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Updated: Aug 8, 2026
Mouse Sperm Cryopreservation and Recovery using the I·Cryo Kit
Published on: December 12, 2011
Magnetic-activated cell sorting before cryopreservation preserves mitochondrial integrity in human spermatozoa
Sonja Grunewald1, Uwe Paasch, Tamer M Said
1Department of Dermatology/Andrology Unit, University of Leipzig, Germany.
Abstract:
Superparamagnetic annexin-V conjugated microbeads are able to eliminate spermatozoa with externalized phosphatidylserine, a membrane feature of apoptotic cells as well as spermatozoa with deteriorated plasma membrane. Our objective was to evaluate the effects of annexin-V Magnetic-Activated Cell Sorting (MACS) in cryopreservation-thawing protocols and on integrity of sperm mitochondrial transmembrane potential and mitochondrial integrity survival rate (MSR). Mature spermatozoa of 10 healthy donors were prepared by density gradient centrifugation and divided into 2 aliquots afterwards. The first one was subjected to annexin-V MACS followed by cryopreservation and thawing, while the second was cryopreserved-thawed without MACS to serve as control. Annexin-negative sperm separated by MACS showed significantly higher levels of intact mitochondria following cryopreservation-thawing (45.4+/-8.6%) compared to sperm that were not separated (15.8+/-4.6%, p<0.01). Separating a distinctive population of non-apoptotic spermatozoa with intact membranes may optimize cryopreservation-thawing outcome. MACS using annexin-V microbeads enhances the percentage of spermatozoa with intact transmembrane mitochondrial potential and mitochondrial integrity survival rates following cryopreservation.
Insights
Annexin-V Magnetic-Activated Cell Sorting (MACS) effectively removes damaged sperm before cryopreservation. This technique significantly improves the mitochondrial integrity and survival rate of sperm after thawing, enhancing sperm quality for assisted reproduction.
Area of Science:
- Reproductive Biology
- Cell Biology
- Cryobiology
Background:
- Spermatozoa with externalized phosphatidylserine indicate apoptosis or membrane damage.
- Cryopreservation-thawing protocols can compromise sperm mitochondrial integrity.
- Improving sperm quality post-cryopreservation is crucial for assisted reproductive technologies.
Purpose of the Study:
- To evaluate the impact of annexin-V Magnetic-Activated Cell Sorting (MACS) on sperm cryopreservation and thawing.
- To assess the effect of MACS on sperm mitochondrial transmembrane potential and mitochondrial integrity survival rate (MSR).
Main Methods:
- Spermatozoa from 10 healthy donors were prepared using density gradient centrifugation.
- One aliquot underwent annexin-V MACS before cryopreservation and thawing.
- The second aliquot served as a control, undergoing cryopreservation and thawing without MACS.
Main Results:
- Annexin-V negative sperm, separated via MACS, exhibited significantly higher intact mitochondria post-cryopreservation-thawing (45.4% ± 8.6%) compared to controls (15.8% ± 4.6%, p<0.01).
- MACS effectively isolates non-apoptotic spermatozoa with intact membranes.
- The percentage of spermatozoa with intact transmembrane mitochondrial potential and MSR was enhanced by MACS.
Conclusions:
- Annexin-V MACS is a valuable tool for optimizing sperm cryopreservation and thawing outcomes.
- This method enhances the quality of cryopreserved sperm by preserving mitochondrial function.
- Selecting for intact sperm populations improves post-thaw viability and potential for fertilization.
