OBJECTIVETo explore the influence of Candida albicans (Ca) on the motility and ultrastructure of human spermatozoa and its possible mechanism.

METHODSSemen samples obtained from 10 healthy volunteers by masturbation were prepared by the swim-up technique and sperm density to 40 x 10(6)/ml. The samples were then inoculated at 37 degrees C with different concentrations of a uropathogenic strain of Ca isolated from an outpatient, with initial fungi/spermatozoa ratios varying among 1:1 (Group A), 1:10 (Group B), 1:100 (Group C), 1:1000(Group D), and 1:10,000 (Group E). And Group F containing Ham's F-10 only was found as the negative control. Motion parameters were analysed by computer-aided sperm analyzer (CASA) at 0 hour, 1 hour, 2 hours and 4 hours respectively. Modalities of spermatozoa and possible adherence and/or agglutination were observed under the light microscope. Finally, all the samples were studied by transmission electron microscopy.

RESULTSDistinct adhesion of spermatozoa to Ca and agglutination were noticed. In all the motion parameters, progressive motility was affected most and dependent upon incubation time and bacterial concentration. Progressive motility showed a significant difference between Group A and the control (P < 0.01). With the prolongation of incubation time, other parameters were showing more and more differences. Analysis by electron microscopy revealed multiple ultrastructural damages.

CONCLUSIONCa significantly inhibits human sperm motility and decreases sperm viability in vitro. Its mechanism is possibly related to Ca's adhesion to human spermatozoa and the impairment inflicted by Ca to sperm ultrastructure.