OBJECTIVETo observe the effects of isoflurane combined with diltiazem on human sperm motility in vitro and to investigate its possible mechanism.

METHODSTen normal semen samples were collected, each divided into 9 groups, one as the control and the others treated in vitro with different concentrations of diltiazem or diltiazem +4.2% isoflurane for 1 hour. Sperm motility was observed with the computer-assisted sperm analyzer.

RESULTSCompared with the control, diltiazem significantly decreased sperm motility at the concentrations of 0.01 g/L, 0.04 g/L, 0.2 g/L and 1 g/L in a dose-dependent manner, and reduced it to approximately 0% at 1 g/L. When combined with 4.2% isoflurane, diltiazem obviously increased sperm motility at 0.01 g/L, markedly decreased it at 0.2 g/L, and effected no significant difference at 0.04 g/L and 1 g/L as compared with the corresponding concentrations of diltiazem alone.

CONCLUSIONThe stimulating effect of isoflurane on sperm motility may be associated with the calcium ion channel in sperm. When completely blocked by diltiazem, this effect may turn into an inhibition of sperm motility.