Flow cytometric characterization of apoptosis and chromatin damage in spermatozoa.

ABSTRACT

Apoptosis has been implicated in sperm chromatin damage; it is unclear whether apoptosis occurs through cytoplasmic or mitochondrial pathways. Sperm has minimal volume of cytoplasm but prominent mitochondria. Propidium iodide (PI), annexin V (AV), DiIC1(5) and proprietary fluorochrome (PF-1) were used to investigate apoptosis activation in human sperm using multichannel flow cytometry. There was a time-dependent increase in staining of spermatozoa with both AV and PF-1 and decrease in mitochondrial staining with DiIC1(5). These results strongly suggest that the drop in mitochondrial potential precedes changes in membrane phospholipids, and thus suggest apoptotic activation through mitochondrial pathway in human spermatozoa.