Reactive oxygen species-induced alterations in H19-Igf2 methylation patterns, seminal plasma metabolites, and semen quality

J Assist Reprod Genet. 2019 Feb;36(2):241-253. doi: 10.1007/s10815-018-1350-y. Epub 2018 Oct 31.

Abstract

Purpose: This study was conducted in order to investigate the effects of reactive oxygen species (ROS) levels on the seminal plasma (SP) metabolite milieu and sperm dysfunction.

Methods: Semen specimens of 151 normozoospermic men were analyzed for ROS by chemiluminescence and classified according to seminal ROS levels [in relative light units (RLU)/s/106 sperm]: group 1 (n = 39): low (ROS < 20), group 2 (n = 38): mild (20 ≤ ROS < 40), group 3 (n = 31): moderate (40 ≤ ROS < 60), and group 4 (n = 43): high (ROS ≥ 60). A comprehensive analysis of SP and semen parameters, including conventional semen characteristics, measurement of total antioxidant capacity (TAC), sperm DNA fragmentation index (DFI), chromatin maturation index (CMI), H19-Igf2 methylation status, and untargeted seminal metabolic profiling using nuclear magnetic resonance spectroscopy (1H-NMR), was carried out.

Result(s): The methylation status of H19 and Igf2 was significantly different in specimens with high ROS (P < 0.005). Metabolic fingerprinting of these SP samples showed upregulation of trimethylamine N-oxide (P < 0.001) and downregulations of tryptophan (P < 0.05) and tyrosine/tyrosol (P < 0.01). High ROS significantly reduced total sperm motility (P < 0.05), sperm concentration (P < 0.001), and seminal TAC (P < 0.001) but increased CMI and DFI (P < 0.005). ROS levels have a positive correlation with Igf2 methylation (r = 0.19, P < 0.05), DFI (r = 0.40, P < 0.001), CMI (r = 0.39, P < 0.001), and trimethylamine N-oxide (r = 0.45, P < 0.05) and a negative correlation with H19 methylation (r = - 0.20, P < 0.05), tryptophan (r = - 0.45, P < 0.05), sperm motility (r = - 0.20, P < 0.05), sperm viability (r = - 0.23, P < 0.01), and sperm concentration (r = - 0.30, P < 0.001).

Conclusion(s): Results showed significant correlation between ROS levels and H19-Igf2 gene methylation as well as semen parameters. These findings are critical to identify idiopathic male infertility and its management through assisted reproduction technology (ART).

Keywords: Oxidative stress; Reactive oxygen species; Sperm DNA fragmentation; Sperm DNA methylation; Total antioxidant capacity.

MeSH terms

  • Antioxidants / isolation & purification*
  • Antioxidants / metabolism
  • DNA Fragmentation
  • DNA Methylation / genetics
  • Humans
  • Infertility, Male / genetics*
  • Infertility, Male / metabolism
  • Infertility, Male / pathology
  • Insulin-Like Growth Factor II / genetics*
  • Male
  • Oxidative Stress / genetics
  • RNA, Long Noncoding / genetics*
  • Reactive Oxygen Species / isolation & purification*
  • Reactive Oxygen Species / metabolism
  • Reproductive Techniques, Assisted
  • Semen / metabolism
  • Semen Analysis
  • Sperm Count
  • Sperm Motility / genetics
  • Spermatozoa / growth & development
  • Spermatozoa / metabolism
  • Spermatozoa / pathology

Substances

  • Antioxidants
  • H19 long non-coding RNA
  • IGF2 protein, human
  • RNA, Long Noncoding
  • Reactive Oxygen Species
  • Insulin-Like Growth Factor II