Superovulation protocols have been described for different mouse strains, however the numbers of animals used are still high and still little information is known about hormone administration schedules and estrous cycle phases. In this study, we aimed to optimize a superovulation protocol by injecting 5 IU of pregnant mare serum gonadotropin followed by 5 IU of hCG 48 h later, using three different schedules related to the beginning of the dark cycle (3, 5 and 7 pm) in a light cycle of 7 am to 7 pm, with light on at 7 am. C57BL/6J mice at 3, 4 and 5 weeks of age were used and the estrous cycle phase for times of PMSG and hCG injections was also analyzed. Total oocyte number was counted in the morning after hCG injection. Hormones given at 3 weeks of age at 3 pm (59 ± 15 oocytes) and 7 pm (61 ± 10 oocytes) produced a significantly higher oocyte number compared with oocytes numbers collected from females at the same age at 5 pm (P = 0.0004 and <0.0001 respectively). Females at 4 and 5 weeks of age produced higher numbers of oocytes when superovulated at 7 pm. No statistical differences between females at different phases of the estrous cycle were found. These results showed that in C57BL/6J mice, hormones should be given at 3 or 7 pm for females at 3 weeks of age, however older females should be superovulated closer to the beginning of the dark cycle to reduce female mouse use and increase the numbers of oocytes produced per female.

中文翻译：

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C57BL/6J 小鼠超排卵：优化时间表和年龄以增加卵母细胞产量并减少动物使用

已经针对不同的小鼠品系描述了超排卵方案，但是使用的动物数量仍然很高，关于激素给药时间表和发情周期阶段的信息仍然很少。在这项研究中，我们的目标是通过注射 5 IU 怀孕母马血清促性腺激素，然后在 48 小时后注射 5 IU hCG 来优化超排卵方案，使用与黑暗周期开始相关的三种不同时间表（下午 3 点、5 点和 7 点）在早上 7 点到晚上 7 点的光照周期中，早上 7 点点亮。使用 3、4 和 5 周龄的 C57BL/6J 小鼠，还分析了 PMSG 和 hCG 注射时间的动情周期阶段。在 hCG 注射后的早晨计数总卵母细胞数。磷= 0.0004 和 <0.0001）。4 周龄和 5 周龄的雌性在晚上 7 点排卵时产生更多数量的卵母细胞。发情周期不同阶段的女性之间没有发现统计学差异。这些结果表明，在 C57BL/6J 小鼠中，雌性 3 周龄的雌性应在下午 3 点或 7 点给予激素，但年龄较大的雌性应在接近黑暗周期开始时进行超排卵，以减少雌性小鼠的使用并增加数量每个女性产生的卵母细胞数。