TY - JOUR
T1 - Ultrastructure of human mature oocytes after slow cooling cryopreservation with ethylene glycol
AU - Nottola, Stefania Annarita
AU - Coticchio, G.
AU - de Santis, L.
AU - Macchiarelli, G.
AU - Malone, M.
AU - Bianchi, S.
AU - Iaccarino, M.
AU - Flamigni, C.
AU - Borini, A.
PY - 2008/9
Y1 - 2008/9
N2 - The morphological characteristics of frozen-thawed human mature oocytes (n = 12) were studied by light and transmission electron microscopy following cryopreservation using a slow cooling protocol including increasing concentrations of ethylene glycol (0.5-1.5 mol/1) and sucrose 0.2 mol/l in the freezing solution. Fresh human mature oocytes (n = 12) were used as controls. Fresh and frozen-thawed oocytes appeared rounded in section, with a homogeneous cytoplasm, an intact oolemma and a continuous zona pellucida. Disorganization of mitochondria-smooth endoplasmic reticulum aggregates and a decreased complement of microvilli and cortical granules were frequently observable in frozen-thawed oocytes. Increased density of the inner zona pellucida, possibly related to the occurrence of zona 'hardening', was sometimes found associated with a reduced amount of cortical granules. In addition, delamination of the zona pellucida was evident in some frozen-thawed samples. Finally, numerous vacuoles and secondary lysosomes were detected in the ooplasm of most frozen-thawed oocytes. In conclusion, frozen-thawed oocytes treated with ethylene glycol may show a variety of ultrastructural alterations, possibly related, at least in part, to the use of this cryoprotectant. Thus, the ethylene glycol-based protocol of slow cooling herein described does not seem to offer significant advantages in terms of oocyte structural preservation.
AB - The morphological characteristics of frozen-thawed human mature oocytes (n = 12) were studied by light and transmission electron microscopy following cryopreservation using a slow cooling protocol including increasing concentrations of ethylene glycol (0.5-1.5 mol/1) and sucrose 0.2 mol/l in the freezing solution. Fresh human mature oocytes (n = 12) were used as controls. Fresh and frozen-thawed oocytes appeared rounded in section, with a homogeneous cytoplasm, an intact oolemma and a continuous zona pellucida. Disorganization of mitochondria-smooth endoplasmic reticulum aggregates and a decreased complement of microvilli and cortical granules were frequently observable in frozen-thawed oocytes. Increased density of the inner zona pellucida, possibly related to the occurrence of zona 'hardening', was sometimes found associated with a reduced amount of cortical granules. In addition, delamination of the zona pellucida was evident in some frozen-thawed samples. Finally, numerous vacuoles and secondary lysosomes were detected in the ooplasm of most frozen-thawed oocytes. In conclusion, frozen-thawed oocytes treated with ethylene glycol may show a variety of ultrastructural alterations, possibly related, at least in part, to the use of this cryoprotectant. Thus, the ethylene glycol-based protocol of slow cooling herein described does not seem to offer significant advantages in terms of oocyte structural preservation.
KW - Cryopreservation
KW - Ethylene glycol
KW - Human
KW - Oocyte
KW - Slow cooling
KW - Ultrastructure
UR - http://www.scopus.com/inward/record.url?scp=52049115883&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=52049115883&partnerID=8YFLogxK
M3 - Article
C2 - 18765007
AN - SCOPUS:52049115883
VL - 17
SP - 368
EP - 377
JO - Reproductive BioMedicine Online
JF - Reproductive BioMedicine Online
SN - 1472-6483
IS - 3
ER -