Low-dose radiation-induced risk in spermatogenesis

Abstract

Purpose: To discuss low-dose radiation-induced risks to male fertility focusing on potential mechanisms of low-dose radiation-induced damage on spermatogenesis, epidemiological studies of environmental radiation effects on sperm parameters and transgenerational effects following exposure of spermatogonial stem cells (SSCs). Background: Spermatogenesis produces mature male gametes, spermatozoa, which fertilize their counterpart female gametes, oocytes. The robust maintenance system of spermatogenesis is essential for genomic conservation; however, male fertility can be readily impacted by exposure to environmental, chemical and physical factors including ionizing radiation. The mammalian testes are known to be radiosensitive yet the underlying molecular mechanisms of low-dose radiation-induced risks for spermatogenesis remain unclear. Furthermore, evidence characterizing transgenerational effects following exposure of SSCs remain controversial. Conclusions: Current concerns over the possible effects of low-dose radiation exposure on spermatogenesis requires further elucidation that may be resolved comparing and integrating observed experimental and epidemiological data. ARTICLE HISTORY

Radiation effects on male fertility

“…In physiological conditions, it takes around 70 days. Spermatogonial stem cells are able both to self‐renew to maintain stem cell populations and to generate progenitor cells that proceed through mitosis, meiosis, and finally morphological transformation of the haploid cells into spermatozoa (Fukunaga et al ., ). Failure of the spermatogonial stem cell population to function properly results ultimately in spermatogenesis failure.…”

“…But, as in all radiation accident reports, the main limit was that doses were not accurately known, as well as data fertility before accidental irradiation. However, after Chernobyl accident, there was much public concern over environmental radiation contamination and occupational exposures and effects on human male fertility (Fukunaga et al ., ). Recently, the International Commission on Radiological Protection (ICRP) updated the guidance on the control of exposure from radiation sources, based on the latest available scientific information of the atomic bomb survivors with 40–50 years of follow‐up (Stewart et al ., ).…”

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

“…To date, low-dose radiation effects on physiological processes including spermatogenesis remain unclear. Further studies are required to confirm these low-dose radiation effects [14].…”

“…This system provides critical information for the understanding of environmental pollution, biodistribution, radionuclide metabolism, dose evaluation, and the biological effects of internal and external exposure to radiation caused by nuclear disasters. In particular, experimental studies of low-dose rate (LDR) radiation exposure induced effects on spermatogenesis, along with indications from the nuclear disaster in Fukushima, will provide a more comprehensive radiobiological understanding of response mechanisms leading to improved accuracy in the estimation of human reproduction and health risk [14].…”

The Effect of Low Temperatures on Environmental Radiation Damage in Living Systems: Does Hypothermia Show Promise for Space Travel?

“…The study shed light on the effects of this exposure on spermatozoa, noting changes in their motility characteristics, global hypermethylation, increased incidences of morphological abnormalities in sperm, and sperm DNA fragmentation [ 91 ]. Such epidemiological investigation is of importance to provide new insights into environmental radiation risks on human fertility [ 92 ]. If a hypothermic state can induce an impairment of the radiation-induced damage repair response, hibernating astronauts might be more vulnerable to the chronic effects of radiation, compared to those allowed to travel under optimum-temperature sleeping conditions.…”