Circadian effects of ionizing radiation on reproductive function and clock genes expression in male mouse

Abstract

Background Exposure to the ionizing radiation (IR) encountered outside the magnetic field of the Earth poses a persistent threat to the reproductive functions of astronauts. The potential effects of space IR on the circadian rhythms of male reproductive functions have not been well characterized so far. Methods Here, we investigated the circadian effects of IR exposure (3 Gy X-rays) on reproductive functional markers in mouse testicular tissue and epididymis at regular intervals over a 24-h day. For each animal, epididymis was tested for sperm motility, and the testis tissue was used for daily sperm production (DSP), testosterone levels, and activities of testicular enzymes (glucose-6-phosphate dehydrogenase (G6PDH), sorbitol dehydrogenase (SDH), lactic dehydrogenase (LDH), and acid phosphatase (ACP)), and the clock genes mRNA expression such as Clock, Bmal1, Ror-α, Ror-β, or Ror-γ. Results Mice exposed to IR exhibited a disruption in circadian rhythms of reproductive markers, as indicated by decreased sperm motility, increased daily sperm production (DSP), and reduced activities of testis enzymes such as G6PDH, SDH, LDH, and ACP. Moreover, IR exposure also decreased mRNA expression of five clock genes (Clock, Bmal1, Ror-α, Ror-β, or Ror-γ) in testis, with alteration in the rhythm parameters. Conclusion These findings suggested potential health effects of IR exposure on reproductive functions of male astronauts, in terms of both the daily overall level as well as the circadian rhythmicity.

Utility of melatonin in mitigating ionizing radiation-induced testis injury through synergistic interdependence of its biological properties

“…The testis is one of the most radiosensitive organs, and spermatogenic cells are the most sensitive cellular element to IR and non-IR due to high proliferation activity [ 3 ]. Recent study report that IR disrupted circadian rhythms of reproductive markers, including decreased sperm motility and disrupted clock gene expression in the testis [ 4 ]. Radiation exposure might cause infertility by lowering sperm count and testosterone levels by destroying Leydig and spermatogonial stem cells [ 5 ].…”

Neonatal vitamin A supplementation improves sheep fertility potential

“…The mRNA expression of the RAR-related orphan receptor A was also upregulated. ROR is involved in T biosynthesis and the regulation of semen quality and male fertility ( 43 , 44 ). RAR activates its transcription ( 45 ).…”

Effects of paternal ionizing radiation exposure on fertility and offspring's health

“… 6 , 7 , 8 The similar results of testicular dysfunction and adverse effects on offspring were also observed in animal models exposed to IR. 9 , 10 , 11 , 12 Since conception at short times after radiation exposure is likely to be avoided, the fertility recovery after radiation, and the long‐time health of offspring have inevitably become important issues to be addressed.…”