吉西他滨对Lewis肺癌放射增敏的实验研究

目的　吉西他滨是一种核苷类似物,能够掺入到肿瘤细胞的DNA分子中,有效抑制DNA合 成。本实验观察联合应用吉西他滨和放疗治疗荷Lewis肺癌实体瘤C57BL小鼠的疗效,以明确吉西他滨 对Lewis瘤的放射增敏作用。方法　建立小鼠Lewis肺癌实体瘤模型后,分对照组、单纯放疗组、吉西他滨 组及吉西他滨联合放疗组。对照组给予腹腔注射生理盐水0.1ml,单纯放疗组荷瘤鼠右下肢肿瘤局部以 34Gy射线照射,吉西他滨组分两个亚组,分别以25mg/kg、50mg/kg吉西他滨腹腔注射,联合放疗组则以 25mg/kg吉西他滨腹腔注射加荷瘤鼠右下肢肿瘤局部34Gy射线照射。然后每两天测量肿瘤的长、短径, 比较各组瘤体积、肿瘤生长延缓天数、荷瘤鼠存活数和肺转移率等。结果　与对照组比较,25mg/kg和 50mg/kg的单剂量吉西他滨都对Lewis实体瘤生长有抑制作用(P<0.05);联合放疗组局部肿瘤生长受 到明显抑制,抑瘤率为86.6%,明显高于单纯放疗组(64.7%,P<0.05)和吉西他滨组(47.3%,P< 0.05);联合放疗组肿瘤生长延缓天数(瘤体积0.3～1.0cm3)超过9天,高于单纯放疗组(5天,P<0.05) 和吉西他滨组(3天,P<0.05);联合放疗组60天内存活的鼠最多(4个),单纯放疗组为2个,其他两组鼠 全部死亡。联合放疗组平均肺转移为0.5个/叶肺,单纯放疗组为1.5个/叶肺,吉西他滨组

Experimental Study on Improving Radiosensitivity for Lewis Lung Cancer with Gemcitabine

Objective Gemcitabine (dFdC) is an analogue of nucleoside.By incorporating into DNA strand,it can halt elongating DNA and kill tumor cells.The aim of this study was to determine the radiosensitivity on Lewis lung cancer with gemcitabine.Methods Mice bearing Lewis tumor were randomly divided into-control,radiation,gemcitabine and combination of gemcitabine with radiation groups.The parameters of tumor growth,inhibition of growth,the number of surviving mice and metastasis were observed after treatment.Results Single dose of 25mg/kg or 50mg/kg of gemcitabine had significant inhibiting effect on the growth of Lewis tumor.Tumor growth inhibition in combination group ( 86.6%) was higher than that of radiation group and gemcitabine group ( 64.7% and 47.3%,respectively,P< 0.05).Time of tumor growth delay (volume from 0.3 to 1.0cm 3) was beyond 12 days in combination group,3 days and 6 days in radiation group and gemcitabine group,respectively (P< 0.05).4 mice survived beyond 60 days in combination group,2 mice in radiation group,and none in the other two groups.The number of lung metastatic tumor in combination group was 0.5 per lung lobe,which was fewer than that in control group ( 3.2 per lung lobe,P< 0.01),radiation group ( 1.5 per lung lobe,P< 0.05),and gemcitabine group ( 1.8 per lung lobe,P< 0.05).Conclusions Gemcitabine could increase radiosensitivity of Lewis tumor and result in significant inhibition of growth of tumor and metastasis.The results showed that it was a better method to treat tumor by radiotherapy combined with gemcitabine.