However, treating of sperm with high level CLC (2.5 mg and
3.0 mg) caused sharp decrease of post-thaw spermatologic values.
Moreover, high concentrations (2.5 mg and 3.0 mg) of cholesterolloaded
cyclodextrin in the extender was toxic and decreased postthaw
sperm motility, duration of motility, viability, and fertilization
rates (Tables 1 and 2). The reduction of these sperm quality
parameters was likely due to the high viscosity of cholesterol in
extender. It is also pointed out that high concentrations of membrane-
stabilizing compounds increased viscosity of extenders and
suggested that particular debris in the extender could reduce
post-thaw sperm motility and fertility rates