赫赛汀对大鼠膀胱肿瘤靶向治疗的体内研究

Targeted therapy with herceptin to rat bladder tumor model

目的研究赫赛汀(Herceptin)对大鼠膀胱肿瘤的治疗作用。方法50只SD大鼠随机分两组,对照组膀胱灌注生理盐水,实验组膀胱灌注N-甲基-N-亚硝基脲(N-methyl-N-nitrosourea,MUN),每3周1次,共4次,MNU总量为10mg;于灌注后第11周切开膀胱取标本,用光镜、免疫组化及RT-PCR方法对其诱发的膀胱肿瘤进行检测。筛选HER-2阳性表达的SD大鼠膀胱癌动物随机分为治疗组(Herceptin按20mg/kg腹腔注射)和非治疗组,检测赫赛汀作用后肿瘤大小、形态,计算抑瘤率,并用免疫组化S-P法检测HER-2蛋白表达、TUNEL法检测肿瘤细胞的凋亡情况,分析赫赛汀对膀胱肿瘤的作用。结果抑瘤率结果提示治疗组与非治疗组相比抑瘤率为50.0%,差异有统计学意义(P<0.05),免疫组化S-P法结果提示赫赛汀作用后HER-2蛋白表达下降;TUNEL原位凋亡结果提示治疗组凋亡指数(64.0±6.3)%高于非治疗组(47.9±5.4)%(P<0.05)。结论赫赛汀对HER-2阳性的实验性膀胱肿瘤有抑制生长、促进凋亡的作用。

Objective To investigate the therapeutic effect of herceptin to rat bladder cancer Methods Totally 50 SD rats were randomly divided into experimental group （n = 40） and control group （n = 10）. The rats of experimental group received a perfusion into the bladder with N-methyl-N-nitrosourea （MNU） at 2. 5 mg every time, once per 3 weeks for 4 times in all, while those of the control group underwent a perfusion with normal saline instead of MNU. In 1 week after the last perfusion, the bladders were slited for gross observation and the biopsies were carried out for pathological observation with HE staining. Immunohistochemical SP method and RT-PCR were applied to detect HER-2 protein and mRNA expression in tumor tissues. Then 16 rats with HER-2 positive bladder cancer were randomly and equally divided into treatment group （herceptin, 20 mg/kg by intraperitoneal injection, once per week for 6 weeks） and non-treatment group （ normal saline, 0. 5 ml）. Tumor weight, size and shape were measured and calculated for the inhibitory rate of herceptin. HE staining was carried out for the morphology of the tumor mass. The expression of HER-2 protein was detected with immunohistochemical SP method, and apoptosis in bladder tumor tissues with TUNEL method. Results The results of inhibitory rate was 50.0%, and it showed that the differences were statistically significant in treatment group compared with non-treatment group （ P 〈 0.05 ）. Immunohistochemical SP staining showed that the expression of HER-2 protein was significantly decreased after herceptin treatment. TUNEL assay indicated that the apoptotic index was higher in treatment group （64.0 ± 6.3）% than in non-treatment group （47.9± 5.4）% with significant difference （P 〈0.05）. Conclusion Herceptin suppresses the growth of tumor mass and improved apoptosis of tumor cells in experimental HER-2-positive bladder tumor in SD rats.