Ability of spermatozoa to bind to the zona pellucida during oligozoospermia induced with testosterone during a male contraceptive trial.

To determine the ability of spermatozoa to bind to the zona pellucida (ZP) in testosterone-induced oligozoospermia, previously fertile men participating in the World Heath Organization (WHO) male contraceptive trial in Melbourne were studied while oligozoospermic to various degrees. Semen analysis were performed according to WHO methods. One or two ejaculates from each subject were cryopreserved before commencing weekly intramuscular injections of 200 mg testosterone enanthate. The frozen spermatozoa were used as controls for ZP-binding tests of spermatozoa obtained during testosterone-induced oligozoospermia (< 10 x 10(6)/ml) in either the suppression or efficacy (n = 6) and recovery (n = 3) phases. Two other subjects in the recovery phase with normozoospermia were also tested. Human oocytes that failed to fertilized in vitro from infertile patients were used for the sperm-ZP binding test. Control (frozen) spermatozoa were labelled with fluorescein isothiocyanate and test (oligozoospermic semen) spermatozoa were labelled with tetramethylrhodamine B isothiocyanate. A mixture of equal numbers of labelled motile control and test spermatozoa were incubated with 4-6 ZP. There was a significantly (p < 0.01) lower number of spermatozoa bound per ZP in oligozoospermic samples (65 +/- 7, mean +/- SEM) than in controls (80 +/- 7). However, there were still large numbers of spermatozoa bound to the ZP for all the oligozoospermic samples. Five subjects had similar numbers of spermatozoa bound to the ZP for both control and oligozoospermic samples. Overall, the ZP-binding ratio of test and control spermatozoa averaged 0.82 (range 0.51-1.13).(ABSTRACT TRUNCATED AT 250 WORDS)