title: Oocyte quality determines bovine embryo development after fertilisation with hydrogen peroxide-stressed spermatozoa.
abstract: Exposure of gametes to specific stressors at sublethal levels can enhance the gametes' subsequent performance in processes such as cryopreservation. In the present study, bull spermatozoa were subjected to H₂O₂ for 4 h at 100-, 200- and 500-μM levels; computer-assisted sperm analysis (CASA) and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) assay were used for evaluation of subsequent sperm motility and DNA integrity, respectively. Exposure of spermatozoa to H₂O₂ did not affect sperm motility but DNA integrity was negatively affected by 500 μM H₂O₂ compared with mock-exposed spermatozoa, whereas both motility and DNA integrity were affected compared with untreated spermatozoa. Nevertheless, insemination of oocytes with spermatozoa exposed to 200 μM H₂O₂ increased fertilisation, cleavage and blastocyst rates (P < 0.05). Furthermore, the higher blastocyst yield after fertilisation of oocytes with spermatozoa exposed to 200 μM H₂O₂ was related to oocyte diameter, with large-medium oocytes yielding higher blastocyst rates, while small-diameter oocytes consistently failed to develop into blastocysts. In conclusion, the results indicate that exposure of spermatozoa to 200 μM H₂O₂ before sperm-oocyte interaction may enhance in vitro embryo production in cattle. However, this increased embryo production is largely dependent on the intrinsic quality of the oocytes.
authors.affiliation: Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium. mohammadbozlur.rahman@ugent.be
authors.forename: Mohammad Bozlur
authors.initials: MB
authors.lastname: Rahman
authors.forename: Leen
authors.initials: L
authors.lastname: Vandaele
authors.forename: Tom
authors.initials: T
authors.lastname: Rijsselaere
authors.forename: Mahdi
authors.initials: M
authors.lastname: Zhandi
authors.forename: Dominiek
authors.initials: D
authors.lastname: Maes
authors.forename: Mohammed
authors.initials: M
authors.lastname: Shamsuddin
authors.forename: Ann
authors.initials: A
authors.lastname: Van Soom
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001755:Blastocyst / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D002417:Cattle / Q000502:physiology*; D048429:Cell Size; D053938:DNA Fragmentation / Q000187:drug effects; D004477:Ectogenesis; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary; D006861:Hydrogen Peroxide / Q000009:adverse effects / Q000494:pharmacology*; D007091:Image Processing, Computer-Assisted; D008297:Male; D009865:Oocytes / Q000166:cytology / Q000502:physiology*; D009866:Oogenesis; D009994:Osmolar Concentration; D016877:Oxidants / Q000009:adverse effects / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects*; D013081:Sperm Motility / Q000187:drug effects; D013084:Sperm-Ovum Interactions / Q000187:drug effects; D013094:Spermatozoa / Q000187:drug effects* / Q000502:physiology
chemical_list: D016877:Oxidants; D006861:Hydrogen Peroxide