Objective: To study effects of cadmium on rat sperm motility evaluated with computer assisted sperm analysis.
Methods: Different doses of cadmium chloride (0.2, 0.4, 0.8 mg Cd/kg BW) were administrated i.p. to adult male Sprague-Dawley rats. Control animals received the same volume of 0.9% NaCl solution. After 7 days, the rats were sacrificed with their testes removed. A part of one testis was used for testicular sperm head counts and daily sperm production observation. The motility of spermatozoa obtained from cauda epididymides using the "diffusion" method was measured by computer assisted sperm analysis (CASA).
Results: The sperm head counts and daily sperm production decreased significantly in the high dose group. The motility of spermatozoa in the middle dose group was reduced significantly. No motile sperm was found in the high dose group. The results suggest that germinal epithelium was impaired irreversibly in a short time to produce toxic effects on spermatogenesis at high cadmium doses.
Conclusion: Cadmium may reduce sperm motility at a dose far below the dose affecting sperm production at this time point. The motility of sperm is an early and sensitive endpoint for the assessment of cadmium toxicity on male reproduction.