Objective - to examine the possibility of application of flow cytometry to characterize the state of human sperm cells (viability) and the comparison of the results with the light microscopy as a conventional method in andrology. The study used vital dyes that detect damage to the cell membranes: eosin - for light microscopy and propidium iodide - for flow cytometry.

The comparison of cytometry and light microscopy data in the study of sperm cells freshly isolated from ejaculate showed the same number of viable cells was about 35%, indicating that in these conditions, both methods are interchangeable. After incubation of the ejaculate at room temperature for 24 hours flow cytometry detected significant increase in the percentage of dead sperm cells in comparison with light microscopy - 52% and 43% respectively. Similar differences in the comparison of methods were found also after cryopreservation of sperm - cytometry revealed 69% of non-viable sperm, microscopy - 58%. Study of the effects of oxidative stress on sperm using hydrogen peroxide revealed even more significant difference in the sensitivity of the methods: according to the cytometry percentage of non-viable 86%, and microscopy showed only 48%.

Our experiments show the advantages of flow cytometry in study of the viability of sperm cells, especially in case of exposure to ejaculate, because in these conditions, the light microscopy does not adequately reflect the extent of sperm cells damage.