Lipid peroxidation and generation of hydrogen peroxide in frozen-thawed ram semen supplemented with catalase or Trolox

Semen manipulation and cryopreservation-thaw procedures may accelerate the generation of reactive oxygen species (ROS). Sperm exposure to large amounts of ROS has been shown to cause membrane lipid peroxidation and cellular injury to the sperm. The objective of this study was to overcome the ROS production in frozen-thawed ram semen by the addition of the antioxidants catalase or Trolox to semen following thawing. Frozen-thawed ram semen (100 x 10(6) sperm/straw) was supplemented with PBS (control group), 100 mu g/ml catalase, or 100 mu M Trolox/10(8) sperm (catalase and Trolox being dissolved in PBS) and incubated (37 degrees C) for 5 min. Under the experimental conditions used in this study, the catalase and Trolox antioxidants failed to protect the sperm from the spontaneous production of ROS. However, when lipid peroxidation was induced by iron (FeSO(4)), the addition of Trolox promoted a reduction (P < 0.05) in the formation of TBARS in the semen, compared to the control and catalase semen samples. The generation of TBARS and H(2)O(2) occurred in the extender alone, without the presence of sperm cells. In conclusion, the addition of Trolox to frozen-thawed ram semen could be beneficial as it decreases the production of TBARS when oxidative stress is induced. It is possible that a longer incubation period could lead to different results. The concentration of catalase also needs to be further evaluated. The extender could contribute to the oxidative stress of sperm, as it is a source of ROS during the cryopreservation of semen. (C) 2010 Elsevier B.V. All rights reserved.

Lipid peroxidation and generation of hydrogen peroxide in frozen-thawed ram semen cryopreserved in extenders with antioxidants

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Trehalose and a calcium chelator for ram semen cryopreservation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Motility and viability of ram sperm cryopreserved in a Tris-egg yolk extender supplemented with anti-oxidants

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Viabilidade e capacitação espermáticas, geração de peróxido de hidrogênio(H2O2) e lipoperoxidação no sêmen ovino adicionado de plasma seminal ou antioxidante após a criopreservação

Pós-graduação em Medicina Veterinária - FMVZ

Viabilidade e fertilidade de sêmen ovino criopreservado com glicerol e dimetilacetamida acrescido de trealose EDTA

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Integridade e funcionalidade dos espermatozóides ovinos submetidos à criopreservação após a incorporação de colesterol, desmosterol, ácido oléico-linoléico e alfa-lactoalbumina

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Variabilidade das sub-populações de espermatozóides avaliados pela cinética em sistema computadorizado e combinação de sondas fluorescentes como praâmetro quantitativo do sêmen congelado de ovinos

Pós-graduação em Medicina Veterinária - FMVZ

Avanços na criopreservação do sêmen ovino I: diluidores e crioprotetores

The effectiveness of using frozen sheep semen in artificial insemination programs requires the development of extenders and freezing protocols that will increase pregnancy rate of inseminated females. This work aimed to survey the main extenders, additives and external and internal cryoprotectants that have been employed to improve the maintenance levels of sperm parameters after the freezing-thawing process. Better rates of post-thawing sheep sperm viability may be obtained with changes in the freezing extender composition, whether by the adjustment of its components or by introducing additives that inhibit the occurrence of sperm changes during the cryopreservation process. Thus, the possible changes proposed must take into consideration the intrinsic characteristics of ram semen and the individual variability among animals. It is important to emphasize that the sperm cryopreservation effectiveness requires that all process steps are conducted in an integrated manner, to maximize the fertility rate of frozen ram semen.

Centrifugação de espermatozóides ovinos em gradiente de densidade contínuo: efeito sobre a taxa de prenhez e proporção do sexo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)