| Autor: |
Castiglioni VC; Laboratory of Sperm Biology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil., Siqueira AFP; Laboratory of Sperm Biology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil., Bicudo LC; Laboratory of Sperm Biology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil., de Almeida TG; Laboratory of Sperm Biology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil., Hamilton TRDS; Laboratory of Sperm Biology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil., de Castro LS; Laboratory of Sperm Biology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil., Mendes CM; Laboratory of Sperm Biology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil., Nichi M; Laboratory of Andrology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil., Losano JDA; Laboratory of Andrology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil., Visitin JA; Laboratory of Sperm Biology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil., Assumpção MEODÁ; Laboratory of Sperm Biology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil. |
| Abstrakt: |
Although bovine embryo in vitro production (IVP) is a common assisted reproductive technology, critical points warrant further study, including sperm traits and oxidative status of sperm for in vitro fertilization (IVF). Our aim was to evaluate whether the lipid peroxidation index of commercial bull semen is influenced by sperm traits and oxidative status of sperm populations selected using Percoll® gradient. Semen straws from 48 batches from 14 Nelore bulls were thawed individually, analyzed for motility and subjected to Percoll selection. After Percoll, the lipid peroxidation index of the extender was evaluated, whereas selected sperm were analyzed for motility, acrosome and membrane integrity, mitochondrial membrane potential, chromatin resistance and oxidative potential under IVF conditions. Batches were divided retrospectively in four groups according to lipid peroxidation index. Sperm from Group 4 with the lowest index of lipid peroxidation had, after Percoll selection, greater plasma membrane integrity (81.3%; P = 0.004), higher mitochondrial potential (81.1%; P = 0.009) and lower oxidative potential (135.3 ng thiobarbituric acid reactive substances (TBARS)/ml; P = 0.026) compared with Group 1 with highest lipid peroxidation index (74.3%, 73% and 213.1 ng TBARS/ml, respectively). Furthermore, we observed negative correlations for the lipid peroxidation index with motility, membrane integrity and mitochondrial potential, and positive correlations with oxidative potential. In conclusion, oxidative stress in semen straws, as determined using lipid peroxidation in the extender, is associated with sperm traits and their oxidative potential under IVF conditions. These results provided further insights regarding the importance of preventing oxidative stress during semen handling and cryopreservation, as this could affect sperm selected for IVF. Finally, Percoll selection did not completely remove sperm with oxidative markers. |
