Influence of bovine sperm DNA fragmentation and oxidative stress on early embryo in vitro development outcome

Abstract

Sperm chromatin fragmentation may be caused by a number of factors, the most significant of which is reactive oxygen species. However, little is known about the effect of sperm oxidative stress (OS) on DNA integrity, fertilization, and embryonic development in cattle. Therefore, the goal of this study was to evaluate the influence of sperm OS susceptibility on the DNA fragmentation rate and in vitro embryo production (IVP) in a population of bulls. Groups of cryopreserved sperm samples were divided into four groups, based on their susceptibility to OS (G1, low OS; G2, average OS; G3, high OS; and G4, highest OS). Our results demonstrated that the sperm DNA integrity was compromised in response to increased OS susceptibility. Furthermore, semen samples with lower susceptibility to OS were also less susceptible to DNA damage (G1, 4.06%; G2, 6.09%; G3, 6.19%; and G4, 6.20%). In addition, embryo IVP provided evidence that the embryo cleavage rate decreased as the OS increased (G1, 70.18%; G2, 62.24%; G3, 55.85%; and G4, 50.93%), but no significant difference in the blastocyst rate or the number of blastomeres was observed among the groups. The groups with greater sensitivity to OS were also associated with a greater percentage of apoptotic cells (G1, 2.6%; G2, 2.76%; G3, 5.59%; and G4, 4.49%).In conclusion, we demonstrated that an increased susceptibility to OS compromises sperm DNA integrity and consequently reduces embryo quality.

Protective effects of melatonin on bovine sperm characteristics and subsequent in vitro embryo development

“…For example, sperm that suffer from oxidative stress may incur irreparable physical and chemical modifications, such as lipid peroxidation and antioxidant depletion, which can damage embryonic development (de Castro et al, ). Increased exposure to oxidative stress was reported to compromise sperm DNA integrity, reduce cleavage rate, and increase the number of apoptotic cells in embryos that reached the blastocyst stage (Simoes et al, ; de Castro et al, ). In our experiments, the 10 −3 M melatonin‐dependent improvement in semen characteristics ultimately enhanced development to the blastocyst stage and reduced the number of apoptotic embryonic cells.…”

Induced lipid peroxidation in ram sperm: semen profile, DNA fragmentation and antioxidant status

“…This reaction occurs between 90 and 100 8C at an acidic pH. In brief, one million sperm (diluted in 200 ml PBS) were incubated with 4 mM of ferrous sulfate (50 ml) and 20 mM ascorbate (50 ml) at 37 8C for 1.5 h, as described by Simões et al (2013). Immediately after ROS induction, 600 ml of 10% (v:v) trichloroacetic acids were added to the mixture (2:1) in order to precipitate proteins and cellular debris.…”

Genetic analysis of oocyte and embryo production traits in Guzerá breed donors and their associations with age at first calving

“…Previous studies have investigated nutrition (Ponter et al, 2012;Sales et al, 2015), heat stress (de Torres-Júnior et al, 2008;Baruselli et al, 2012), oocyte quality (Merton et al, 2009), in vitro fertilization (IVF) (Simões et al, 2013), intervals between sessions, and aspiration (Merton et al, 2003) as some of the significant effects that affect the results of IVP. Genetic components have shown to influence the outcome of both MOET (Tonhati et al, 1999;Peixoto et al, 2004;König et al, 2007) and OPU/IVP (Machado et al, 2006;Merton et al, 2009) techniques.…”