Nitric oxide induces acrosome reaction in cryopreserved bovine spermatozoa

• Published in: Andrologia Vol. 37; no. 5; pp. 166 - 172
• Main Authors: Rodriguez, P. C., O'Flaherty, C. M., Beconi, M. T., Beorlegui, N. B.
• Format: Journal Article
• Language: English
• Published: Berlin, Germany Blackwell Verlag GmbH 01-10-2005; Blackwell
• Subjects: Acrosome reaction; Acrosome Reaction - drug effects; Animals; Biological and medical sciences; bovine sperm; Catalase - metabolism; Cattle; Cryopreservation; Cyclic AMP-Dependent Protein Kinases - metabolism; Gynecology. Andrology. Obstetrics; Hemoglobins - pharmacology; Male; Male genital diseases; Medical sciences; Methylene Blue - pharmacology; nitric oxide; Nitric Oxide - pharmacology; Nitroprusside - pharmacology; Protein Kinase C - metabolism; Protein Kinase Inhibitors - pharmacology; protein kinases; Protein-Tyrosine Kinases - metabolism; reactive oxygen species; Reactive Oxygen Species - metabolism; Semen Preservation - methods; Spermatozoa - drug effects; Superoxide Dismutase - metabolism; Spermatozoa; Enzyme; Transferases; Ox; Acrosome reaction; EC 2.7.1.37; Germinal cell; Fecundation; Male genital system; Acrosome reaction-bovine sperm-nitric oxide-protein kinases-reactive oxygen species; Vertebrata; Reproduction; Mammalia; Cryopreservation; Protein kinase; Animal; Nitric oxide; Artiodactyla; Ungulata
• ISSN: 0303-4569; 1439-0272
• DOI: 10.1111/j.1439-0272.2005.00674.x

Summary
The aim of this work was to study the effect of nitric oxide on acrosome reaction (AR) and the participation of protein kinases and reactive oxygen species in the AR of cryopreserved bovine spermatozoa. Spermatozoa were capacitated in Tyrode's albumin lactate pyruvate medium with heparin (10 IU ml−1) and then incubated with different concentrations of sodium nitroprusside (SNP) (1–200 μmol l−1). Methylene blue and haemoglobin were used to confirm the role of nitric oxide as an inducer of the AR. The participation of protein kinase A (PKA) , protein kinase C (PKC) and protein tyrosine kinase was evaluated using specific inhibitors of these enzymes (H‐89, 50 μmol l−1; bisindolylmaleimide I, 0.1 μmol l−1 and genistein, 3 μmol l−1). The role of hydrogen peroxide or superoxide anion was evaluated by incubation with catalase or superoxide dismutase respectively. AR percentages were determined by the fluorescence technique with chlortetracycline. The highest levels of AR were obtained in capacitated spermatozoa treated with 5–200 μmol l−1 SNP (24.8 ± 1.8%). The presence of PKA, PKC and protein tyrosine kinase inhibitors likewise decreased AR percentages. The addition of superoxide dismutase had no effect on the AR level but catalase completely blocked it. These results indicate that nitric oxide induces AR in capacitated spermatozoa involving hydrogen peroxide and the participation of PKA, PKC and protein tyrosine kinase as part of the signal transduction mechanism which lead to the AR in cryopreserved bovine spermatozoa.