OBJECTIVETo investigate the effects of recombinant human testis sperm binding protein (TSBP) on human sperm motility parameters in vitro.

METHODSSperm specimens obtained from 22 healthy fertile men were prepared by the Percoll gradient-centrifugation technique. The sperm suspension was incubated with recombinant His6-TSBP at the concentration of 0.01 mg/ml or 0.1 mg/ml at 37 degrees C for 1 or 3 hours in vitro. The combination of the recombinant protein and sperm membrane was determined by Western blot, and the sperm motility parameters were analyzed by computer-aided sperm analysis (CASA). The same procedure was performed for 12 asthenospermia patients.

RESULTSIn the 22 healthy volunteers, the percentage of forward motile sperm was increased after incubated with 0.1 mg/ml recombinant protein for 1 h (P < 0.05), both forward motile sperm percentage and motility were increased after incubated with recombinant protein at the same concentration for 3 h (P < 0.05), but no effect was observed after incubation with 0.01 mg/ml recombinant protein. In the 12 asthenospermia patients, the forward motile sperm percentage was increased after incubated with 0.1 mg/ml recombinant protein for 3 h (P < 0.05), but no statistically significant difference was observed in sperm motility.

CONCLUSIONRecombinant His6-TSBP at the concentration of 0.1 mg/ml can increase sperm motility in healthy fertile men and the forward motile sperm percentage in both healthy fertile men and asthenospermia patients in vitro.