125Ⅰ粒子组织间植入对大肠癌的抑制作用及其机制

目的探讨125Ⅰ粒子抑制大肠癌生长的作用及其机制.方法采用雄性BALB/C裸小鼠建立人类大肠癌HCT-8细胞株的裸小鼠皮下移植瘤模型,将荷瘤鼠分5组(每组10只),对照组、空剂量组(0 Bq)、低剂量组(7.4×106 Bq)、中剂量组(14.8×106 Bq)、高剂量组(29.6×106 Bq),原位末端标记法检测肿瘤细胞凋亡的情况,免疫组织化学SP法染色检测血管内皮生长因子(VEGF),行微血管密度记数(MVD),同时检测p53蛋白表达情况.结果125Ⅰ粒子组织间植入治疗大肠癌,高、中、低剂量组抑瘤率分别为46.2%、34.0%、21.5%.在高剂量组中,p53蛋白表达增加,凋亡细胞增多,MVD及VEGF减少.结论(1)确证了125Ⅰ粒子对大肠癌治疗的有效性.(2)125Ⅰ粒子的推荐剂量14.8×106～29.6×106Bq.(3)125Ⅰ粒子组织间植入抑制肿瘤新生血管生成,同时p53蛋白表达量增加,细胞凋亡增多.

Iodine-125 interstitial brachytherapy in colorectal cancer inducing apoptosis

Objectives To study the inhibition of iodine-125 on the growth of colorectal cancer cells and the mechanism.Methods The animal models of the HCT-8 tumor were estabilished first through the injection of the cells into nude mice sbcutaneously,followed by the implant of the iodine-125 granules at different dosages into the tumor mass.The animals were divided into 5 groups (10 nude mice in each group),receiving different dosages of iodine-125 granules respectively (high-,middle-,low-,zero-,control).TUNEL method was used to detect the apoptosis of tumor cells.Immunohistochemistry S-P staining was used to measure the VEGF and p53 protein.Microvascular density was recorded.Results In the in vivo study,the inhibitary rate in high,middle and low dosage groups in the HCT-8 nude mouse tumor model was 46.2%, 34.0% and 21.5% respectively.The expression of p53 protein and apoptosis were increased,while MVD and VEGF was reduced in high dosage group.Conclusion (1)This study verifies the efficiency of the iodine-125 granules in inhibiting the growth of colorectal cancer;(2) The dosage range of iodine-125 is between 0.4 and 0.8 mCi;(3) Iodine-125 interstitial brachytherapy inhibites vascularization and induces the expression of p53.