The effects of storing and transporting cryopreserved semen samples on dry ice

Abstract

ObjectiveThis study aimed to test the effects on sperm viability of transporting cryopreserved semen samples on dry ice.MethodsTwenty normozoospermic semen samples were cryopreserved and divided into five groups. The samples in Group 1 were immersed in liquid nitrogen throughout the experiment in cryogenic storage tanks; the cryopreserved straws in Group 2 were placed in a Styrofoam box containing dry ice and kept under these conditions for 48 hours; the samples in Group 3 were kept for 48 hours on dry ice under the same conditions as the Group 2 samples, and were then moved to a storage tank filled with liquid nitrogen; Group 4 samples were also kept for 48 hours in dry ice storage, and the Styrofoam box containing the samples was shipped by plane to assess the effects of shipping; the samples in Group 5 were shipped together with the Group 4 samples and were placed in a storage tank with liquid nitrogen after spending 48 hours stored on dry ice. After thawing, sperm parameters were analyzed for viability, vitality, and motility; spermatozoa were also tested for mitochondrial activity.ResultsSignificant decreases in motility recovery rates (P=0.01) and vitality (P=0.001) were observed in all groups when compared to the control group. Mitochondrial activity was significantly decreased only in Group 5 (P=0.04), as evidenced by greater numbers of sperm cells not stained by reagent 3,3'-diaminobenzidine.ConclusionsTransportation did not affect the quality of cryopreserved semen samples, but dry ice as a means to preserve the samples during transportation had detrimental effects upon the sperm parameters assessed in this study.

Could cryopreserved human semen samples be stored at -80°C?

“…In this study, maintenance of motility at a range of 38% to 100% and vitality at 65% to 97% after cryopreservation, among donor samples, indicated that each individual may have a different response to cryopreservation. Similar results were reported by Til et al . (2016) , who observed reduction rates of 19% to 94% in motility and from 27% to 80% in vitality.…”

“…The same was found in the present study, suggesting that -80°C is not able to keep sperm cells in the latency state obtained by the cryopreservation process, since the continuous drop in motility and vitality values resembles those observed by Paiva (2010) , when evaluating sperm survival time. Til et al (2016) found similar results when evaluating the dry ice (-79°C) transport of cryopreserved samples, proving the ineffectiveness of this temperature in maintaining semen viability.…”

“…Group 1 (Control) straws were kept in liquid nitrogen (-196°C) throughout the experiment, being analyzed after thawing without being exposed to a -80°C temperature, confirming the cryopreservation technique efficacy, and serving as analysis control for dry ice time exposure effects from other groups. Samples from Groups 2 (24 Hours), 3 (48 Hours), 4 (72 Hours) and 5 (96 Hours) were taken from liquid nitrogen and transferred to the VIP Ultra Low MDF-U76V-PE freezer, in a temperature set at -80°C, simulating dry ice storage conditions (adapted from Til et al , 2016 ).…”

“…Whenever there is a need for transporting cryopreserved human samples, it is carried out in dry ice, where the specimen is maintained at approximately -80°C, or in cryogenic bottles containing liquid nitrogen (-196°C). Dry ice is the most practical means for transporting cryopreserved semen samples, because of temperature variations that can occur in the transport of these samples ( Carrell et al ., 1996 ; Til et al ., 2016 ).…”

Dry ice is a reliable substrate for the distribution of frozen mouse spermatozoa: A multi-centric study

“…More recent papers showed that bovine semen could be maintained for short time on dry ice [34] or at −80°C [35] but not at −30°C, without losing its ability to fertilise eggs. In contrast, human spermatozoa stored and transported in dry ice quickly loose their motility and vitality [36]. Short term exposure (more than 24 h) to dry ice compromised spermatozoa motility regardless of type of cryoprotectant used [37].…”