Epigenetics refers to how gene expression and function are modulated without modifying the DNA sequence but through subtle molecular changes or interactions with it. As spermatogenesis progresses, male germ cells suffer plenty of epigenetic modifications, resulting in the definitive epigenome of spermatozoa conditioning its functionality, and this process can be altered by several internal and external factors. The paternal epigenome is crucial for sperm function, fertilization, embryo development, and offspring's health, and altered epigenetic states are associated with male infertility with or without altered semen parameters, embryo quality impairment, and worse ART outcomes together with the future offspring's health risks mainly through intergenerational transmission of epigenetic marks. Identifying epigenetic biomarkers may improve male factor diagnosis and the development of targeted therapies, not only to improve fertility but also to allow an early detection of risk and disease prevention in the progeny. While still there is much research to be done, hopefully in the near future, improvements in high-throughput technologies applied to epigenomes will permit our understanding of the underlying epigenetic mechanisms and the development of diagnostics and therapies leading to improved reproductive outcomes. In this review, we discuss the mechanisms of epigenetics in sperm and how epigenetics behave during spermatogenesis. Additionally, we elaborate on the relationship of sperm epigenetics with sperm parameters and male infertility, and highlight the impact of sperm epigenetic alterations on sperm parameters, embryo quality, ART outcomes, miscarriage rates and offspring's health. Furthermore, we provide insights into the future research of epigenetic alterations in male infertility.
A one year study was carried out to determine the outcome of the seminal fluid parameters collected via masturbation and coitus interruptus in 151 patients who were undergoing intrauterine insemination (IUI) and patients who came for seminal analysis. There were no statistically significant differences in terms of volume, concentration, progressive motility and normal morphology from specimens collected via coitus interruptus compared to specimens collected via masturbation. Pregnancy outcomes were also comparable.
This study was performed to determine the effects of dietary vitamin E and soybean oil (a rich source of polyunsaturated fatty acids) on the sperm concentration and motility in male Sprague-Dawley rats. Rats with body weights between 250 - 300 gms were randomly allotted into five treatment groups with three animals each. The trial lasted 63 weeks inclusive of a one week acclimatization period. Rats were fed either CTRL (Base Diet + 5 % Soybean Oil + 3000 IU Vitamin E), BD Only (Base Diet Only), BDVitE (Base Diet + 3000 IU Vitamin E Only), BDSBO (Base Diet + Soybean Oil Only) or COMM (Imported Commercial Rat Pellets). At the end of the trial, the rats were euthanized and sperm concentration and motility were evaluated for both left and right testicles. It was found that although sperm motility had no significant difference across treatment groups, animals supplemented with adequate vitamin E and soybean oils had significantly higher concentration of sperms. It was also shown that vitamin E supplementation alone is more important than dietary fat supplementation in influencing sperm concentration in rats.
Thirteen sexually mature captive male lesser Malay chevrotains (Tragulus javanicus) were each anesthetized twice with tiletamine-zolazepam for electroejaculation. Viable spermatozoa were collected from all animals. The semen was creamy, milky, pale yellowish, or watery. The mean values for ejaculate volume, sperm concentration, and percentages of sperm motility, normality and viability were 23.7 +/- 2.5 microl, 366.9 +/- 127.8 x 10(6) spermatozoa/ml, 40.0% +/- 3.1%, 71.4% +/- 1.6%, and 59.6% +/- 2.1%, respectively. Semen pH was 7-8. No adverse effects of electroejaculation were noted. These are the first reported values for semen of lesser Malay chevrotain. Electroejaculation should be usable for routine semen collection in this species.
The declining trend of male fecundity is a major global health and social concern. Among numerous other confounding factors, variations in male fertility parameters in different regions have repeatedly been suggested to be influenced by geographic locations. The impact of overall lifestyle, behavioural patterns, ethnicity, work stress and associated factors upon health differ greatly between developed and developing countries. These factors, individually or in combination, affect male reproductive functions ensuing the discrepancies in semen qualities in connection with geographic variations. However, reports comparing semen characteristics between developed and developing countries are sparse. The present study finds its novelty in presenting a comparison in semen parameters of infertile men in the United States (n = 76) that fairly represents the population of a highly developed region and Iraq (n = 102), the representative of male populations of a developing region. Samples were collected and analysed according to WHO (WHO laboratory manual for the examination and processing of human semen, WHO; 2010) criteria by means of the Mann-Whitney test. The US population demonstrated lower sperm concentration, total count, and total and progressive sperm motility with a higher seminal total antioxidant capacity (TAC) as compared to the Iraqi population. This report encourages further investigations concerning the confounding factors leading to such alterations in semen qualities between these two geographic areas.
The aim of this study was to evaluate the effects of 8% virgin coconut oil (VCO) combined with different percentages of egg yolk in Tris extender on the quality of chilled and frozen-thawed bull semen. A total of 24 ejaculates from four bulls were collected using an electroejaculator. Semen samples were diluted with 8% VCO in Tris extender which contained different concentrations 0% (control), 4%, 8%, 12%, 16% and 20% egg yolk. The diluted semen samples were divided into two fractions: one was chilled and stored at 4°C until evaluation after 24, 72, and 144h; the second fraction was processed by chilling for 3h at 4°C to equilibrate, then packaged in 0.25ml straws and frozen and stored in liquid nitrogen at -196°C until evaluation after 7 and 14 days. Both chilled and frozen semen samples were then thawed at 37°C and assessed for general motility using computer-assisted semen analysis (CASA), viability, acrosome integrity, and morphology (eosin-nigrosin), membrane integrity (hypo-osmotic swelling test) and lipid peroxidation (thiobarbituric acid-reactive substances (TBARS)). The results indicate treatments with 8%, 12%, 16% and 20% egg yolk with 8% VCO had greater sperm quality (P<0.05) as compared with the control. The treatment with 20% egg yolk had the greatest sperm quality (P<0.05) among the treated groups for both chilled and frozen-thawed semen. In conclusion, the use of 8% VCO combined with 20% egg yolk in a Tris-based extender enhanced the values for chilled and frozen-thawed quality variables of bull sperm.