Endonuclease G is Upregulated and Required in Testicular Germ Cell Apoptosis after Exposure to 60 Hz at 200 μT

Title & Authors
Endonuclease G is Upregulated and Required in Testicular Germ Cell Apoptosis after Exposure to 60 Hz at 200 μT
Park, Sungman; Kim, Min-Woo; Kim, Ji-Hoon; Lee, Yena; Kim, Min Soo; Lee, Yong-Jun; Kim, Young-Jin; Kim, Hee-Sung; Kim, Yoon-Won;

Abstract
Several reports supported that continuous exposure to 60 Hz magnetic field (MF) induces testicular germ cell apoptosis in vivo. We recently evaluated duration- and dose-dependent effects of continuous exposure to a 60 Hz MF on the testes in mice. BALB/c male mice were exposed to a 60 Hz MF at $\small{100{\mu}T}$ for 24 hours a day for 2, 4, 6, or 8 weeks, and at 2, 20 or $\small{200{\mu}T}$ for 24 hours a day for 8 weeks. To induce the apoptosis of testicular germ cell in mice, the minimum dose is $\small{20{\mu}T}$ at continuous exposure to a 60 Hz MF for 8 weeks, and the minimum duration is 6 weeks at continuous exposure of $\small{100{\mu}T}$. Continuous exposure to a 60 Hz MF might affect duration- and dose-dependent biological processes including apoptotic cell death and spermatogenesis in the male reproductive system of mice. The safety guideline of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) indicates that the permissible maximum magnetic flux density for general public exposure is $\small{200{\mu}T}$ at 60 Hz EMF (ICNIRP Guidelines, 2010). In the present study, we aimed to examine the expression of pro- and anti-apoptotic genes regulated by the continuous exposure to 60 Hz at $\small{200{\mu}T}$ in Sprague-Dawley rats for 20 weeks. The continuous exposure to 60 Hz at $\small{200{\mu}T}$ does not affect the body and testicular weight in rats. However, exposure to 60 Hz MF significantly affects testicular germ cell apoptosis and sperm count. Further, the apoptosis-related gene was scrutinized after exposure to 60 Hz at $\small{200{\mu}T}$ for 20 weeks. We found that the message level of endonuclease G (EndoG) was greatly increased following the exposure to 60 Hz at $\small{200{\mu}T}$ compared with sham control. These data suggested that 60 Hz magnetic field induced testicular germ cell apoptosis through mitochondrial protein Endo G.
Keywords
60 Hz Magnetic Field;Apoptosis;Endonuclease G;Reproductive Function;Testicular Germ Cell;
Language
English
Cited by
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