Impact of Meditation and Yoga on Oxidative DNA Damage in Sperm: ClinicalImplications

The generation of excessive reactive oxygen species (ROS) leads to the disruption of cellular homeostasis, a condition known as Oxidative Stress (OS). There is damage caused to almost all biomolecules like carbohydrates, lipids, proteins and even nucleic acids by several ways like programmed cell death with apoptosis, autophagy and the promotion of aging dependent processes. Free radicals subserve numerous functions at physiological levels; however supraphysiological levels are detrimental to all biomolecules and several redox dependent reactions. Almost every cell (both somatic and germ cells) is targeted by free radicals. However, the sperm is most vulnerable to OS. The uniqueness of sperm, a highly polarized cell, lies in its morphology, chromatin structure and function, characterized by a myriad of changes which occur during spermatogenesis and spermiogenesis. Human sperm chromatin is relatively less compact as it retains 5–15% of histones in comparison to other mammalian species like bulls, stallions, hamsters, and mice, which retain <5% of histones. To aid in its functions, it assumes hydrodynamic shape post spermiogenesis and loses majority of its cytoplasm. This results in loss of majority of its antioxidants and compaction of sperm nucleus to a size 1/6th to 1/20th to that of somatic cell. Due to this highly compact chromatin sperm assumes a relatively transcriptionally and translationally inert state. But, Ioannou et al. reported the epigenetic role for the retained histones as the peripheral histone bound nucleosome complex remains transcriptionally active and susceptible to the environmental insult [1]. The contribution of sperm to embryonic development is frequently overlooked and is considered to be quiescent, whose only function is thought to be mere a delivery vehicle of the paternal genome to the oocyte. But oxidative damage to sperm DNA disrupts the integrity of its DNA and RNA so limits not only its fertilizing potential but also adversely affects development potential of embryo through dysregulation of sperm transcripts.