激光免疫疗法对多发性皮肤鳞状细胞癌小鼠的抗肿瘤效应研究

Antineoplastic effect of laser immunotherapy in mice with multiple cutaneous squamous cell carcinoma

目的 探讨激光免疫疗法对多发性皮肤鳞状细胞癌（鳞癌）小鼠的抗肿瘤效应。方法 用紫外线持续照射SKH-1无毛小鼠建立免疫功能正常的小鼠多发性皮肤鳞癌模型后，分成激光免疫组、激光组、咪喹莫特组和对照组（每组5只）。激光免疫组：联合外用咪喹莫特乳膏及808 nm激光照射；激光组：仅予808 nm激光照射；咪喹莫特组：仅予咪喹莫特乳膏外用；对照组不予任何处理。治疗后记录小鼠瘤体体积、生存情况和肿瘤形态学变化。第27、60天用t检验和Mantel-Cox logrank检验两两比较4组小鼠背部瘤体体积和生存率。另取12只鳞癌小鼠分成4组，每组3只，治疗后第5天，取瘤体组织进行病理学观察。结果 第27天时，对照组和咪喹莫特组瘤体体积均较治疗前明显增大（均P 〈 0.05），激光组和激光免疫组瘤体无明显增大（均P 〉 0.05），其中咪喹莫特组瘤体体积略小于对照组（P 〉 0.05），而激光组和激光免疫组瘤体体积明显小于对照组（均P 〈 0.05）。第60天时激光组瘤体体积增大，体积明显大于激光免疫组（P 〈 0.05）。对照组小鼠在40 d内全部死亡；咪喹莫特组小鼠在50 d内全部死亡；激光组小鼠在第52、53天分别死亡1只，余存活60 d以上；激光免疫组小鼠在60 d内无死亡。第60天与对照组比较，咪喹莫特小鼠生存时间稍有延长，差异无统计学意义（P 〉 0.05）；激光组和激光免疫组小鼠生存时间明显延长（均P 〈 0.05），但激光免疫组与激光组间比较，差异无统计学意义（P 〉 0.05）。组织病理学显示咪喹莫特外用5 d无细胞死亡，而激光组及激光免疫组细胞大量死亡，瘤周可见多种炎症细胞，较对照组明显增多，尤以激光免疫组更明显。结论 激光免疫疗法是一种安全且有效的治疗皮肤鳞癌方法，尤其对多发性或转移性皮肤鳞癌具有潜在价值。

Objective To evaluate the antineoplastic effect of laser immunotherapy in mice with multiple cutaneous squamous cell carcinoma （CSCC）. Methods Normal immunocompetent hairless SKH-1 mice were consecutively irradiated by ultraviolet rays to establish mouse models of multiple CSCC. Then, 20 CSCC-bearing mice were randomly and equally divided into 4 groups： laser group irradiated with an 808-nm near-infrared laser （1 W/cm2, 10 minutes） once every two weeks for a total of 3 sessions, laser immunotherapy group irradiated with an 808-nm near-infrared laser as above and topically treated with imiquimod cream once a day for 3 days before and after each session of irradiation, imiquimod group treated with imiquimod cream as in the laser immunotherapy group, and control group receiving no treatment. The volume of tumors was calculated, and their morphology as well as the survival of mice were observed after the treatment. The t test and Mantel-Cox log-rank test were used to compare the volume of tumors on the dorsum and survival rates of mice, respectively, on days 27 and 60 after the start of treatment. Another 12 CSCC-bearing mice were randomly and equally divided into the 4 groups mentioned above, and tumor tissues were resected from these mice for histopathological examination on day 5 after the first treatment. Results On day 27, the volume of tumors significantly increased in the control group and imiquimod group （both P 〈 0.05）, but experienced no significant increase in either of the other two groups compared with that before the start of treatment （both P 〉 0.05）. Moreover, the volume of tumors in the control group was slightly larger than that in the imiquimod group （P 〉 0.05）, but significantly larger than that in the laser group and laser immunotherapy group （both P 〈 0.05）. The volume of tumors in the laser group increased, and was significantly larger than that in the laser immunotherapy group on day 60 （P 〈 0.05）. Mice all died within 40 days in the control group, and within 50 days in the imiquimod group; one mouse died on days 52 and 53 separately, and the other mice all survived longer than 60 days in the laser group; no mice died within 60 days in the laser immunotherapy group. By day 60, the survival time of mice was slightly longer in the imiquimod group （P 〉 0.05）, significantly longer in the laser group and laser immunotherapy group compared with the control group （both P 〈 0.05）, but similar between the laser group and laser immunotherapy group （P 〉 0.05）. Histopathological examination showed that 5-day topical application of imiquimod cream did not cause death of tumor cells, but numerous tumor cells died in the laser group and laser immunotherapy group. Multiple inflammatory cells were observed around the tumors, and the number of the inflammatory cells was obviously larger in both the laser group and laser immunotherapy group, especially in the latter group, compared with the control group. Conclusion Laser immunotherapy is a new effective and safe treatment for CSCC in mice, and has potential value especially in the treatment of multiple or metastatic CSCC.