Importance of sperm-to-epithelial cell contact for the capacitation of human spermatozoa in fallopian tube epithelial cell cocultures.

OBJECTIVE: To investigate the mechanisms involved in the stimulatory effect of fallopian tube epithelial cell coculture on sperm movement characteristics.

DESIGN: Human spermatozoa were cultured with human fallopian tube epithelial cell monolayers. A microporous membrane was used to prevent sperm-to-epithelial cell contact. Sperm movement characteristics were measured at 4 and 24 hours.

SETTING: University hospital and fertility center.

PATIENT(S): Voluntary donors.

INTERVENTION(S): None.

MAIN OUTCOME MEASURE(S): Movement characteristics of human spermatozoa.

RESULT(S): Fallopian tube epithelial cell coculture increased sperm motility, curvilinear velocity, amplitude of lateral head displacement, and hyperactivated motility, mainly at 24 hours, compared with controls. These stimulatory effects were inhibited when a microporous membrane prevented cell-to-cell contact between sperm and fallopian tube epithelial cells.

CONCLUSION(S): Physical contact between sperm and epithelial cells in coculture systems seems to be the main factor in stimulating sperm movement characteristics, and this could be the main mechanism of in vivo sperm capacitation.