TY - JOUR
T1 - Equine sperm membrane phase behavior
T2 - The effects of lipid-based cryoprotectants
AU - Ricker, J. V.
AU - Linfor, J. J.
AU - Delfino, W. J.
AU - Kysar, P.
AU - Scholtz, E. L.
AU - Tablin, F.
AU - Crowe, J. H.
AU - Ball, B. A.
AU - Meyers, S. A.
PY - 2006/2
Y1 - 2006/2
N2 - The plasma membrane of sperm can undergo lipid phase separation during freezing, resulting in irreversible damage to the cell. The objective of our study was to examine the membrane phase behavior of equine spermatozoa in the absence and presence of lipid-based cryoprotectants. Biophysical properties of sperm membranes were investigated with Fourier-transform infrared spectroscopy. Compared to fresh untreated sperm, postthaw untreated sperm showed extensive lipid phase separation and rearrangement. In contrast, postthaw sperm that were cryopreserved in egg phosphatidylcholine (egg PC)- or soy phosphatidylcholine (soy PC)-based diluents showed similar lipid phase behavior to that of fresh, untreated sperm. Studies with a deuterium-labeled PC lipid (POPCd-31) suggest that exogenous lipid from the diluents are strongly associated with the sperm membrane, and scanning electron microscopy images of treated sperm show the presence of lipid aggregates on the membrane surface. Thus, the exogenous lipid does not appear to be integrated into the sperm membrane after cryopreservation. When compared to a standard egg-yolk-based diluent (INRA 82), the soy and egg PC media preserved viability and motility equally well in postthaw sperm. A preliminary fertility study determined that sperm cryopreserved in the soy PC-based medium were capable of fertilization at the same rate as sperm frozen in the conventional INRA 82 medium. Our results show that pure lipid-based diluents can prevent membrane damage during cryopreservation and perform as well as a standard egg-yolk-based diluent in preserving sperm viability, motility, and fertility.
AB - The plasma membrane of sperm can undergo lipid phase separation during freezing, resulting in irreversible damage to the cell. The objective of our study was to examine the membrane phase behavior of equine spermatozoa in the absence and presence of lipid-based cryoprotectants. Biophysical properties of sperm membranes were investigated with Fourier-transform infrared spectroscopy. Compared to fresh untreated sperm, postthaw untreated sperm showed extensive lipid phase separation and rearrangement. In contrast, postthaw sperm that were cryopreserved in egg phosphatidylcholine (egg PC)- or soy phosphatidylcholine (soy PC)-based diluents showed similar lipid phase behavior to that of fresh, untreated sperm. Studies with a deuterium-labeled PC lipid (POPCd-31) suggest that exogenous lipid from the diluents are strongly associated with the sperm membrane, and scanning electron microscopy images of treated sperm show the presence of lipid aggregates on the membrane surface. Thus, the exogenous lipid does not appear to be integrated into the sperm membrane after cryopreservation. When compared to a standard egg-yolk-based diluent (INRA 82), the soy and egg PC media preserved viability and motility equally well in postthaw sperm. A preliminary fertility study determined that sperm cryopreserved in the soy PC-based medium were capable of fertilization at the same rate as sperm frozen in the conventional INRA 82 medium. Our results show that pure lipid-based diluents can prevent membrane damage during cryopreservation and perform as well as a standard egg-yolk-based diluent in preserving sperm viability, motility, and fertility.
KW - Gamete biology
KW - Sperm
KW - Sperm motility and transport
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U2 - 10.1095/biolreprod.105.046185
DO - 10.1095/biolreprod.105.046185
M3 - Article
C2 - 16251500
AN - SCOPUS:31044448977
SN - 0006-3363
VL - 74
SP - 359
EP - 365
JO - Biology of Reproduction
JF - Biology of Reproduction
IS - 2
ER -