氩氦刀冷冻联合CpG寡脱氧核苷酸治疗小鼠皮下移植性结肠癌

目的 探讨氩氦刀冷冻消融联合CpG寡脱氧核苷酸（ODN）对小鼠移植性结肠癌的治疗作用.方法 BALB/c小鼠皮下接种结肠癌CT26细胞建立荷瘤鼠模型,小鼠被分成PBS组（6只,瘤周注射PBS组）、氩氦刀组（6只,氩氦刀冷冻组）、CpG ODN组（6只,瘤周注射CpG ODN）和联合治疗组（6只,氩氦刀冷冻加瘤周注射CpG ODN）.观察各组小鼠存活及肿瘤生长情况;采用酶联免疫吸附试验检测小鼠外周血中IL-12和IFN-γ的含量;利用流式细胞仪检测小鼠外周血中CD3＋CD4＋T细胞与CD3＋CD8＋T细胞比例;对氩氦刀组和氩氦刀联合CpG ODN组治愈小鼠进行再攻击实验,观察小鼠再次成瘤率.结果 氩氦刀组和联合治疗组小鼠的平均生存时间为（80.3±5.4）d和（83.8±5.5）d,明显长于PBS组[（53.7±3.7）d]和CpG ODN组[（51.5±6.8）d],差异均有统计学意义（P＜0.05）.氩氦刀组和联合治疗组抑瘤率分别为83.8%和86.2%.治疗后20 d,氩氦刀组和联合治疗组的CD3＋CD4＋T细胞/CD3＋CD8＋T细胞比值、IL-12和IFN-γ水平均高于PBS组和CpGODN组,差异有统计学意义（P＜0.05）;与氩氦刀组比较,联合治疗组CD3＋CD4＋T细胞/CD3＋CD8＋T细胞比值差异无统计学意义,但IL-12和IFN-γ水平则显著升高（P＜0.05）.肿瘤再攻击后,氩氦刀组和联合治疗组分别有5只（5/6）和1只（1/6）再次成瘤,差异有统计学意义（P＜0.05）.结论 氩氦刀冷冻联合CpG ODN可以增强荷瘤鼠的抗肿瘤免疫应答,增强了氩氦刀治疗小鼠的免疫功能,减少了肿瘤再次攻击的成瘤率.

Efficacy of cryoablation combined with CpG oligonucleotides in the treatment of murine transplanted colon carcinoma

Objective To investigate the efficacy of cryoablation combined with CpG ODN in the treatment of murine transplanted colon carcinoma. Methods Colon carcinoma model was established by subcutaneously inoculating CT26 cells into the right flank in BALB/c mice. The tumor-bearing mice were randomly divided into 4 groups:the group of PBS injected in peritumoral area, the group of cryoablation, the group of cryoablation combined with CpG ODN, the group of CpG ODN injected in peritumoral area. The tumor size changes were measured. Serum levels of interleukin (IL) -12 and interferon-γ (IFN-γ) were assayed by ELISA. The rates of CD3+CD4+T, CD3*+D8*+ lmyphocytes in serum were counted with flow cytometry. Mice in the cryoablation group and the combined group with tumor regression were re-challenged with CT26 cells. Results The survival time of cryoablation group and combined therapy group were (80.3±5.4) days and (83.8±5.5) days, respectively, longer than (53.7±3.7) days in PBS group and (51.5±6.8) days in CpG ODN group(all P<0.05). The suppress rates of tumor cells in cryoablation group and combined therapy group were 83.8% and 86.2% respectively. After 20 days following treatment, CD3+CD4+T/CD3+CD8+T ratio and the concentrations of IL-12 and IFN-γ in mice serum of cryoablation group and combined therapy group were higher than those in PBS group and CpG ODN group (all P<0.05). No significant difference was found in CD3+CD4+T/CD3+CD8+T ratio between cryoablation group and combined therapy group (P>0.05). However, the concentrations of IL-12 and IFN-γ in combined therapy group were higher than those of cryoablation group (all P<0.05). After re-challenging, tumor formation rate in the cryoablation combined with CpG ODN group was 16.7%, significantly lower than that in the cryoablation group(83.8%) (P<0.05) Conclusion Cryoablation combined with CpG ODN can increase antitumor immune response in mice, and therefore can decrease the tumor formation when re-challenged with CT26 cells.