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 characterist ics. Design: Human spermatozoa were cultured with human fallopian tube epithelia l cell monolayers. A microporous membrane was used to prevent sperm-to-epit helial 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 motilit y, curvilinear velocity, amplitude of lateral head displacement, and hypera ctivated motility, mainly at 14 hours, compared with controls. These stimul atory 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 cocul ture systems seems to he the main factor in stimulating sperm movement char acteristics, and this could be the main mechanism of in vivo sperm capacita tion. (Fertil Steril (R) 2000;74:780-4. (C) 2000 by American Society for Re productive Medicine.).