Semen Abnormalities, Sperm DNA Damage and Global Hypermethylation in Health Workers Occupationally Exposed to Ionizing Radiation

Abstract

BackgroundCytogenetic studies have demonstrated that low levels of chronic radiation exposure can potentially increase the frequency of chromosomal aberrations and aneuploidy in somatic cells. Epidemiological studies have shown that health workers occupationally exposed to ionizing radiation bear an increased risk of hematological malignancies.ObjectivesTo find the influence of occupational radiation exposure on semen characteristics, including genetic and epigenetic integrity of spermatozoa in a chronically exposed population.MethodsThis cross sectional study included 134 male volunteers of which 83 were occupationally exposed to ionizing radiation and 51 were non-exposed control subjects. Semen characteristics, sperm DNA fragmentation, aneuploidy and incidence of global hypermethylation in the spermatozoa were determined and compared between the non-exposed and the exposed group.ResultsDirect comparison of the semen characteristics between the non-exposed and the exposed population revealed significant differences in motility characteristics, viability, and morphological abnormalities (P<0.05–0.0001). Although, the level of sperm DNA fragmentation was significantly higher in the exposed group as compared to the non-exposed group (P<0.05–0.0001), the incidence of sperm aneuploidy was not statistically different between the two groups. However, a significant number of hypermethylated spermatozoa were observed in the exposed group in comparison to non-exposed group (P<0.05).ConclusionsWe provide the first evidence on the detrimental effects of occupational radiation exposure on functional, genetic and epigenetic integrity of sperm in health workers. However, further studies are required to confirm the potential detrimental effects of ionizing radiation in these subjects.

Sperm quality and DNA damage in men from Jilin Province, China, who are occupationally exposed to ionizing radiation

“…The occupationally exposed men were from various hospitals with diagnostic radiation facilities (mainly computed tomography). All 46 men had operated the equipment for more than two years, and were considered to have been chronically exposed to low-dose radiation, as reported by Kumar et al (2013).…”

“…Exposure to ionizing radiation leads to a high incidence of de novo mutations in the Y chromosome (Arruda, 2009). There are significant differences in the semen characteristics motility, viability, and morphological abnormality between exposed and non-exposed populations (Kumar et al, 2013).…”

“…Previous studies have shown that health workers occupationally exposed to ionizing radiation experience an increased risk of hematological malignancies (Kumar et al, 2013). Ionizing radiation is a classical mutagen and is capable of inducing various kinds of stable and unstable chromosomal aberrations (Vellingiri et al, 2014).…”

“…The sperm DNA fragmentation index (DFI) is a good prognostic marker; a higher sperm DFI may be associated with a poor successful pregnancy rate, even after assisted conception, and may be associated with recurrent loss of the fetus (Venkatesh et al, 2011). Kumar et al (2013) reported that the level of sperm DNA fragmentation was significantly higher in a group that was occupationally exposed to radiation compared with a non-exposed group. There is a paucity of new data on sperm DNA damage in men from a Chinese population who are occupationally exposed to ionizing radiation.…”

Male fertility: Genome integrity and sperm DNA methylation

“…It is estimated that about 1 couple out of 7 over the world encounters difficulties to conceive a child [5] and male factor infertility accounts about half of the cases [6] . Male infertility can be due to multiple factors encompassing a wide variety of disorders including testicular failure and semen disorders that have been linked with genetics, environmental factors and epigenetic anomalies [7][8][9][10][11][12][13] . Thanks to the large development of non-invasive molecular biology tools and the easy access to biological samples, semen disorders became the most investigated and documented male infertility factor [14] .…”