FIG. 5.

Percentage of acrosome reactions of Fyn-null sperm following capacitation in vitro is shown. Fyn-null and WT mice (five males in each group) were used to isolate epididymal sperm. Isolated sperm were incubated for 90 min in capacitating medium containing 25 mM NaHCO₃ and 4 mg/ml BSA in the absence (no induction) or presence (induction) of 10 μM calcium ionophore A23187 to test sperm acrosome reaction. Flow cytometric analysis (20 000 events per sample) was performed after live sperm were stained with PNA-FITC and PI. The mean ± SD incidence of PNA-FITC-positive but PI-negative (representing those sperm that had successfully undergone acrosome reaction) Fyn-null sperm was compared with that of WT sperm. Asterisk indicates significant difference (P < 0.05).