Low-level light therapy has been used in healthcare as a therapeutic strategy for different diseases. However, its effects on cancer are controversial. This work evaluated the effects of three energies on breast cancer-bearing mice after a single red light-emitting diode (LED) irradiation. 4T1 cells were inoculated into the mammary fat pad of female BALB/c mice. When tumor volume reached 100 mm3 , animals were irradiated by a LED irradiator (660 ± 11 nm) with energies of 1.2, 3.6, and 6.0 J. Control without irradiation and healthy animals were also evaluated. Mice were monitored regarding tumor volume and total blood count. After euthanasia, their organs were examined. We observed that a single irradiation does not increase tumor volume. All irradiated groups exhibited better clinical conditions than control, which presented a significant decrease in platelet and red blood cell levels compared to healthy mice. The energy of 3.6 J arrested neutrophil-lymphocyte rate besides promoting longer survival and a lower number of metastatic nodules in the lungs. These findings suggest that a single red LED irradiation causes no impact on the course of the disease. Besides, the intermediary dose-effect should be further investigated since it seems to promote better outcomes on breast cancer-bearing mice.

中文翻译：

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单次红光照射对乳腺肿瘤小鼠的安全性和临床影响

低强度光疗法已在医疗保健中用作不同疾病的治疗策略。然而，它对癌症的影响是有争议的。这项工作评估了单次红色发光二极管 (LED) 照射后三种能量对乳腺癌小鼠的影响。将 4T1 细胞接种到雌性 BALB/c 小鼠的乳腺脂肪垫中。当肿瘤体积达到 100 mm3 时，用能量为 1.2、3.6 和 6.0 J 的 LED 辐照器 (660 ± 11 nm) 对动物进行辐照。还评估了未辐照的对照和健康动物。监测小鼠的肿瘤体积和总血细胞计数。安乐死后，他们的器官被检查。我们观察到单次照射不会增加肿瘤体积。所有照射组均表现出比对照组更好的临床状况，与健康小鼠相比，血小板和红细胞水平显着降低。3.6 J 的能量除了促进更长的存活时间和肺部转移性结节的数量更少之外，还抑制了中性粒细胞 - 淋巴细胞的速率。这些发现表明，单一的红色 LED 照射不会对疾病的进程产生影响。此外，应该进一步研究中间剂量效应，因为它似乎可以促进患乳腺癌小鼠的更好结果。