Matsuyama S, Chang K T, Kanuka H, Ohnishi M, Ikeda A, Nishihara M, Takahashi M
Department of Veterinary Physiololgy, University of Tokyo, Japan.
Biol Reprod. 1996 Jun;54(6):1245-51. doi: 10.1095/biolreprod54.6.1245.
We determined whether fragmentation of genomic DNA, one of the hallmarks of apoptosis, occurs during structural luteolysis in cycling rats. Corpora lutea (CL) were collected from rats at each estrous cycle stage (1800 h), and fragmented DNA was extracted. Only CL from rats at the proestrous stage showed distinct DNA fragmentation. To determine the period of occurrence of DNA fragmentation, CL were collected at several points between 1200 h on the day of proestrus and 0600 h on the day of estrus. Distinct DNA fragmentation was observed from 1800 h (proestrus) to 2400 h (proestrus), and the extent was significantly lower at 0600 h (estrus). It is known that prolactin (PRL) induces structural luteolysis in rats. To examine the role of PRL in luteal DNA fragmentation, 2-bromo-alpha-ergocryptine (BE) was used to suppress the PRL surge on the day of proestrus. CL collected at 1800 h from BE-treated rats did not show distinct DNA fragmentation, and PRL injection offset the effect of BE. Histochemical analysis with a 3'-end labeling technique confirmed the occurrence of DNA fragmentation in luteal tissue. These results suggest that apoptotic cell death occurs during PRL-induced structural luteolysis.
我们确定了基因组DNA片段化（细胞凋亡的标志之一）是否在周期性发情大鼠的结构性黄体溶解过程中发生。在每个发情周期阶段（18:00）从大鼠收集黄体（CL），并提取片段化DNA。只有发情前期大鼠的黄体显示出明显的DNA片段化。为了确定DNA片段化发生的时期，在发情前期当天12:00至发情当天06:00之间的几个时间点收集黄体。在18:00（发情前期）至24:00（发情前期）观察到明显的DNA片段化，并且在06:00（发情期）时程度显著降低。已知催乳素（PRL）可诱导大鼠发生结构性黄体溶解。为了研究PRL在黄体DNA片段化中的作用，使用2-溴-α-麦角隐亭（BE）抑制发情前期当天的PRL激增。从接受BE处理的大鼠在18:00收集的黄体未显示出明显的DNA片段化，并且注射PRL抵消了BE的作用。用3'-末端标记技术进行的组织化学分析证实了黄体组织中DNA片段化的发生。这些结果表明，凋亡性细胞死亡发生在PRL诱导的结构性黄体溶解过程中。
