A time course study of capacitation and the acrosome reaction in human spermatozoa using a revised chlortetracycline pattern classification.

OBJECTIVE

To study the time course of capacitation, spontaneous, and A23187-induced acrosome reaction of human spermatozoa during 8 hours incubation in vitro using the chlortetracycline (CTC) assay with a revised fluorescent pattern classification.

DESIGN

Fertile donor spermatozoa were isolated by direct swim-up and incubated in Earle's balanced salt solution for up to 8 hours. At hourly intervals, spermatozoa were stained with CTC before and after the addition of A23187 to induce the acrosome reaction.

SETTING

The University Clinic, Jessop Hospital for Women, Sheffield, United Kingdom.

PATIENTS

Donors participating in the Donor Insemination Program.

MAIN OUTCOME MEASURES

Eight fluorescent patterns identified by the CTC assay and acrosome-reacted spermatozoa detected by indirect immunofluorescence using 18.6 monoclonal antibody.

RESULTS

Using a statistical model defined by analysis of deviance allowed rationalization of the CTC pattern classification by grouping together patterns that showed a similar and significant change over time. In addition, spontaneous and A23187-induced acrosome-reacted spermatozoa identified by the CTC assay were shown to be correlated significantly to those identified by indirect immunofluorescence.

CONCLUSION

The CTC assay using a revised pattern classification offers a more precise description of human spermatozoa capacitation in vitro. Also, CTC-identified acrosome reaction (both spontaneous and A23187 induced) was confirmed independently by indirect immunofluorescence.