Chemoattractant agents and nerve growth factor stimulate human spermatozoal reactive oxygen species generation.

OBJECTIVE

To investigate the ability of N-formyl-methionyl-leucyl-phenylalanine (f-MLP), complement 5a (C5a), and nerve growth factor (NGF) to stimulate human spermatozoal reactive oxygen species generation in fertile and infertile patients.

DESIGN

Prospective, controlled study measuring human spermatozoal reactive oxygen species generation after addition of f-MLP, C5a, or NGF.

SETTING

A large health maintenance organization.

PATIENTS, PARTICIPANTS: The fertile group consisted of 14 men with established fertility and normal bulk semen parameters. The infertile group was comprised of 8 men who were infertile after > 18 months of unprotected sexual intercourse.

INTERVENTIONS

The sperm samples were subjected to four test conditions: f-MLP stimulation, C5a stimulation, NGF stimulation, and no stimulation (control).

MAIN OUTCOME MEASURE

Reactive oxygen generation was measured over a 15-minute period using the method of chemiluminescence.

RESULTS

In both the fertile and infertile groups, reactive oxygen species generation was significantly enhanced by f-MLP, C5a, and NGF compared with controls. No significant difference in f-MLP- and C5a-stimulated reactive oxygen production was demonstrated between the infertile and fertile groups; however, there was a significant difference in reactive oxygen generation between infertile and fertile subjects when stimulated with NGF.

CONCLUSIONS

The current study represents the first report of f-MLP-, C5a-, and NGF-stimulated reactive oxygen species generation by human spermatozoa. Nerve growth factor enhanced reactive oxygen species production to a greater extent in infertile subjects compared with fertile subjects. This points to a possible NGF-mediated biochemical defect in the sperm of infertile patients.