Radiation effects on male fertility

Abstract

Background: Spermatogenesis is a process of dynamic cell differentiation. Ionizing radiation impairs spermatogenesis, and spermatogonia are more radiosensitive than spermatocytes or spermatids. Consistent with this assumption and due to improvement in tumor curability, nowadays, fertility preservation represents a public health need. Objectives: To discuss radiotherapy-induced risk to male fertility and raise oncologic awareness of male fertility in daily clinical practice. Materials and Methods: PubMed and Clinicaltrials.gov databases were searched for papers in English. Results: We provide an overview of clinical landscape. Four main issues were proposed: (i) spermatogenesis and radiobiological general concepts; (ii) impairment of spermatogenesis; (iii) impairment of testosterone-producing Leydig cells; (iv) clinical radiotherapy evidence in oncology. Conclusion: This review can be useful in daily clinical work and offer some directions for future research. RESULTSWe organized results into four sections: (i) spermatogenesis and radiobiological general concepts; (ii) impairment of spermatogenesis; (iii) impairment of testosterone-producing Leydig cells; and (iv) clinical evidence in human.

Current Insights and Latest Updates in Sperm Motility and Associated Applications in Assisted Reproduction

“…Exposure to a threshold of 0.1 Gy of ionizing radiation caused significant decrease in sperm parameters, which was reversible after 9-18 months. However, exposure to > 3 Gy caused permanent infertility [84]. Considering the extreme sensitivity of the testicular tissue to radiation-induced damages, it is a common practice to use lead shields to minimize the exposure to testes during radiotherapy.…”

Cryptorchidism after the Fukushima Daiichi Nuclear Power Plant accident:causation or coincidence?

“…Speiser et al assessed ten patients who received daily testicular doses of 0.12 Gy for a total dose of 1.4 -3.0 Gy ; all such patients had azoospermia, but only two of them for longer than 16 months 30) . De Felice et al reported that doses of irradiation > 0.35 Gy caused azoospermia, which was reversible in some cases 31) . The time taken for recovery increases with larger doses ; complete recovery takes place within 9 -18 months following radiation with < 1 Gy, but doses in excess of 2 -6 Gy may result in permanent azoospermia 31) .…”

“…De Felice et al reported that doses of irradiation > 0.35 Gy caused azoospermia, which was reversible in some cases 31) . The time taken for recovery increases with larger doses ; complete recovery takes place within 9 -18 months following radiation with < 1 Gy, but doses in excess of 2 -6 Gy may result in permanent azoospermia 31) . According to the International Atomic Energy Agency (IAEA), a dose of 1.0 Gy leads to a temporary reduction in the number of spermatozoa, that of 1.5 Gy leads to temporary sterility, and that of 5.0 to 6.0 Gy (acute) can produce permanent sterility in males 32) .…”

“…Doses that cause death of spermatocytes are higher than those for spermatogonia (2 -3 Gy) ; while spermatids are not damaged by such doses, after 4 -6 Gy a noticeable decrease in the sperm count can be observed 33) . De Felice et al reported that the susceptibility of Cryptorchidism after the Fukushima nuclear accident spermatogonia, spermatocytes, and spermatids to a single dose irradiation was < 1 Gy, 1 -3 Gy, and > 3 Gy, respectively 31) .…”

“…Leydig cells of the testis, which secrete testosterone, are remarkably more radioresistant than the germinal epithelium and are only injured by high therapeutic radiation doses 37) . Furthermore, Leydig cell function is usually preserved up to 20 Gy in prepubertal boys and 30 Gy in sexually mature men 31) .…”