Effect of Antioxidants During BovineIn VitroFertilization Procedures on Spermatozoa and Embryo Development

Abstract

Increased amounts of reactive oxygen species (ROS) during in vitro fertilization (IVF) may cause cytotoxic damage to gametes, whereas small amounts of ROS favour sperm capacitation. The aim of this study was to investigate the effect of antioxidants [50 microm beta-mercaptoethanol (beta-ME) and 50 microm cysteamine (Cyst)] or a pro-oxidant (5 mm buthionine sulfoximine) on the quality and penetrability of spermatozoa into bovine oocytes and on the subsequent embryo development and quality when added during IVF. Sperm quality, evaluated by the integrity of plasma and acrosomal membranes, and mitochondrial function, was diminished (p < 0.05) after 4-h culture in the presence of antioxidants. Oocyte penetration rates were similar between treatments (p > 0.05), but antioxidants adversely affected the normal pronuclear formation rates (p < 0.05). The incidence of polyspermy was high for beta-ME (p < 0.05). No differences were observed in cleavage rates between treatments (p > 0.05). However, the developmental rate to the blastocyst stage was adversely affected by Cyst treatment (p < 0.05). The quality of embryos that reached the blastocyst stage, evaluated by total, inner cell mass (ICM) and trophectoderm cell numbers and ICM/total cell ratio was unaffected (p > 0.05) by treatments. The results indicate that ROS play a role in the fertilizing capacity in bovine spermatozoa, as well as in the interaction between the spermatozoa and the oocytes. It can be concluded that supplementation with antioxidants during IVF procedures impairs sperm quality, normal pronuclear formation and embryo development to the blastocyst stage.

Seasonal variation in sperm quality parameters in Swedish red dairy bulls used for artificial insemination

“…These radicals may either be produced endogenously through cellular pathways of the mitochondria and lysosome, or may be induced exogenously in reaction to environmental assaults. Moderate levels of ROS generated by spermatozoa play an important role in normal physiological processes such as sperm capacitation, acrosome reaction, maintenance of fertilizing ability, and stabilization of the mitochondrial capsule in the mid-piece in cattle, the maintenance of a suitable ROS level being, therefore, essential for adequate sperm functionality (Gonçalves et al, 2010). Due to their highly reactive nature, excessive ROS can combine readily with other molecules, directly causing oxidation that can lead to structural and functional changes and result in cellular damage.…”

Use of a colloid to optimize centrifugation in the selection of bovine sperm for IVF

“…As sperm capacitation may be a part of the oxidative process (AITKEN, 1999;O'FLAHERTY et al, 1999;ALI et al, 2003;FUNAHASHI;SANO, 2005), the increase in fertilization rates in the present study can be due to a higher amount of ROS detected in the fertilization medium in the CF group. However, as the antioxidant level of gametes during fertilization seems to be paradoxical, being positive for the surviving of oocytes, but negative or positive for fertilization depending on the balance between the amount of ROS produced and eliminated (BLONDIN et al, 1997;ALI et al, 2003;GONÇALVES et al, 2010), this difference was not sustained when considering only the normal fertilization or the embryonic development.…”

Effect of Glycosaminoglycans on &lt;italic&gt;In vitro&lt;/italic&gt; Fertilizing Ability and &lt;italic&gt;In vitro&lt;/italic&gt; Developmental Potential of Bovine Embryos

“…Previous reports suggest that treatment of sperm with certain reagents during an IVF procedure affects later development of the embryo (Way and Killian, 2006; Kato and Anagao, 2009; Gonçalves et al, 2010), and, additionally, that the pronuclear pattern of the zygote is closely related to blastocyst formation and quality (Ballaban et al, 2001). The higher percent of capacitated or acrosome-reacted sperm in the HP or HA exposed sperm could improve sperm penetration and pronuclear formation.…”