高能X线诱导胃癌种植瘤Fas表达上调及细胞凋亡的实验研究

目的　研究X线能否诱导胃癌细胞Fas表达及细胞凋亡变化 ,以了解胃癌中电离辐射、细胞凋亡及Fas表达之间的联系。方法　建立胃癌细胞系SGC - 790 1(低分化腺癌 )裸小鼠原位种植瘤模型 ;随机将 2 1只模型鼠分为未照射组和两个照射组 (每组 7只 ) ,对两个照射组行X线 (6MV ,2 0Gy)局部照射 ,分别于照射后 2 4、4 8h处死动物 ;采用免疫组化染色技术及TUNEL法 ,分别检测未照射组及照射组胃癌细胞的Fas表达状态及细胞凋亡的变化。结果　 (1)照射后 2 4h胃癌组织的凋亡指数 (AI)及Fas表达标记指数 (LI)明显高于未照射组 (P <0 .0 1) ;(2 )照射后 4 8h胃癌组织的AI及LI与未照射组比较 ,无显著差异 (P >0 .0 5 ) ;(3)AI、LI变化趋同 ,具有正相关性(P <0 .0 1)。结论　胃癌组织存在凋亡受抑现象 ,X线能诱导胃癌细胞凋亡及Fas表达上调 ;且X线诱导胃癌细胞凋亡可能是X线诱导Fas表达上调的结果

Establishment of Diffuse Type Stomach Carcinoma Orthotopic-Implanted Model and Study on Apoptosis Induced by X-ray

Objective To observe whether ionizing radiation could induce up-regulation of Fas receptor expression and apoptosis in diffuse type stomach carcinoma. To investigate the relationship among ionizing radiation, apoptosis and the expression of Fas in stomach carcinoma. Methods Firstly, the experimental model of SGC-7901 cell lines was set up and diffuse type stomach carcinoma orthotopically implanted in nude mice. Then 21 model mice were randomized into three groups equally i.e.,the control group (group A) and two irradiation groups(group B and group C, executed at 24 hours and 48 hours after irradiation respectively). The mice in group B and group C were irradiated with 6 MV X-rays at a dose of 20 Gy. By using the methods of TUNEL and immunohistochemical staining, the changes of apoptosis index and Fas expression in tumor tissues were examined. Results (1)The spontaneous apoptosis index (AI) of tumor tissues was significantly lower than that of mucosa tissues( P <0.01).(2)The AI of tumor tissues in group A was significantly lower than that in group B ( P <0.01), but there was no notable difference with that in group C ( P >0.05).(3)The Fas LI of tumor tissues increased after irradiation compared with the control group( P <0.05). (4)The changes of AI and Fas LI in all groups with similar tendency showed positive correlation( P <0.01). Conclusion The apoptosis of diffuse type stomach carcinoma is seriously restrained. Ionizing radiation can induce apoptosis and up-regulate the expression of Fas in diffuse type stomach carcinoma. The apoptosis induced by irradiation maybe depend on the up-regulating of Fas after irradiation.