Quantification and identification of sperm subpopulations using computeraided sperm analysis and species-specific cut-off values for swimming speed

Quantification and identification of sperm subpopulations using computeraided sperm analysis and species-specific cut-off values for swimming speed

L Maree, G van der Horst

Department of Medical Bioscience , University of the Western Cape, Private Bag X17, Bellville, 7535 , South Africa

Motility is an essential characteristic of all flagellated spermatozoa and assessment of this parameter is one criterion for most semen or sperm evaluations. Computeraided sperm analysis (CASA) can be used to measure sperm motility more objectively and accurately than manual methods, provided that analysis techniques are standardized. Previous studies have shown that evaluation of sperm subpopulations is more important than analyzing the total motile sperm population alone. We developed a quantitative method to determine cut-off values for swimming speed to identify three sperm subpopulations. We used the Sperm Class Analyzer® (SCA) CASA system to assess the total percentage of motile spermatozoa in a sperm preparation as well as the percentages of rapid, medium and slow swimming spermatozoa for six mammalian species. Curvilinear velocity (VCL) cut-off values were adjusted manually for each species to include 80% rapid, 15% medium and 5% slow swimming spermatozoa. Our results indicate that the same VCL intervals cannot be used for all species to classify spermatozoa according to swimming speed. After VCL intervals were adjusted for each species, three unique sperm subpopulations could be identified. The effects of medical treatments on sperm motility become apparent in changes in the distribution of spermatozoa among the three swimming speed classes.

doi: 10.3109/10520295.2012.757366