לקיחת טבליות סיראן או ראונק

להלן שני מאמרים בנושא זרע וחומרים אלו היכולים להצביע על שימור ושיפור התנועתיות של הזרע בנוכחות חומר זה או דומיו Biol Reprod. 2012 Nov 8;87(5):110. doi: 10.1095/biolreprod.112.102020. Print 2012 Nov. Sperm motility is lost in vitro as a consequence of mitochondrial free radical production and the generation of electrophilic aldehydes but can be significantly rescued by the presence of nucleophilic thiols. Aitken RJ1, Gibb Z, Mitchell LA, Lambourne SR, Connaughton HS, De Iuliis GN. Author information • 1Priority Research Centre for Reproductive Science, Discipline of Biological Sciences, University of Newcastle, Callaghan, New South Wales, Australia. [email protected] Abstract The prolonged incubation of human spermatozoa in vitro was found to induce a loss of motility associated with the activation of mitochondrial reactive oxygen species generation in the absence of any change in mitochondrial membrane potential. The increase in mitochondrial free radical production was paralleled by a loss of protein thiols and a concomitant rise in the formation of 4-hydroxynonenal, an electrophilic product of lipid peroxidation that was found to directly suppress sperm movement. These results prompted a search for nucleophiles that could counteract the action of such cytotoxic aldehydes, as a means of ensuring the long-term survival of spermatozoa in vitro. Four nucleophilic compounds were consequently assessed (penicillamine, homocysteine, N-acetylcysteine, and mercaptosuccinate) in three species (human, rat, and horse). The results of this analysis revealed drug and species specificity in the manner in which these compounds affected sperm function, with penicillamine conferring the most consistent, effective support. This prosurvival effect was achieved downstream of mitochondrial reactive oxygen species generation and was associated with the stabilization of 4-hydroxynonenal generation, the preservation of sperm thiols, and a reduction in 8-hydroxy-2'-deoxyguanosine formation. Theoretical calculations of Fe-S and Cu-S bond distances and corresponding binding energies suggested that the particular effectiveness of penicillamine may, in part, reflect the ability of this nucleophile to form stable complexes with transition metals that catalyze lipid peroxidation. The practical implications of these findings were indicated by the effective preservation of equine spermatozoa for 8 days at ambient temperature when the culture medium was supplemented with penicillamine . The effect of cysteine and superoxide dismutase on the quality of post-thawed chicken sperm. Partyka A1, Ni&#380;a&#324;ski W, Bajzert J, &#321;ukaszewicz E, Ochota M. Author information • 1Wroclaw University of Environmental and Life Sciences, Faculty of Veterinary Medicine, Department of Reproduction and Clinic of Farm Animals, pl. Grunwaldzki 49, 50-366 Wroc&#322;aw, Poland. Electronic address: [email protected]. Abstract The study was conducted to determine the influence of N-acetyl-l-cysteine (NAC) and superoxide dismutase (SOD) on chicken sperm motility, plasma membrane and acrosome integrity, mitochondrial activity, lipid peroxidation (LPO) and apoptotic changes after freezing-thawing process. Semen samples from fifteen Greenlegged Partridge roosters were pooled, diluted with EK extender without antioxidants (control), or supplemented with 5 mM NAC, or 200 U/mL SOD. Samples were subjected to cryopreservation. After thawing, sperm parameters evaluated by using CASA system and flow cytometry were assessed. The extender supplemented with NAC and SOD caused the increase (P < 0.01) in sperm motility and provided the higher percentage of rapid sperm (P < 0.01) compared to control. The addition of NAC increased the progressive motility of cells (P < 0.01). In NAC and SOD groups post-thaw plasma membrane integrity was higher (P < 0.05) and less spermatozoa showed apoptotic changes (P < 0.01, P < 0.05). Post-thaw percentage of sperm with high mitochondrial activity was the greatest (P < 0.05) with NAC addition. The SOD supplementation only reduced (P < 0.05) the percentage of sperm with LPO, following the cryopreservation. These results indicate that the addition of NAC (5 mM) and SOD (200 U/mL) is beneficial for the function of frozen-thawed chicken spermatozoa. The antioxidants prevented the reduction in motility, viability and mitochondrial membrane potential, as well as protected from apoptotic changes in sperm. Lipid peroxidation in sperm plasma membrane was decreased by SOD supplementation. Therefore, these antioxidants can be recommended as an additional component of chicken freezing extender. Copyright © 2013 Elsevier Inc. All rights reserved.