射频消融抑制小鼠乳腺癌肺转移

Radiofrequency ablation inhibits lung metastasis ofbreast cancer in mice

目的探讨射频消融术对小鼠三阴性乳腺癌肺转移和免疫系统的影响。方法小鼠乳腺癌4T1细胞系皮下接种于雌性Bal B／c小鼠右下肢处，肿瘤直径达到6—8mm时进行射频消融治疗，流式细胞术检测脾脏中各淋巴细胞亚群的变化，观察肺转移的情况。结果射频消融基本上可以消除原位肿瘤，原位肿瘤复发率较低；射频消融后，小鼠脾脏CD4^＋T细胞、CD8^＋T细胞、B细胞、自然杀伤细胞及自然杀伤T细胞数量都有所升高；射频消融治疗4T1肿瘤14d后，脱颈处死对照组和射频消融组小鼠，射频消融组和对照组4T1荷瘤小鼠的肺转移结节分别为（24±18）个和（81±35）个，差异有统计学意义（P=0．012）。射频消融抑制肺转移的机制与脾脏中CD4^＋T细胞、CD8^＋T细胞、B细胞和自然杀伤细胞的比例增加及髓系来源抑制细胞比例降低有关。结论射频消融增强了机体内抗肿瘤的免疫反应，抑制了小鼠4T1细胞乳腺癌的肺转移。射频消融术治疗三阴性乳腺癌和控制其远端转移可能会有良好的治疗效果。

Objective To explore the effects of radiofrequency ablation （RFA） on immune system and lung metastasis in a mouse model of triple negative breast cancer 4T1. Methods Mouse breast cancer 4T1 cells were injected into the fight hind limb of female Bal B/c mice. When the tumor size was 6-8 mm in diameter, RFA was used to treat the transplanted breast cancer in mice. We examined the splenic lymphocyte subsets by flow cytometry at different time points after RFA. Fourteen days after treatment, we sacrificed the mice of both control and treatment groups, counted the number of lung metastatic nodules, and detected the changes of splenic lymphocyte subsets by flow cytometry. Results RFA basically eliminated the orthotopic carcinoma with a low local recurrence rate. After the RFA treatment, the amount of spleic CD4^＋T cells, CD8^＋ T cells, B cells, NK and NKT cells was increased. Fourteen days after the RFA treatment, all mice were sacrificed, and the lung metastatic nodules were 24±18 in the control group and 81±35 in the RFA-treated group （P=0.012）. The mechanism of suppression of metastatic lung cancers was related to the increase of splenic CD4^＋ T cells, CD8^＋T cells, B cells and NK cells, and the decrease of myeloid-derived suppressor cells. Conclusions RFA can enhance the anti-tumor immunity and effectively inhibit lung metastasis of 4T1 cell-induced breast cancer, and has a good potential effect in the treatment of triple-negative breast cancer and the control of distant metastasis.