A Study On The Effects Of Extremely Low Frequency Electromagnetic Fields On The Male Reproduction And Its Mechanism In Mice

In recent years, growing attention has been focused on the possible effect of extremely low frequency electromagnetic fields (ELF EMFs) on human reproductive health. Some epidemiological and experimental studies have suggested that ELF EMFs is associated with male infertility. However limited experimental studies have not come at an exact conclusion. Present experiments were performed on healthy adult male mice. Male reproductive effects induced by exposure of 0.2~6.4mT 50Hz ELF EMFs for 2 or 4 weeks were observed through morphological, biochemical and cell-biological methods and approaches.The results are as follows:1. The testis weight and volume were decreased after EMFs exposure, and the effect of 4week EMFs exposure is more obvious than that of 2week exposure; No significant histopathological changes were observed in the testis of exposed mice. Sperm count and sperm motility were decreased and incidence of teratospermia was increased after EMFs exposure.2. After EMFs exposure, SOD and GSH-px activity were decreased. Anti OH capacity ,NO content were increased and MDA content was decreased in the epididymis.3. DMA damage were detected by single-cell gel electrophoresis assay. After exposure the relative tail length of the comets and cells with DNA migration were increased.4. The percentages and DNA content in different testis cell regions and percentages of testis cells in different cell phases were estimated by flow cytometry (FCM) . After 6.4mT exposure for 2 weeks, the percentage of 1C testis cells was significantly decreased. And the percentage of 2C cells was significantly increased after 4 weeks exposure. The percentage of 1C and 2C cells were significant increased and decreased respectively for 4 week exposure compared with 2week exposure. DNA content of the mice exposed to 6.4 mT for 4 weeks was significantly decreased. The cell percentage in Sphase was increased after 6 4mT exposure for 2 weeks. 5. The influence of ELF EMFs on sperm chromatin structure is detected bysperm chromatin structure assay. Spermatozoa with denatured DNA (cellsoutside the main population, COMP T) were increased after all EMFsexposure for 4 weeks. These results indicated that: 1 50Hz EMFs exposure induced the decreases in adult mice testis weight, testisvolume, sperm count and sperm motility, and the increases in the incidence ofteratospermia in mice. As a result, 50Hz EMFs may have the potential toimpair male fertility.2. 50Hz EMFs could interfere the balance between cellular oxidative and anti-oxidative processes in male gonad tissue and thereby induce oxidative damage The findings also suggest that epididymis may be more susceptible to the oxidative stress induced by EMFs.3. The oxidative damage could be one of the mechanisms by which EMFs caused adverse effects on male reproduction in mice. The accumulated reactive oxygen species could attack DNA, disturb sperm chromatin structure and cell cycle of spermatogenesis.4. The biological effects of ELF EMFs could be organ- and tissue-specific.5 Long-term exposure to EMFs may have adverse effects on spermatogenesis.To sum up, this study provides an insight into the possible adverse effects and potential mechanism of the ELF EMFs on male reproduction in mice It is suggested that ELF EMFs could cause oxidative stress in testis and epididymis tissue, damage DNA and chromatin structure, interfere cell cycle and as a consequence disturb spermatogenesis. While EMFs may act as a physical agent to impair male reproduction, environmental supervision as well as prevention and protective measure should be intensified on fertile male population.