Cryopreservation-induced human sperm DNA damage is predominantly mediated by oxidative stress rather than apoptosis

Abstract

Human sperm DNA fragmentation is associated with an increase in oxidative stress during cryopreservation, rather than the activation of caspases and apoptosis. The estrogenic compound genistein may be useful in reducing this effect but larger trials are needed to confirm this.

Effect of genistein supplementation of thawing medium on characteristics of frozen human spermatozoa

“…The lower DNA damage observed following supplementation of the thawing medium with genistein suggests that ROS generation and redox balance are the most important factors responsible for the disruption of the condensation and stability of sperm chromatin after cryopreservation [40]. Recently, Thomson et al [41] reported that addition of 50 µmol L -1 and 100 µmol L -1 of genistein to the cryoprotectant had a significant protective effect on sperm DNA using TUNEL and 8OHdG as a biomarker of oxidative stress and they also reported a significant Numbers with different superscripts differ significantly within the columns (P < 0.05). npg increase in motility and viability.…”

“…npg increase in motility and viability. These authors concluded that human sperm DNA fragmentation is associated with an increase in oxidative stress during cryopreservation, rather than the activation of caspases and apoptosis [41].…”

Sperm preparation before freezing improves sperm motility and reduces apoptosis in post-freezing-thawing sperm compared with post-thawing sperm preparation

“…The negative effects relating to rapid decreases in temperature, such as osmotic injury, cellular dehydration, intra-cellular ice crystal formation, and oxidative stress, also lead to damage to sperm DNA, chromatin instability and DNA denaturation [4][5][6][7][8]. Therefore, the reproductive outcome following fertilization with the sperm containing the damaged genetic material may be poor [8][9][10].…”

“…For sperm cryopreservation, several factors, such as the pre-frozen sperm quality baseline, freezing and thawing method, and cryopreservative medium, and volume of cryopreserved specimen, have been previously demonstrated to be the crucial factors relating to post-thawing sperm outcome [2,7,21,23,24]. Several attempts have been made to improve cryopreservation techniques and media, leading to the improvement of cryopreservation [6,21,22,25]. Notably, the quality of ejaculated semen is also related to the outcome of cryopreservation.…”

“…Notably, the quality of ejaculated semen is also related to the outcome of cryopreservation. For example, dead spermatozoa or leukocytes in pre-freezing semen detrimentally affect the sperm survival rate and the fertility potential after thawing through the ROS generation process [6]. A number of studies have demonstrated that supplemental addition of antioxidative to cryoprotective medium, e.g., ascorbate or catalase, minimize DNA damage and preserve sperm integrity; however, the benefit of these supplementations is still debated [25,26].…”