The influence of solubilized porcine zona pellucida protein on the binding capacity of human spermatozoa
The acrosome reaction, sperm-zona pellucida binding, sperm-oolemma binding/fusion and subsequent fertilization are known to be influenced by homologous as well as heterologous follicular fluid and zona pellucida protein. In this study, the effect was investigated of different concentrations of solubilized porcine zona pellucida protein on the zona binding potential of human spermatozoa under hemizona assay conditions. Human spermatozoa incubated with 617 and 142 μg/ml porcine zona pellucida protein showed a statistically significant increase in zona binding when compared with control spermatozoa (106.5 ± 18.0 versus 60.9 ± 29.0, P < 0.02 and 111.0 ± 26.6 versus 63.0 ± 25.5, P < 0.0001, respectively). Concentrations of 67 μg/ml porcine zona pellucida protein did not show a significant increase in zona binding (78.7 ± 21.7 versus 66.7 ± 25.4, P > 0.05). Control zona binding values for different experiments did not differ significantly (60.9 ± 29.0; 63.0 ± 25.5; and 66.7 ± 25.4, P > 0.6). In conclusion, it seems likely that a factor(s) present in the porcine zona pellucida might play a beneficial role during human spermo-ocyte binding. The results of the study might be used in future investigations to manipulate gamete interaction to such an extent that improved fertilization rates can be accomplished.