Makker Annu, Singh M M
Endocrinology Division, Central Drug Research Institute, Lucknow-226 001, India.
Med Res Rev. 2006 Nov;26(6):699-746. doi: 10.1002/med.20061.
Fertility in humans and other mammalian species depends absolutely on synchronous events that render the developing blastocyst and the receiving uterus competent for implantation. Endometrial receptivity is defined as the period during which the endometrial epithelium acquires functional, but transient, ovarian steroid-dependent status supportive to blastocyst acceptance and implantation. Once inside the uterus, the blastocyst is surrounded by an intact luminal epithelium, which is considered to act as barrier to its attachment, except for this short period of high endometrial receptivity to blastocyst signal(s). Its transport and permeability properties, in conjunction with cellular action of the endometrium and the embryo, have been suggested to influence creation and maintenance of informational and nutritional status of uterine luminal milieu. This period, also termed as the 'window of implantation,' is limited to days 20-24 of menstrual cycle in humans. However, establishment of endometrial receptivity is still a biological mystery that remains unsolved despite marked advances in our understanding of endometrial physiology following extensive research associated with its development and function. This review deals with various structural, biochemical, and molecular events in the endometrium coordinated within the implantation window that constitute essential elements in the repertoire that signifies endometrial receptivity and is aimed to achieve a better understanding of its relationship to fertility, infertility, and for the development of targeted antifertility agents for human use and welfare.
人类和其他哺乳动物的生育能力绝对依赖于同步发生的事件，这些事件使发育中的囊胚和接受胚胎的子宫具备着床能力。子宫内膜容受性被定义为子宫内膜上皮获得功能性但短暂的、依赖卵巢甾体激素的状态的时期，这种状态有助于囊胚的接受和着床。一旦进入子宫，囊胚就被完整的腔上皮所包围，除了子宫内膜对囊胚信号具有高容受性的这段短暂时期外，该腔上皮被认为是囊胚附着的屏障。有人提出，其运输和通透性特性，连同子宫内膜和胚胎的细胞作用，会影响子宫腔内环境信息和营养状态的形成与维持。这个时期，也被称为“着床窗”，在人类月经周期中仅限于第20 - 24天。然而，尽管在对子宫内膜生理学的认识方面，随着对其发育和功能的广泛研究取得了显著进展，但子宫内膜容受性的建立仍然是一个未解的生物学谜团。本综述探讨了着床窗内子宫内膜中各种结构、生化和分子事件，这些事件是构成表明子宫内膜容受性的要素，旨在更好地理解其与生育、不孕的关系，以及开发用于人类的靶向抗生育药物以促进人类健康。
