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Published on: March 4, 2018
Quantitative prospective experimental study on time-dependent ultrastructural changes in human spermatozoa after
Sofia Coelho1, Elsa Oliveira2, Margarida Fonseca Cardoso3
1RISE-Health, Genetics Unit, Department of Pathology, Faculty of Medicine, University of Porto, Portugal.
Tissue & Cell
|June 10, 2026
Summary
Sperm cryopreservation damages sperm head membranes and acrosomal vesicles, potentially reducing fertilization success in assisted reproduction (ART) procedures. Further inspection of sperm quality post-cryopreservation is crucial.
Area of Science:
- Reproductive Biology
- Cell Biology
- Cryobiology
Background:
- Sperm cryopreservation is standard in assisted reproduction (ART).
- While generally safe, it may decrease fertilization potential.
- Ultrastructural analysis can reveal cryopreservation-induced cellular changes.
Purpose of the Study:
- To investigate the ultrastructural alterations in human spermatozoa after cryopreservation.
- To assess the impact of cryopreservation duration (1 and 7 months) on sperm ultrastructure.
Main Methods:
- Human semen samples were cryopreserved using a rapid freezing protocol with glycerol and raffinose.
- Paired, repeated measures were used to analyze sperm ultrastructure before and after cryopreservation (1 and 7 months).
- Transmission electron microscopy was employed for detailed ultrastructural analysis.
Main Results:
- Cryopreservation significantly increased anomalous sperm with head membrane and acrosomal vesicle changes (fresh: 26.8% vs. 1-Mo: 52.2%, 7-Mo: 57.4%).
- Total detachment of the sperm head membrane increased significantly post-cryopreservation (fresh: 9.3% vs. 1-Mo: 26.3%, 7-Mo: 34.5%).
- Acrosomal vesicle detachment (apical and total) also showed significant increases after cryopreservation periods.
Conclusions:
- Sperm cryopreservation negatively impacts both the sperm head membrane and the acrosomal vesicle.
- These ultrastructural changes likely decrease the functional competence of spermatozoa.
- Detailed sperm inspection is vital for selection in ART following cryopreservation.
