Background

Up to now, experimental studies on rodents have failed to provide definitive confirmation of the carcinogenicity of extremely low frequency electromagnetic fields (ELFEMF). Two recent studies performed in our laboratory on Sprague-Dawley rats reported a statistically significant increase in malignant tumors of different sites (mammary gland, C-cells carcinoma, hemolymphoreticular neoplasia, and malignant heart Schwannoma) when ELFEMF exposure was associated with exposure to formaldehyde (50 mg/l) or acute low dose of γ-radiation (0.1 Gy) (Soffritti et al., 2016a) (Soffritti et al., 2016b). The same doses of known carcinogenic agents (50 mg/l formaldehyde, or acute 0.1 Gy γ-radiation), when administered alone, previously failed to induce any statistically significant increase in the incidence of total and specific malignant tumors in rats of the same colony.

Objectives

A lifespan whole-body exposure study was conducted to evaluate the possible carcinogenic effects of ELFEMF exposure administered alone to Sprague-Dawley rats, as part of the integrated project of the Ramazzini Institute (RI) for studying the effects on health of ELFEMF alone or in combination with other known carcinogens.

Methods

Male and female Sprague-Dawley rats were exposed 19 h/day to continuous sinusoidal-50 Hz magnetic fields (S-50 Hz MF) at flux densities of 0 (control group), 2, 20, 100 or 1000µT, and to intermittent (30 min on/30 min off) S-50 Hz MF at 1000 µT, from prenatal life until natural death.

Results

Survival and body weight trends in all groups of rats exposed to ELFEMF were comparable to those found in sex-matched controls. The incidence and number of malignant and benign tumors was similar in all groups. Magnetic field exposure did not significantly increase the incidence of neoplasias in any organ, including those sites that have been identified as possible targets in epidemiological studies (leukemia, breast cancer, and brain cancer).

Conclusions

Life-span exposures to continuous and intermittent sinusoidal-50 Hz ELFEMFs, when administered alone, did not represent a significant risk factor for neoplastic development in our experimental rat model. In light of our previous results on the carcinogenic effects of ELFEMF in combination with formaldehyde and γ-radiation, further experiments are necessary to elucidate the possible role of ELFEMF as cancer enhancer in presence of other chemical and physical carcinogens.

中文翻译：

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单独暴露于Sprague Dawley大鼠的连续和间歇性极低频电磁场（ELFEMF）的寿命暴露结果

背景

到目前为止，对啮齿动物的实验研究未能提供对极低频电磁场（ELFEMF）致癌性的确定性确认。在我们的实验室中对Sprague-Dawley大鼠进行的两项最新研究报告，当ELFEMF暴露与甲醛（甲醛）暴露相关时，不同部位的恶性肿瘤（乳腺，C细胞癌，血淋巴状瘤和恶性心脏神经鞘瘤）的统计学显着增加。 50 mg / l）或急性低剂量的γ辐射（0.1 Gy）（Soffritti等，2016a）（Soffritti等，2016b）。单独服用相同剂量的已知致癌剂（50 mg / l甲醛或急性0.1 Gyγ射线），

目标

进行了一项终生全身暴露研究，以评估单独给予Sprague-Dawley大鼠的ELFEMF暴露可能产生的致癌作用，这是Ramazzini研究所（RI）的综合项目的一部分，该研究旨在研究单独或单独对ELFEMF的健康产生的影响与其他已知的致癌物合用。

方法

雄性和雌性Sprague-Dawley大鼠在19 h / day的通量密度分别为0（对照组），2、20、100或1000µT的情况下，暴露于连续的正弦50 Hz磁场（S-50 Hz MF），并间歇性地（从产前生命到自然死亡，在1000 µT时S-30 Hz MF开启30分钟/关闭30分钟。

结果

暴露于ELFEMF的所有大鼠组的存活率和体重趋势与性别匹配对照组中的存活率和体重趋势相当。在所有组中，恶性和良性肿瘤的发生率和数量均相似。磁场暴露并没有显着增加任何器官瘤形成的发生率，包括那些在流行病学研究（白血病，乳腺癌和脑癌）中已确定为可能靶点的部位。

结论

当单独使用时，寿命中连续和间歇性的50 Hz正弦曲线ELFEMF暴露并不代表我们实验大鼠模型中肿瘤发展的重要危险因素。根据我们先前关于ELFEMF结合甲醛和γ射线致癌作用的研究结果，有必要进行进一步的实验以阐明ELFEMF在其他化学和物理致癌物存在下作为癌症增强剂的可能作用。