Preservation of preantral follicles becomes very important to ensure follicle quality at the onset of cryopreservation or in vitro culture. However, for domestic animals, the ovarian donor of preantral follicles for in vitro studies is commonly encountered far away from reproduction laboratories. We investigated the effectiveness of coconut water and BraunCollins solutions on the preservation of goat preantral follicles. At the slaughterhouse, the ovarian pair of each animal was divided into 19 fragments. One ovarian fragment was immediately fixed (Control -Time 0). The other 18 fragments were randomly distributed into tubes containing 2 mL of coconut water or Braun-Collins solution at 4 °, 20 ° or 39 °C and then stored for 4, 12 or 24 h. Histological analysis showed that the storage of ovarian fragments in coconut water and Braun-Collins solutions at 20 ° or 39 °C for 12 or 24 h significantly reduced (P < 0.05) the percentage of morphologically normal preantral follicles when compared with the control. However, storage in coconut water at 20 °C for 4 h and in both solutions at 4 °C kept the percentage at control values. Ultrastructural analysis of follicles exposed to the stated conditions confirmed the integrity of preantral follicles stored at 4 °C in Braun-Collins and coconut water solutions for up to 12 and 24 h, respectively. Reduced cellular metabolism at 4 °C may explain why the best preservation of preantral follicles was at 4 °C, which may suggest a useful method for ovary transport in the future.

No abstract

No abstract

No abstract

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 1.8 mL of minimal essential medium (MEM) containing 1.5 or 3 M GLY, EG, PROH or DMSO and then either fixed for morphological studies to determine their possible toxic effect or frozen/thawed and then fixed to test the effect of cryopreservation on preantral follicles. Histological analysis showed that, compared to control fragments, all cryoprotectants at both concentrations significantly reduced the percentage of normal preantral follicles in ovarian fragments prior to or after cryopreservation. PROH 3.0 M appeared to exert a more toxic effect (P<0.05) than the other cryoprotectants in noncryopreserved tissues. After freezing/thawing, the highest (P<0.05) percentages of lightmicroscopical normal preantral follicles were observed in ovarian fragments cryopreserved in EG (1.5 and 3 M) or DMSO (1.5 M). However, transmission electronic microscopical (TEM) examination showed that only the DMSO-cryopreserved preantral follicles had normal ultrastructure. The data suggest that sheep preantral follicles should be cryopreserved with 1.5 M DMSO for later clinical or experimental application.

The objective was to determine the morphological and ultrastructural features of sheep primordial follicles preserved in either 0.9% saline solution or TCM 199 at different temperatures. Soon after death, the ovarian pair of each ewe (n=5) was divided into 25 fragments. One fragment was immediately fixed for morphological evaluation (control). The other 24 fragments were randomly distributed in tubes containing 2 ml of 0.9% saline solution or TCM 199 and maintained at 4, 20 or 39 °C for 2, 4, 12, or 24 h. Based on histological assessment, storage of ovarian fragments in 0.9% saline solution at 20 °C for up to 24 h and in both solutions at 39 °C for 4, 12 or 24 h increased (P<0.01) the percentage of degenerate primordial follicles compared with controls. In contrast, preservation at 4 °C in both solutions, kept the percentage of morphologically normal primordial follicles similar to control values. Although histological integrity of primordial follicles was maintained in fragments stored at 20 °C for up to 24 h in TCM 199, these results were not confirmed by ultrastructural analysis. Based on transmission electron microscopy, only primordial follicles stored at 4 °C for up to 24 h, at 20 °C for up to 12 h and at 39 °C for up to 2 h in both solutions were ultrastructurally normal. In conclusion, sheep primordial follicles were successfully preserved at 4 °C for up to 24 h, at 20 °C for up to 12 h and at 39 °C for 2 h in 0.9% saline solution or TCM 199.

Cryopreservation of ovarian tissue may be a potential alternative for the conservation of genetically superior animals, including high milk-and meat-producing goat breeds. However, until now, no information was available concerning the cryopreservation of preantral follicles (PF) enclosed in caprine ovarian tissue. The objective of the present study was to evaluate the structural and ultrastructural characteristics of caprine PF after exposure to and cryopreservation of ovarian tissue in 1.5 and 3 M glycerol (GLY) and ethylene glycol (EG). At the slaughterhouse, each ovarian pair from five adult mixed breed goats was divided into nine fragments and randomly distributed into treatment groups. One fragment was immediately fixed for histological examination and ultrastructural analysis, after slaughter (control). Four of the ovarian fragments were equilibrated at 20 °C for 20 min in 1.8 ml of MEM containing 1.5 or 3 M GLY or EG for a toxicity test and the final four fragments were slowly frozen using these cryoprotectants at the concentrations above. After toxicity testing and freezing/thawing, the ovarian fragments were fixed for histological examination. Histological analysis showed that after toxicity testing and cryopreservation of the ovarian tissue in GLY or EG at both concentrations, the percentage of normal PF was significantly lower than controls. Ultrastructural analysis of PF frozen in 1.5 and 3 M GLY, as well as 3 M EG demonstrated that these follicles remained morphologically normal. In conclusion, we demonstrated cryopreservation of caprine PF in ovarian tissue.

No abstract