不同放射剂量的^125I粒子对人低分化胃癌细胞影响的动物实验研究

目的探讨不同放射剂量的^125I粒子对BGC823人低分化胃癌细胞的影响。方法将BGC823人低分化胃癌细胞悬液种植于64只BLAB nu/nu裸鼠的皮下,以制备荷瘤鼠模型。待荷瘤鼠模型饲养3周左右、肿瘤生长至0.7-1.2 cm时,将其随机分为4组：空白对照组、低剂量组、中剂量组及高剂量组（n=16）。其中,空白对照组裸鼠植入空白粒子,低、中及高剂量组分别植入放射剂量为1.48×10^-7、2.22×10^-7及2.96×10^-7 Bq的^125I粒子。分别于粒子植入前、植入后7、14、21及28 d,4组均随机抽取4只荷瘤鼠处死,剥取瘤体称重,并计算肿瘤体积;分别于植入粒子后14d和28d,测量4组荷瘤鼠肿瘤组织的细胞凋亡率和细胞周期因子E（cyclinE）mRNA的表达水平。结果①除空白对照组外（空白对照组的变化不大）,低、中及高剂量组的肿瘤体积和肿瘤质量随时间延长均呈下降趋势。粒子植入后7、14、21及28d,低、中及高剂量组的肿瘤体积和肿瘤质量均小于（轻于）空白对照组（P〈0.05）,且在28 d时,低剂量组的肿瘤体积和肿瘤质量均小于（轻于）中剂量组和高剂量组（P〈0.05）。②14d和28d时,低、中及高剂量组的凋亡率均高于空白对照组（P〈0.05）,而cyclinE mRNA的表达水平均低于空白对照组（P〈0.05）。28d时,低剂量组的凋亡率高于中剂量组和高剂量组（P〈0.05）,而cyclinE mRNA的表达水平却低于该2组（P〈0.05）。同组内与14d比较,28 d时除空白对照组的差异无统计学意义外（P〉0.05）,其余3组的凋亡率均较高（P〈0.05）,而cyclinE mRNA的表达水平均较低（P〈0.05）。结论 ^125I粒子组织间植入可有效抑制人低分化胃癌组织的生长,可抑制其cyclinE mRNA的表达;与其他剂量相比（2.22×10^-7 Bq及2.96×10^-7 Bq）,低剂量（1.48×10-7 Bq）的125I粒子持续照射可诱导BGC823人低分化胃癌细胞的凋亡增加。

Animal Experiment on Influence of Different Radiation Doses of ^125I Seed on Human Poorly Differentiated Gastric Cancer Cells

Objective To explore the influence of different radiation doses of ^125I seed on human poorly differentiated gastric cancer cells （BGC823）. Methods Sixty four male nude mice of BLAB nu/nu inoculated with human poorly differentiated gastric cancer cells （BGC823） were took as animal models. When tumors of nude mice grew to 0. 7-1.2 cm, the nude mice were randomly divided into blank control group, low dose group, middle dose group, and high dose group （n=16）. The tumors of nude mice in blank control group were implanted with blank seed, but tumors of nude mice in low dose group, middle dose group, and high dose group were implanted with ^125I seed （the radiation doses of 3 groups were 1.48×10^-7 Bq, 2.22×10^-7 Bq, and 2.96×10^-7 Bq respectively）. Four nude mice of 4 groups were randomly collected to measure the tumor volume and weight before implantation, and on 7, 14, 21, and 28 days after implantation, but apoptosis rates and expression levels of cyclinE mRNA were measured on 14 days and 28 days after implantation, by using flow cytometer and semi quantitative RT-PCR method respectively. Results ① Except for the blank control group, the tumor volume and weight decreased over time in low dose group, middle dose group, and high dose group. The tumor volume and weight in blank control group were higher than those of other 3 groups on 7, 14, 21, and 28 days after implantation （P〈0. 05） ; in addition, on 28 days after implantation, tumor volume and weight in low dose group were lower than those of middle dose group and high dose group （P〈0.05）. ② On 14 days and 28 days after implantation, the apoptosis rates of blank control group were lower than those of other 3 groups （P〈 0. 05）, but expression levels of cyclinE mRNA were all higher than those of other 3 groups （P〈0. 05）. In addition, on 28 days after implantation, apoptosis rate of low dose group was higher than both of middle dose group and high dose group （P〈 0. 05）, but expression level ofcyclinE mRNA was lower