【摘要】 目的探讨蚯蚓纤溶酶对胃癌细胞株MGC803的放射增敏作用及机制。方法采用克隆形成实验观察蚯蚓纤溶酶的放射增敏作用;流式细胞术观察药物对胃癌细胞株MGC803周期分布的影响;RT-PCR法检测药物对细胞内硒谷胱甘肽过氧化物酶(SeGPx)基因表达的影响。结果蚯蚓纤溶酶对胃癌细胞有放射增敏效应,100uku/L、300uku/L蚯蚓纤溶酶的放射增敏比分别为1.06和1.14。射线照射后MGC803细胞发生G1期阻滞,蚯蚓纤溶酶对细胞G1期阻滞无明显影响;PCR检测发现射线可诱导的SeGPxmRNA表达下调,蚯蚓纤溶酶能够增强射线诱导的SeGPxmRNA表达下调作用。结论蚯蚓纤溶酶能够增加胃癌细胞对放射线的敏感性,增敏机理可能与药物下调细胞内抗氧化酶SeGPx基因表达有关。更多还原

【Abstract】 Objective:To study the mechanism of radiosensitizing effect of fibrinolysin extracted from earthworm and its mechanism. Methods:Human gastric adenocarcinoma cell line MGC803 were treated with the fibrinolysin .Cell survival was determined by clonogenic assay. The cell cycle distribution was checked via flow cytometer after fibrinolysin treatment.RT-PCR was used to determine the gene expression of seleniun dependent glutathione peroxidase(SeGPx). Results:Under the experimental condition, fibrinolysin extracted from earthworm definitely enhanced radiosensitivity of MGC803 cells. Cell survival expriment showed sensitivity-enchancement-ratio of 1.06 and 1.14 for 100uku/l and 300uku/l of the fibrinolysin respectively;DNA flow cytometric analysis indicated that the fibrinolysin was incapable of abrogating the G_ 1 arrest induced by γ-rays;however,the the expression of SeGPxmRNA decreased after the fibrinolysin and γ-rays treatment. Conclusion:Fibrinolysin extracting from earthworm might be a pential radiodsensitizer for gastric adenocarcinoma. In addition, our data show that downregulating of SeGPxmRNA expression may play a key role in the radiosensitizing effect of the fibrinolysin.更多还原