Abstract
This study investigated the mechanisms of the stimulatory effect of hyaluronic acid on motility in human sperm in vitro. A method, involving the measurement of forward progression through an agarose gel, was used to measure sperm motility quantitatively. Changes in intracellular Ca 2+ concentrations in sperm were detected using the fluorescent dye Fluo-3. The effects of hyaluronic acid (6.5, 65, 650 ng/mL) and nifedipine (32 nM) on sperm motility were investigated. The effects of hyaluronic acid, nifedipine (32 nM), A23187 (32 µM), and a monoclonal antibody to human CD44 (1 µg/mL) on changes in intracellular CA 2+ concentrations were investigated. Hyaluronic acid significantly ( p <. 008) stimulated sperm motility and this was partially inhibited by nifedipine.A23187 significantly ( p <. 005) increased intracellular CA 2+ concentrations. Hyaluronic acid significantly ( p <. 04) increased intracellular Ca 2+ concentrations and this was inhibited by nifedipine and a monoclonal antibody to human CD44. Hyaluronic acid stimulated human sperm motility by increasing intracellular Ca 2+ concentration, partially via an influx of extracellular Ca 2+.