Utilization of a computer-assisted sperm motion analysis system to examine effects of dinoseb on rat sperm

The computer-assisted sperm motion analysis (CASA) system has been used as one of the useful means for reproductive toxicity studies in male animals. Since various parameters of sperm motility are measured by the CASA system, we investigated the effects of a herbicide dinoseb, a testicular toxicant, and which parameter was the most appropriate for detecting changes. Crj:CD(SD)IGS mature male rats were administered dinoseb at a dose of 0 (corn oil), 5 or 7.5 mg/kg for 3 consecutive days, and were necropsied for cauda epididymal sperm analysis after a 12-day (Day15) or 19-day (Day 22) withdrawal period (Experiment I). No sperm motility parameters of dinoseb-treated rats were changed on Day 15, but on Day 22, the percentage of motile sperm (MOT) was significantly decreased in rats treated with dinoseb at 7.5 mg/kg. Other parameters, such as path velocity (VAP), curvilinear velocity (VCL), and amplitude of lateral head displacement (ALH) were significantly decreased as well. In Experiment II, no parameters of sperm motility showed any change in rats treated with dinoseb at 7.5 mg/kg three times per week when evaluated on Day 21. It was concluded that MOT, VAP, VCL, and ALH were more sensitive to dinoseb effects on sperm in the CASA system.