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Published on: March 4, 2018
DNA integrity is maintained after freeze-drying of human spermatozoa
Luca Gianaroli1, Maria Cristina Magli, Ilaria Stanghellini
1Società Italiana Studi Medicina della Riproduzione (S.I.S.Me.R.), Reproductive Medicine Unit, Bologna, Italy. luca.gianaroli@sismer.it
Objective:
To evaluate the effects on human spermatozoa of freeze-drying, also known as lyophilization, and of cryopreservation in liquid nitrogen.
Design:
Prospective experimental study.
Setting:
Reproductive medicine unit and a private IVF center.
Patient(S):
Thirty healthy male donors.
Intervention(S):
Sperm samples from 30 donors divided as two aliquots, one to be lyophilized and the other to be cryopreserved in liquid nitrogen.
Main Outcome Measure(S):
Assessment of count, motility, morphology, viability, DNA integrity, chromosomal status, and birefringence properties of lyophilized and cryopreserved human spermatozoa compared with the same parameters in the fresh sample.
Result(S):
Although sperm viability and motility were totally compromised after freeze-drying, the sperm chromatin structure was not altered in comparison with fresh samples, which demonstrated that the procedure did not affect DNA integrity. The sperm-head inner protoplasmic structures were also preserved, which was estimated by assessing the corresponding birefringence characteristics. After cryopreservation with liquid nitrogen, the motility, viability, and DNA integrity of spermatozoa were statistically significantly reduced compared with the fresh samples; the proportion of sperm cells with abnormal head birefringence increased meaningfully.
Conclusion(S):
The process of freeze-drying deeply damages cell membranes; however, unlike with liquid nitrogen preservation, it does not affect DNA integrity.
Insights
Freeze-drying severely impacts sperm viability and motility but preserves DNA integrity. Cryopreservation reduces sperm motility, viability, and DNA integrity, unlike freeze-drying.
Area of Science:
- Reproductive biology
- Sperm cryobiology
- Biopreservation techniques
Background:
- Sperm preservation is crucial for assisted reproductive technologies.
- Evaluating novel preservation methods like freeze-drying (lyophilization) is essential.
- Comparing freeze-drying with conventional liquid nitrogen cryopreservation is needed.
Purpose of the Study:
- To assess the impact of freeze-drying and liquid nitrogen cryopreservation on human spermatozoa.
- To compare the effects of these preservation methods on sperm parameters including DNA integrity and morphology.
Main Methods:
- A prospective experimental study involving 30 healthy male donors.
- Sperm samples were divided into two aliquots: one for freeze-drying and one for cryopreservation.
- Key parameters assessed included sperm count, motility, morphology, viability, DNA integrity, and birefringence.
Main Results:
- Freeze-drying compromised sperm viability and motility but preserved DNA integrity and birefringence.
- Liquid nitrogen cryopreservation significantly reduced sperm motility, viability, and DNA integrity.
- Abnormal sperm head birefringence increased significantly after cryopreservation.
Conclusions:
- Freeze-drying causes significant cell membrane damage but protects sperm DNA integrity.
- Liquid nitrogen cryopreservation negatively affects sperm viability, motility, and DNA integrity.
- Freeze-drying offers an alternative preservation method with distinct advantages for DNA preservation.
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