Conservação de folículos pré-antrais bovinos em solução salina 0,9% ou TCM 199

The base medium affects ultrastructure and survival of bovine preantral follicles cultured in vitro

The aim of this study was to determine the effectiveness of minimum essential medium alpha modification (α-MEM), tissue culture medium 199 (TCM-199), and McCoy's medium (McCoy's) on IVC of preantral follicles included in the bovine ovarian cortex (in situ). Bovine ovarian fragments were cultured in α-MEM, TCM-199, or McCoy supplemented ((+)) with glutamine, insulin, transferrin, selenium, ascorbic acid, BSA, penicillin, streptomycin, and HEPES buffer in 24-well plates, at 37 °C and 5% CO2 for 1 or 7 days. The morphology of follicles, normal, primordial and development (primary and secondary), as well as viability and morphometric variables of follicles and oocytes were assessed. The morphology and morphometry of preantral follicles were analyzed by ANOVA followed by the Tukey and Dunnett tests, and viability variables were determined by the chi-square test. The results showed that TCM-199(+) reduced significantly (P < 0.05) the percentage of morphologically normal and viable follicles after 7 days of culture compared to the control. Similar results were observed in McCoy(+), in which the percentage of viable follicles after 7 days of culture was significantly lower (P < 0.05) than in the control. However, it was similar (P > 0.05) between α-MEM(+) and TCM-199(+). Moreover, follicular diameters in McCoy(+) and TCM-199(+) were significantly smaller (P < 0.05) than in control and α-MEM(+) after 7 days of culture. In addition, the ultrastructure of preantral follicles was similar between the control and α-MEM(+) after 7 days of culture. In conclusion, α-MEM(+) showed to be the most effective medium to preserve morphology, morphometry and ultrastructure of bovine preantral follicles, ensuring their viability and growth after in situ culture.

Lower apoptosis rate in ovine preantral follicles from ovaries stored in supplemented preservation media

The aim of this study was to investigate the effect of ovarian tissue transportation conditions (medium and period of time) on the morphology, apoptosis and development of ovine preantral follicles cultured in vitro. Each ovarian pair was cut into nine slices, with one fragment being fixed immediately (fresh control). The remaining fragments were placed individually in cryotubes containing conservation medium (minimal essential medium (MEM) without supplementation or MEM+ - with supplementation) and stored at 35ºC for 6 or 12 h without (non-cultured) or with subsequent culture for 5 days. Then, the fragments were processed for histological and terminal deoxynucleotidyl transferase (TdT) mediated dUTP nick-end labelling (TUNEL) examination. Preservation of ovarian slices in MEM or MEM+ (non-cultured) resulted in similar percentages of normal follicles when compared with the fresh control. Nevertheless, compared with the fresh control, a decrease in the percentage of normal follicles was observed in tissues cultured for 5 days. Only for tissues preserved in supplemented medium (MEM+) for 6 h, the percentage of TUNEL positive cells was similar between non-cultured tissues and tissues cultured for 5 days. Follicular activation and growth (follicular and oocyte diameter) were higher in cultured tissues than in fresh control or non-cultured tissues, except those from fragments preserved for 6 h in MEM and then cultured for 5 days in which no growth was observed. In conclusion, ovine ovarian tissue was successfully preserved in supplemented medium (MEM+) at a temperature close to physiological values (35°C) for up to 6 h without affecting apoptosis in the ovarian follicles and their ability to develop in vitro.

