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Updated: May 14, 2026
Flow Cytometric Analysis of Biomarkers for Detecting Human Sperm Functional Defects
Published on: April 21, 2022
Flow cytometric characterization of apoptosis and chromatin damage in spermatozoa
Howard H Kim1, Michael Funaro, Svetlana Mazel
1Departments of Urology and Reproductive Medicine, Weill Cornell Medical College, New York, NY 10065, USA.
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.
Insights
Apoptosis in human sperm may occur via the mitochondrial pathway. Researchers observed a decrease in mitochondrial potential before changes in membrane phospholipids, suggesting this route is activated first.
Area of Science:
- Reproductive Biology
- Cell Biology
- Biochemistry
Background:
- Sperm chromatin damage is linked to apoptosis, but the specific pathway (cytoplasmic vs. mitochondrial) remains unclear.
- Human sperm possess minimal cytoplasm but abundant mitochondria, suggesting a potential role for mitochondria in apoptosis.
Purpose of the Study:
- To investigate the activation pathway of apoptosis in human spermatozoa.
- To determine whether apoptosis in sperm initiates through cytoplasmic or mitochondrial routes.
Main Methods:
- Multichannel flow cytometry was employed to analyze apoptosis markers in human sperm.
- Specific probes including propidium iodide (PI), annexin V (AV), DiIC1(5), and a proprietary fluorochrome (PF-1) were utilized.
Main Results:
- A time-dependent increase in staining with annexin V (AV) and the proprietary fluorochrome (PF-1) was observed.
- Concurrent with AV and PF-1 staining, a decrease in mitochondrial potential, indicated by reduced DiIC1(5) staining, was detected.
- The observed decrease in mitochondrial potential preceded alterations in sperm membrane phospholipids.
Conclusions:
- The findings strongly suggest that apoptosis in human spermatozoa is activated through the mitochondrial pathway.
- The drop in mitochondrial potential appears to be an early event in sperm apoptosis, preceding membrane phospholipid changes.
