A LONGITUDINAL-STUDY OF ESTROUS CYCLICITY IN AGING C57BL-6J MICE .1. CYCLE FREQUENCY, LENGTH AND VAGINAL CYTOLOGY
A LONGITUDINAL-STUDY OF ESTROUS CYCLICITY IN AGING C57BL-6J MICE .1. CYCLE FREQUENCY, LENGTH AND VAGINAL CYTOLOGY
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DOI：
10.1095/biolreprod27.2.327
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发表时间：
1982-01-01
影响因子：
3.6
通讯作者：
FINCH, CE
中科院分区：
文献类型：
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作者：
NELSON, JF;FELICIO, LS;FINCH, CE
在 3 组单独饲养的处女小鼠中纵向测量周期频率、长度和阴道细胞学，每组间隔 3 年交错。队列中这些参数的年龄特征在质量上相似，但在数量上不同。由于周期延长和周期启动较晚，周期频率最初较低（第一阶段），直到小鼠 3-5 个月大时才达到峰值（第二阶段）。老的。第二阶段持续 7-10 个月，具体取决于队列。此后循环频率稳步下降（第三阶段）。不同队列中周期性停止的平均年龄各不相同，发生在 13 至 16 个月之间。的年龄。周期长度的年龄变化与周期频率的变化平行。在第二阶段，中位周期长度< 5 天且方差最低。在第一阶段和第三阶段，方差大约是原来的两倍，中位周期长度> 5天。尽管第二阶段的中位周期长度在几个月内保持稳定，但 4 天周期的高峰期要短得多。在所有队列中，4 天的周期直到 7-8 个月才达到峰值。 9个月时开始下降。 4 天周期的减少与周期逐渐延长有关——首先从 4 天延长到 5 天，然后是更长的周期。角化延长（> 2 天）的周期比例随着年龄的增长而增加，从周期延长初期的 < 0.35 增加到最大值 0.60。周期延长的初始阶段通常与角化延长无关的观察结果与早期证据一致，即该时期的特征是排卵前雌二醇的上升延迟而不是延长。随着年龄增长，角化延长，周期延长的比例增加，表明排卵前雌二醇的升高最终可能会延长。
Cycle frequency, length and vaginal cytology were measured longitudinally in 3 cohorts of singly housed virgin mice staggered across a 3-yr interval. The age profiles of these parameters were qualitatively similar, but quantitatively different, among cohorts. Cycle frequency was initially low (Phase I) due to prolonged cycles and late-starting cyclers, and did not peak (Phase II) until mice were 3-5 mo. old. Phase II lasted for 7-10 mo., depending on the cohort. Thereafter cycle frequency declined steadily (Phase III). The average age of cessation of cyclicity varied among cohorts, occurring between 13 and 16 mo. of age. Age changes in cycle length paralleled those of cycle frequency. During Phase II, median cycle length was < 5 days and variance was lowest. During Phases I and III, variance was about 2-fold greater and median cycle length was > 5 days. Although median cycle length remained stable for several months during Phase II, the peak period of 4-day cycles was much shorter. In all cohorts, 4-day cycles did not peak until 7-8 mo. of age and began to decline by 9 mo. The decrease in 4-day cycles was associated with a progressive lengthening of cycles-first from 4 to 5 days, then to longer cycles. The fraction of cycles with extended cornification (> 2 days) increased with advancing age from < 0.35 during the initial period of cycle lengthening to a maximum of 0.60. The observation that the initial phase of cycle prolongation is not usually associated with extended cornification is consistent with earlier evidence that this period is characterized by a delayed, rather than prolonged, preovulatory rise of estradiol. The increased fraction of prolonged cycles with extended cornification at later ages suggests that the preovulatory elevation of estradiol may ultimately be prolonged.