Effect of different concentrations of heparin on canine sperm capacitation in vitro

Capacitation is an important process in the sperm maturation and it is an obligatory previous step to the fertilization. The heparin (HE) induces in vitro sperm capacitation in bovine, goat and equine. The objective of this study was to evaluate in vitro the HE activity in different concentrations on the sperm capacitation in canine. Sperm from four adults canines adults (German Shepherd, ages between 2 and 4 years old) were incubated in different HE concentrations (5, 10, 25 and 50 mu g/mL) up to 4 hours. Sperm capacitation and acrosome reaction were determined by of Chlortetracycline-Hoechst 33258 (CTC-HO) stain. The results did not show any significant differences (P > 0.05) between groups, in the percentage of capacitated-acrosome-intact sperm (C pattern) in the different incubation times. Nevertheless the addition of 50 mu g/mL HE to the capacitating medium increased significantly (P < 0.05) the percentages of acrosome reaction (RA pattern) from 3 h of incubation. Different HE concentrations used, didn't have any additional effect on the percentage of viability and sperm motility. These results suggest that the addition of 50 mu g/mL of HE to the capacitating medium (mCCM) increases (P < 0.05) the percentages of RA from 3 h of incubation.