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Influence of cryopreservation on the microelectrophoretic motility (EPM) of human spermatozoa
1Department of Dermatology/Andrology, University of Leipzig, Germany.
Abstract:
The net surface charge of spermatozoa represents a characteristic of the plasmamembrane. It can be evaluated indirectly, by the measurement of the sperm electrophoretic motility (EPM). The EPM of washed human spermatozoa was determined in the microelectrophoresis to investigate three problems: (a) intra- and interindividual variation coefficients of EPM of cryopreserved spermatozoa, (b) effects of cryopreservation medium, temperature shock and cryoprotection on the EPM, (c) relationship between the EPM and the cryotolerance of the spermatozoa. The inter- and intrain-dividual variation coefficients of the sperm EPM of 24 cryopreserved semen samples of 6 fertile semen donors amounted to 7% and to 6%, respectively. The cryopreservation did not cause a significant change of sperm EPM in contrast to the temperature shock in liquid nitrogen. Temporary incubation of spermatozoa with egg yolk decreased their EPM. A significant correlation between EPM and the cryotolerance ascertained by the alteration of sperm motile efficiency could be found. After contact with egg yolk spermatozoa achieved a behaviour that corresponded to a better cryotolerance.
Insights
Sperm surface charge, measured by sperm electrophoretic motility (EPM), shows low variation in cryopreserved samples. Egg yolk improves sperm cryotolerance, correlating with EPM changes.
Area of Science:
- Reproductive Biology
- Sperm Physiology
- Cryobiology
Background:
- The net surface charge of spermatozoa is a key plasmamembrane characteristic.
- Sperm electrophoretic motility (EPM) offers an indirect method to assess this surface charge.
- Understanding EPM is crucial for optimizing sperm cryopreservation techniques.
Purpose of the Study:
- To investigate the variation in EPM for cryopreserved human spermatozoa.
- To evaluate the impact of cryopreservation, temperature shock, and cryoprotective agents on EPM.
- To determine the relationship between EPM and sperm cryotolerance.
Main Methods:
- Microelectrophoresis was used to measure the EPM of washed human spermatozoa.
- Analysis included intra- and interindividual variation coefficients.
- Effects of cryopreservation medium, temperature shock, and egg yolk incubation were assessed.
Main Results:
- Low intra- (6%) and interindividual (7%) variation coefficients were observed for sperm EPM.
- Cryopreservation itself did not significantly alter EPM, but temperature shock did.
- Incubation with egg yolk decreased EPM but was associated with improved cryotolerance.
Conclusions:
- Sperm EPM is a reliable parameter with low variability in cryopreserved samples.
- Egg yolk's effect on EPM suggests a protective mechanism contributing to enhanced cryotolerance.
- EPM measurement can potentially predict sperm cryotolerance, aiding in optimizing assisted reproductive technologies.