Apoptosis in female genital organs-the relation between bcl-2 protein and hormone receptor

月经通常被认为是由螺旋动脉收缩引起的功能性层缺血性坏死，这取决于性激素水平。然而，最近的电子显微镜研究表明，凋亡小体主要存在于分泌晚期。众所周知，bcl2在不同的细胞系中具有阻断细胞凋亡的能力。因此，子宫内膜是研究bcl2蛋白在组织重建中的作用以及激素对bcl2表达调控的一个有吸引力的组织。本研究旨在通过比较雌激素受体(ER)和孕激素受体(PGR)在子宫组织中的分布，探讨bcl2蛋白在月经周期子宫组织中的分布，以及bcl2蛋白在月经周期中对细胞凋亡的调控作用。子宫标本取自21例在知情同意下行子宫切除术的妇女，取自宫腔内的基底液，用免疫组织化学和免疫印迹方法检测bc1-2蛋白、ER和PgR的表达，并检测子宫内膜腺、间质和肌层的平滑肌细胞中的bcl2蛋白。尤其是腺体细胞在分泌早期的增殖期表达bcl2蛋白，而在分泌晚期的月经期表达不表达。Bcl2的这种周期性表达类似于ER或PGR，bcl2在腺细胞中的表达可能受卵巢激素的调节。分泌晚期腺体细胞bcl2表达消失，与同期出现的凋亡细胞一致。因此，bcl2蛋白可能在月经过程中对细胞凋亡起着重要的调控作用。

Menses is generally regarded as ischemic necrosis of functional layr caused by contraction of spiral arteries, depending on sexual hormone levels. The recent electron-microscopic study, however, demonstrated the presence of apoptotic bodies mainly in the late secretory phase. It is well known that bcl-2 has an ability to block apoptosis in various cell lineages. Therefore, uterine endometrium is an attractive tissue for studying roles of bcl-2 protein during tissue reconstruction and also regulation of bcl-2 expression by hormones. This study was designed to clarify the distribution of bcl-2 protein in human uterine samples throughout menstrual cycle, in comparison with the distribution of estrogen receptor (ER) and progesterone receptor (PgR), and a role of bcl-2 protein in the modulation of apoptosis during menstruation. Uterine samples were collected from 21 women undergoing hysterectomy with informed consent and were obtained from the fundus within the uterine cavity and examined via immunohistochemistry and Western blot analysis for bcl-2 protein, ER and PgR.Bcl-2 protein was observed in human endometrial glandular, stromal and myometrial smooth muscle cells. Especially, glandular cells expressed bcl-2 protein at proliferative through early secretory phases but not at late secretory through menstrual phases. This cyclic expression of bcl-2 was similar to that of ER or PgR ; bcl-2 expression in glandular cells may be regulated by ovarian hormones. The disappearance of bcl-2 expression in glandular cells at late secretory phase was ocnsistent with the appearance of apoptotic cells at the same phase. Therefore, bcl-2 protein may play an important role in the modulation of apoptosis during menstruation.