Nitric oxide and superoxide anion production during heparin-induced capacitation in cryopreserved bovine spermatozoa

RODRIGUEZ PC; VALDEZ LB; ZAOBORNYJ T; BOVERIS A; BECONI MT

REPRODUCTION IN DOMESTIC ANIMALS (1990)

WILEY-BLACKWELL PUBLISHING, INC

Año: 2011 vol. 46 p. 74 - 81

0936-6768

The aim of this work was to quantify NO, O2- and ONOO- production during heparin-induced capacitation of cryopreserved bovine spermatozoa. A time dependent hyperbolic increase was observed for heparin-dependent capacitation, O2 uptake, and NO production. Conversely, O2- production was increased during the first 15 min of incubation, showing a decrease from this time until 45 min. At 15 min of heparin incubation, a three-fold increase in O2 consumption (5.9 ± 0.6 nmol/min.107 cells), an enhancement in NO release (1.1 ± 0.2 nmol/min.107 cells), and a five-fold increase in O2- production (1.3 ± 0.07 nmol/min.107 cells), as compared to non-capacitated spermatozoa, were observed. Peroxynitrite production rate was estimated at 15 min of sperm capacitation taking into account NO and O2- generation and the second-order rate constant of the reaction between these species (k1= 1.9 x 1010 M-1 s-1). This value results about 4 x 10-8 M s-1. To conclude, heparin-induced capacitation of cryopreserved bovine spermatozoa enhances NO and O2- production, generating an increase in ONOO- production. These products are released to the extracellular space and are likely involved in the process of sperm capacitation.