Total motile sperm count is improved in prepare-first samples compared to freeze-first samples
Year: 2022
Type: article
Abstract: Introduction: Sperm cryopreservation is used for a range of clinical applications. While there are numerous protocols available, there is no gold standard for sperm cryopreservation. The goal of sperm cryopreservation is to recover as many motile sperm as possible, as high sperm motility and concentration are linked with successful pregnancies in assisted reproductive technology. This study investigated which order of protocol (freezing before or after preparation using density gradient centrifugation) and which density gradient (double-layered 95%/50% or single-layered 60%) resulted in higher post-thaw sperm motility and concentration. Methods: Semen samples (n=42) were divided into four equal aliquots. Two aliquots were frozen first, then prepared with either a double-layered 95%/50% or single-layered 60% Puresperm® density gradient. The final two aliquots were separately prepared with the two density gradients, followed by freezing. All samples were frozen by liquid nitrogen vapor and thawed in an incubator at 37oC for 10minutes. Post-thaw motility and concentration were assessed. Results: Total motile sperm count was higher in samples that were prepared first (49% increase; p=0.009). Although progressive motility was higher in samples that were frozen first (30% increase; p<0.001), the order of protocol had no effect on total motility (p=0.158). Preparing samples before cryopreservation elevated sperm concentration (44% increase; p=0.044). Use of the 95%/50% gradient improved total motility (53% increase; p<0.001), while the 60% gradient increased concentration (4-foldincrease; p<0.001). Conclusions: Samples prepared before freezing yielded more motile sperm than samples frozen before preparation; and the 60% gradient increased sperm concentration, compared to the 95%/50% gradient. This study contributes to the limited literature on whether sperm should be cryopreserved before or after the density gradient centrifugation method of sperm preparation, though further studies are warranted to investigate clinical pregnancy outcomes.
Institution: The University of Western Australia
Language: English
Subfield: Reproductive Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7169635205