivin protein might be involved.