SummaryThis study aimed to evaluate the effects of dexamethasone on development, viability, antrum formation and ultrastructural integrity of bovine secondary follicles cultured in vitro for 18 days. Bovine ovaries were obtained from slaughterhouses and secondary follicles of ~150–200 µm diameter were isolated and cultured in the laboratory in TCM-199+ alone or supplemented with different concentrations of dexamethasone (1, 10, 100 and 1000 ng/ml). Follicle viability was evaluated after the culture period, using calcein-AM (viable) and ethidium homodimer (nonviable). Follicle diameters and antrum formation were evaluated at days 0, 6, 12 and 18. Before or after in vitro culture, follicles were fixed for histological and ultrastructural analysis. Follicle diameters were evaluated using analysis of variance and Kruskal–Wallis test, while chi-squared test was used to evaluate the percentage of viable follicles and antrum formation (P < 0.05). Follicles cultured for 6 days with all treatments increased their diameters significantly, but there was no significant difference between treatments at the end of the culture period. In vitro cultured follicles showed antral cavity formation at the end of the culture period, but no influence of dexamethasone was seen. Ultrastructural analysis showed that follicles cultured with dexamethasone (1, 10, 100 and 1000 ng/ml) had well preserved granulosa cells. However, oocytes from follicles cultured with 10, 100 or 1000 ng/ml dexamethasone showed signs of degeneration. It can be concluded that follicles cultured in vitro in the presence of dexamethasone demonstrated continuous in vitro growth, but oocytes from follicles cultured with 10, 100 or 1000 ng/ml dexamethasone had poor ultrastructure.

中文翻译：

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地塞米松对体外培养的牛次级卵泡生长、活力及超微结构的影响

总结本研究旨在评估地塞米松对培养的牛次级卵泡发育、活力、胃窦形成和超微结构完整性的影响体外18天。从屠宰场获得牛卵巢，并在 TCM-199 实验室中分离和培养直径约 150–200 µm 的次级卵泡+单独使用或补充不同浓度的地塞米松（1、10、100 和 1000 ng/ml）。在培养期后，使用 calcein-AM（有活力）和乙锭同型二聚体（无活力）评估卵泡活力。在第 0、6、12 和 18 天评估卵泡直径和胃窦形成。之前或之后体外培养，固定滤泡进行组织学和超微结构分析。使用方差分析和 Kruskal-Wallis 检验评估卵泡直径，而使用卡方检验评估存活卵泡和胃窦形成的百分比。磷< 0.05)。所有处理培养6天的卵泡直径显着增加，但在培养期结束时处理之间没有显着差异。体外培养的卵泡在培养期结束时显示窦腔形成，但没有看到地塞米松的影响。超微结构分析表明，用地塞米松（1、10、100 和 1000 ng/ml）培养的卵泡具有保存完好的颗粒细胞。然而，用 10、100 或 1000 ng/ml 地塞米松培养的卵泡中的卵母细胞显示出退化迹象。可以得出结论，培养的卵泡体外在地塞米松存在下表现出连续体外生长，但用 10、100 或 1000 ng/ml 地塞米松培养的卵泡的卵母细胞超微结构较差。