TY - JOUR
T1 - Dimethyl sulfoxide and glycerol as cryoprotectant agents of stallion semen
T2 - Effects on blastocyst rates following intracytoplasmic sperm injection of IVM equine oocytes
AU - Cook, Nancy L.
AU - Masterson, Keith R.
AU - Battaglia, David
AU - Beck, Rick
AU - Metcalf, Elizabeth S.
N1 - Funding Information:
Financial support for this paper was provided by the Equine IVF Fund: Oregon Health and Science University Foundation.
Publisher Copyright:
© 2020 CSIRO.
PY - 2019
Y1 - 2019
N2 - Numerous variables affect in vitro blastocyst development following intracytoplasmic sperm injection (ICSI). The paternal factor is affected by initial semen quality, processing techniques and final selection of individual spermatozoon for injection. This study investigated whether there was an effect of sperm cryoprotectant agent (CPA) on equine in vitro blastocyst production, and reviews recent developments examining how processing equine semen affects ICSI outcomes. Single ejaculates from five stallions were collected and processed in a freezing extender containing either 1 M dimethyl sulfoxide (DMSO) or 3.5% glycerol. Immature equine oocytes were obtained from ovarian follicles of mares during diestrus by transvaginal aspiration (n = 128). After in vitro maturation, MII oocytes (n = 90) were fertilised by ICSI with thawed stallion spermatozoa (n = 45 in both the DMSO and glycerol groups). The embryo cleavage rate was greater in the DMSO than glycerol group (73.3% vs 46.7% respectively; P = 0.0098), but the blastocyst development rate per fertilised oocyte was similar between the two groups (28.9% vs 15.6% respectively; P = 0.128), as was the blastocyst production rate per cleaved embryo (39.4% vs 33.3% respectively; P = 0.653). In this study, cryopreservation of equine spermatozoa in 1 M DMSO was correlated with significantly higher cleavage rates in IVM oocytes fertilised by ICSI compared with spermatozoa cryopreserved using 3.5% glycerol. Although not statistically significant in this small number of stallions, increased blastocyst production and individual stallion variability was observed among CPA treatments. This warrants further critical examination of cryoprotectants used in equine sperm subpopulations used for ICSI in a larger number of stallions.
AB - Numerous variables affect in vitro blastocyst development following intracytoplasmic sperm injection (ICSI). The paternal factor is affected by initial semen quality, processing techniques and final selection of individual spermatozoon for injection. This study investigated whether there was an effect of sperm cryoprotectant agent (CPA) on equine in vitro blastocyst production, and reviews recent developments examining how processing equine semen affects ICSI outcomes. Single ejaculates from five stallions were collected and processed in a freezing extender containing either 1 M dimethyl sulfoxide (DMSO) or 3.5% glycerol. Immature equine oocytes were obtained from ovarian follicles of mares during diestrus by transvaginal aspiration (n = 128). After in vitro maturation, MII oocytes (n = 90) were fertilised by ICSI with thawed stallion spermatozoa (n = 45 in both the DMSO and glycerol groups). The embryo cleavage rate was greater in the DMSO than glycerol group (73.3% vs 46.7% respectively; P = 0.0098), but the blastocyst development rate per fertilised oocyte was similar between the two groups (28.9% vs 15.6% respectively; P = 0.128), as was the blastocyst production rate per cleaved embryo (39.4% vs 33.3% respectively; P = 0.653). In this study, cryopreservation of equine spermatozoa in 1 M DMSO was correlated with significantly higher cleavage rates in IVM oocytes fertilised by ICSI compared with spermatozoa cryopreserved using 3.5% glycerol. Although not statistically significant in this small number of stallions, increased blastocyst production and individual stallion variability was observed among CPA treatments. This warrants further critical examination of cryoprotectants used in equine sperm subpopulations used for ICSI in a larger number of stallions.
KW - IVF
KW - assisted reproductive technology
KW - cleavage
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U2 - 10.1071/RD19266
DO - 10.1071/RD19266
M3 - Article
C2 - 32172784
AN - SCOPUS:85076374708
SN - 1031-3613
VL - 32
SP - 253
EP - 258
JO - Reproduction, Fertility and Development
JF - Reproduction, Fertility and Development
IS - 3
ER -