Sperm interaction with fallopian tube apical membrane enhances sperm motility and delays capacitation.

OBJECTIVE: To understand the effect of sperm contact with the apical plasma membrane of tubal epithelial cells on sperm motility, velocity, and capacitation. DESIGN: Prospective, controlled in vitro study. SETTING: University medical center. PATIENT(S): Women of reproductive age undergoing hysterectomy for benign gynecologic indications and normozoospermic donors of proved fertility. MAIN OUTCOME MEASURE(S): Sperm motility as measured manually, velocity as measured by computer-assisted sperm motility analysis, and capacitation status as measured by the chlortetracycline fluorescence assay. RESULT(S): Sperm incubated with apical membrane vesicles had a significantly higher motility at 12 (87.4% +/- 3.4% versus 69.2% +/- 4.8% [mean +/- SEM]), 24 (85.2% +/- 3.1% versus 60.5% +/- 7.2%) and 48 hours (78.9% +/- 5.3% versus 42.4% +/- 11.3%) compared with control (sperm incubated with human tubal fluid media in the absence of apical membrane vesicles) (n = 4). Progressive velocity was significantly higher at 12 (78.2 +/- 1.4 versus 61.7 +/- 16.1 microns/s) and 24 (66.2 +/- 3.9 versus 34.4 +/- 9.8 microns/s) hours (n = 4). Incubation with apical membrane vesicles significantly slowed the transition from uncapacitated to capacitated chlortetracycline fluorescence pattern (n = 5). CONCLUSION(S): Contact with the apical plasma membrane of tubal epithelial cells enhances sperm motility and delays sperm capacitation in vitro.