Alleviation of acrosome reaction prematurity by sperm treatment with egg yolk.

OBJECTIVE

To examine the effects of egg yolk on the spontaneous and ionophore-induced acrosome reaction (AR) and sperm-zona pellucida (ZP) binding in spermatozoa from patients with AR prematurity.

DESIGN

Prospective analysis.

SETTING

Private hospital, public research center, and a university-based laboratory.

PATIENTS

In vitro fertilization patients selected on the basis of previous AR testing.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Frequency of the AR, number of ZP-bound spermatozoa.

RESULTS

The pretreatment of spermatozoa with egg yolk decreased the frequency of AR occurring spontaneously during subsequent sperm incubation in capacitating medium but did not modify the sperm response to ionophore. The egg yolk-treated spermatozoa also showed a greater capacity of binding the ZP than their untreated counterparts.

CONCLUSIONS

The pretreatment of spermatozoa with egg yolk alleviates the sperm-ZP binding deficiency resulting from premature initiation of the AR and may be helpful in IVF with patients showing this anomaly.