Effects of environmental radiation on testes and spermatogenesis in wild large Japanese field mice (Apodemus speciosus) from Fukushima

Abstract

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident that occurred after the Great East Japan Earthquake in March 2011 released large quantities of radionuclides to the environment. The long-term effects of radioactive cesium (Cs) on biota are of particular concern. We investigated the accumulation of radioactive Cs derived from the FDNPP accident, and chronic effects of environmental radionuclides on male reproduction, in the large Japanese field mouse (Apodemus speciosus). In 2013 and 2014, wild mice were captured at 2 sites in Fukushima Prefecture and at 2 control sites that were distant from Fukushima. Although the median concentrations of 134Cs and 137Cs in the mice from Fukushima exceeded 4,000 Bq/kg, there were no significant differences in the apoptotic cell frequencies or the frequencies of morphologically abnormal sperm among the capture sites. Thus, we conclude that radiation did not cause substantial male subfertility in Fukushima during 2013 and 2014, and radionuclide pollution levels in the study sites would not be detrimental to spermatogenesis of the wild mice in Fukushima.

Rewilding of Fukushima's human evacuation zone

“…]); physiological damage (eg spermatogenesis in mice [ Apodemus argenteus and Mus musculus ; Okano et al . ]; hematopoiesis in macaques [ Macaca fuscata ; Urushihara et al . ]); and reproductive effects (in goshawks [ Accipiter gentilis fujiyamae ; Murase et al .…”

Low-dose radiation-induced risk in spermatogenesis

“…A 2016 study showed that although the median concentrations of 134 Cs and 137 Cs in the mice from Fukushima exceeded 4000 Bq/kg, there were no significant differences in the frequencies of apoptotic cells morphologically abnormal sperm amongst the capture sites (Okano et al 2016). The study concluded that the exposures in Fukushima during 2013 and 2014 were not detrimental to spermatogenesis in wild mice.…”

“…(Okano et al 2016) 9 Wild large Japanese field mice (Apodemus speciosus) captured in Fukushima Enhancement of spermatogenesis (Takino et al 2017) …”

Analysis of Radioactive Elements in Testes of Large Japanese Field Mice Using an Electron Probe Micro-Analyser after the Fukushima Accident

“…Okano et al [17] reported that, although the concentrations of 134 Cs and 137 Cs in wild mice from Fukushima exceeded 4000 Bq/kg, there were no significant differences in the frequencies of apoptotic cells or morphologically abnormal sperm when compared with wild mice from the non-contaminated control area. However, Kawagoshi et al [18] reported that the average frequencies of chromosomal aberrations in splenic lymphocytes of animals living in the heavily contaminated (approximately 3 mGy/day) area of Fukushima were higher than those of animals from the non-contaminated, slightly contaminated (approximately 0.03 mGy/day), and moderately contaminated (approximately 1 mGy/day) areas.…”