Short-term preservation of Pecari tajacu ovarian preantral follicles using phosphate buffered saline (PBS) or powdered coconut water (ACP(r)) media

We compare protocols for the short-term preservation of collared peccarie's ovarian preantral follicles (PFs) by using phosphate buffered saline- (PBS) or powdered coconut water- (ACP(r)) based medium. For morphology analysis each pair of ovaries collected from six females was divided into nine fragments. One fragment was destined for morphology analysis (histology and transmission electron microscopy - TEM), constituting the control group and the other fragments were placed in tubes with PBS or ACP(r), packed in 5 L Styrofoam boxes, stored for 4h, 12h, 24h, and 36h, and then analyzed. For viability analysis a pair of ovaries from two additional females was divided into nine fragments; one fragment was immediately destined for viability analysis (Trypan blue test) and the other fragments were stored as previously described, until 24h and then analyzed. After 4h storage in ACP(r) medium, the follicular integrity was similar to control (87.8% vs 94.4%, respectively); however, ultrastructural analyses revealed swollen mitochondria as the first signals of PF degeneration. It was observed that ACP(r) (66.7%) was more efficient than PBS (49.4%) to preserve the morphological integrity after 36h storage (P<0.05); however, no differences were observed on follicular viability (P>0.05). In conclusion, the use of the ACP(r) is recommended for the short-term preservation of Pecari tajacupreantral follicles.

Effects of α-tocopherol and ternatin antioxidants on morphology and activation of goat preantral follicles in vitro cultured

The effects of α-tocopherol and ternatin on the morphology, activation, and growth of goat preantral follicles in vitro cultured, for one or five days, were evaluated. Ovarian fragments were immediately fixed (non-cultured control) or in vitro cultured for one or five days in Minimum Essential Medium (MEM) with or without α-tocopherol or ternatin supplementation, both at concentrations of 5, 10, or 15µM, corresponding to the following treatments: MEM, TOC5, TOC10, TOC 15, TER5, TER10, and TER15. The percentages of morphologically normal preantral follicles in non-cultured ovarian tissue (control) was 73.2% and after five days of culture, there was a decrease on these percentages in all treatments (P<0.05) when compared with non-cultured control. Culture of ovarian cortex for five days increased the percentages of follicular activation in all treatments (P<0.05). Ultrastructural analysis did not confirm the integrity of caprine preantral follicles cultured for five days in medium containing antioxidants. This study demonstrated that α-tocopherol and ternatin can promote follicular activation; however, addition of these antioxidants in the tested concentrations reduced the follicular viability after in vitro culture.

Preservation of bovine preantral follicle viability and ultra-structure after cooling and freezing of ovarian tissue

Bovine preantral follicles within ovarian fragments were exposed and cryopreserved in absence or presence of 1.5M glycerol (GLY), ethylene glycol (EG), propanediol (PROH) or dimethyl sulfoxide (DMSO), undergoing a previous cooling at 20 degrees C for 1h (protocol 1) or at 4 degrees C for 24h (protocol 2) in 0.9% saline solution. At the end of each treatment, preantral follicles were classified as non-viable/viable when they were stained/not stained with trypan blue, respectively. To confirm viability staining, ultra-structure of the follicles was evaluated by transmission electronic microscopy (TEM). Data were compared by Chi-square test (P<0.05). The storage of the ovaries at 20 degrees C for 1h (78%) and 4 degrees C for 24h (80%) did not reduce significantly the percentage of viable preantral follicles when compared to the control (75%). Similar results were obtained when ovarian fragments, respectively, for protocols 1 and 2, were exposed to MEM (78 and 77%), 1.5M EG (78 and 71%), as well as frozen in 1.5M EG (74 and 77%). Percentages of viable follicles in control were similar to those observed after exposure (75%) and freezing (76%) in presence of 1.5M DMSO only when protocol 1 was used. The increase of the concentration from 1.5 to 3.0M, for all cryoprotectants, reduced significantly the percentage of viable preantral follicles after freezing. Ultra-structural analysis has confirmed trypan blue results, showing that not only basement membrane, but also organelles, were intact in viable preantral follicles. In conclusion, ovarian tissue cooling at 4 degrees C for 24h before cryopreservation (protocol 2) does not affect the viability of bovine preantral follicles when 1.5M EG is present in the cryopreservation medium.