Vitrification of ovarian tissue from primates and domestic ruminants: an overview.

In the last decade, vitrification protocols to preserve human ovarian tissue have been regularly reported, even more often than the protocols developed for large mammals, such as ruminants and nonhuman primates. In order to facilitate the use of domestic ruminants (cows, goats, and sheep) and nonhuman primates as animal models, application of similar protocols as used for human material is performed. Next to it, the addition of indispensable or exclusion of avoidable compounds in the vitrification of human ovarian tissue should be tested in such experiments with animal models.

Complete follicular development and recovery of ovarian function of frozen-thawed, autotransplanted caprine ovarian cortex.

Frozen-thawed ovarian cortical fragments (1 mm(3)) were autotransplanted to the uterus of completely ovariectomized goats. The grafts developed preovulatory follicles, accompanied by estrous behavior and a rise in plasma E(2) levels, demonstrating successful cryopreservation and transplantation.

Osmotic tolerance and freezability of isolated caprine early-staged follicles.

Isolated caprine early-staged follicles were submitted to osmotic tolerance tests in the presence of sucrose, ethylene glycol (EG), or NaCl solutions and were exposed to and cryopreserved (by slow or rapid cooling) in MEM alone or MEM supplemented with sucrose, EG (1.0 or 4.0 M), or both.

Effect of cryopreservation on viability, activation and growth of in situ and isolated ovine early-stage follicles.

Isolated or cortical tissue-enclosed (in situ) sheep early-stage follicles were exposed to 1.5 M dimethyl sulfoxide (DMSO), ethylene glycol (EG) or unexposed, or frozen/thawed in the presence of these cryoprotectants and then cultured for 5 days in enriched minimal essential medium (MEM) or not cultured. Cultured and uncultured follicles were classified as non-viable/viable when they were stained/not stained with trypan blue, respectively.

Presence of cumulus cells during in vitro fertilization protects the bovine oocyte against oxidative stress and improves first cleavage but does not affect further development.

The present study was conducted to evaluate the function of cumulus cells during bovine IVF Oocytes within cumulus-oocyte complexes (COCs) or denuded oocytes (DOs) were inseminated in control medium, or DOs were inseminated in cumulus cell conditioned medium (CCCM). DOs exhibited reduced cleavage and blastocyst formation rates when compared with intact COCs. The reduced blastocyst formation rate of DOs resulted from reduced first cleavage but subsequent embryo development was not changed.

Histological and ultrastructural analysis of cryopreserved sheep preantral follicles.

The aim of this study was to verify the histological and ultrastructural characteristics of sheep preantral follicles after exposure of ovarian tissue to cryopreservation in glycerol (GLY), ethylene glycol (EG), propanediol (PROH) or dimethyl sulfoxide (DMSO) in order to determine the optimum method to store sheep ovarian tissue for later experimental or clinical use. Each ovarian pair from five mixed-breed ewes was divided into 17 fragments. One (control) fragment was immediately fixed for routine histological and ultrastructural studies and the remaining (test) fragments were randomly distributed in cryotubes, equilibrated at 20 degrees C/20 min in 1.

Influences of FSH and EGF on primordial follicles during in vitro culture of caprine ovarian cortical tissue.

Factors that control the onset of folliculogenesis are critical to female gamete production, but poorly understood. The aim of the present study was to investigate the effects of FSH and EGF on the activation and growth of goat primordial follicles in vitro. To this end, pieces of goat ovarian cortex were cultured in vitro for 1, 3 or 5 days, at 39 degrees C in an atmosphere containing 5% CO(2), in minimum essential medium supplemented with insulin, transferrin, selenium, pyruvate, glutamine, hypoxanthine, BSA, penicillin, streptomycin and fungizone and with or without FSH (100 ng/ml) and/or EGF (100 ng/ml).