Sperm viability is an important indicator of sperm function evaluation and is associated with plasma membrane integrity. One of plasma membrane main functions is the excretion towards outside and the selection of molecules to pass from outside to inside. A defect in the plasma membrane can easily lead to the death of the sperm. Sperm viability can be assessed by microscopy, image cytometer, flow cytometry using fluorescent dyes. CASA(AndroVision) and flow cytometer(FACS Calibur) used in this study are expensive and highly accurate equipment, but flow cytometer is known to be more expensive and more accurate than CASA.
The purpose of this study was to compare two methods of evaluating sperm survival rates in the equine to find its usefulness
CASA used Hoechst 33342(H33342)/PI dual staining and flow cytometry used CFDA/PI dual staining.
The stain Hoechst 33342 permeates cell membrane and binds specifically to the DNA. All sperm ar marked blue. CFDA is permeable cell membrane. It is transformed into a fluorescent called carboxifluorescein by the esterase of living cells, and show green fluorescence. PI stain only permeates damaged membrane, and show red fluorescence.
The viable rate of spermatozoa with CASA(H33342/PI) and flow cytometry(CFDA/PI) was 84.27±7.55% and 82.91±6.68%, respectively(mean±SD％, n=118).
There was no significant difference in viability of spermatozoa between CASA and flow cytometry(CFDA/PI)(P >0.05). Therefore, CASA is judged to be more cost effective than flow cytometry.