Resumo

CASAS, E.; MARQUINEZ, A.  e  CORDOBA, M.. Effect of xanthine-xanthine oxidase-catalase system on bovine sperm oxidative metabolism during capacitation induction. InVet [online]. 2016, vol.18, n.2, pp.307-316. ISSN 1668-3498.

The aim of this work was to study the effect of heparin or xanthine-xanthine oxidase-catalase system (superoxide anion generating system) on the induction of capacitation, sperm oxygen uptake, the variation in the activity of creatine kinase-B in bovine spermatozoa and tyrosine kinase and protein kinase C regulation with heparin. Genistein and GF 109203X were used as specific inhibitors of tyrosine kinase and protein kinase C, respectively. Creatine kinase-B activity and lipid peroxidation were registered spectrophotometrically. Oxygen uptake was measured polarographically. Capacitation was evaluated by chlortetracycline technique and viability by trypan blue stain. Data were analyzed by ANOVA and Tukey test. Lipid peroxidation was modified by treatments (P<0.05). In sperm capacitated with heparin the addition of genistein or GF 109203X, provoked a decrease in creatine kinase-B activity, oxygen uptake and capacitation rates (P<0.05). In the presence of xanthine-xanthine oxidase/catalase system, capacitation and oxygen uptake presented a significant decrease at 15 and 45 min compared to heparin treatment but creatine kinase-B activity only presented a decrease at 45 min (P<0.05). To conclude, in cryopreserved bovine spermatozoa heparin capacitation is related to a respiratory burst and a decrease in creatine kinase-B activity, both processes dependent of tyrosine kinase and protein kinase C regulation. Superoxide anion induces sperm capacitation and lipid peroxidation, which can provoke mitochondrial membrane alteration, depending on the incubation time. This deleterious effect may modify the respiratory chain function with a concomitant reduction in creatine kinase-B activity, an enzyme of the cytosol- mitochondria shuttle, not allowing the sperm to reach the energetic state necessary to achieve fertilizing capability.

Palavras-chave : Capacitation; Metabolism; Bovine spermatozoa;; Superoxide anion.