Bhattacharya Koushik, Sengupta Pallav, Dutta Sulagna, Syamal Alak Kumar
Department of Physiology, Maitri College of Dentistry and Research Center, Anjora, Durg, Chhattisgarh, India.
Physiology Unit, Faculty of Medicine, Bioscience and Nursing, MAHSA University, Jenjarom, Malaysia.
Mol Cell Biochem. 2023 Feb;478(2):285-289. doi: 10.1007/s11010-022-04505-1. Epub 2022 Jul 5.
Estrogens and progesterone, in unison and/or separately, synchronize the distinct events of blastocyst development, uterine priming and receptivity induction for implantation. In contrast to high implantation failure rates, the mechanistic concepts regarding the uterine receptivity for implantation still remain elusive. The present study aims to define the minimum estradiol (E) dose to induce uterine receptivity for successful implantation in post-coitus bilaterally ovariectomized (BLO) progesterone-primed uterus of mice. Post-coital sperm-positive adult female mice were divided into two groups. In both the groups, delayed implantation was induced by BLO on post-coitus Day 4 (D4). Group 1 received 2 mg of progesterone (P) from D5 until sacrifice, and E injection of 3.0, 10.0, 25.0 and 50.0 ng on D7. On D8, all mice of this group were sacrificed except the mice that received second dose of 25.0 ng of E on D8 and were sacrificed on D9. Group 2 followed the same doses, but were given simultaneously on D4, and sacrificed on D5. The mice that received second doses of 25.0 ng E were sacrificed on D6. The minimum dose of E required to induce uterine receptivity for implantation is a single dose of 50.0 ng E. The uterus remained refractory following short receptive period at E doses lower than 50.0 ng, which is just sufficient to establish desired uterine receptivity. However, repeated administration of sub-threshold doses of 25.0 ng of E could also not effectively sustain uterine receptivity towards successful implantation.
雌激素和孕激素协同和/或分别使胚泡发育、子宫预处理以及诱导着床的接受性等不同事件同步发生。与高着床失败率形成对比的是，关于子宫着床接受性的机制概念仍然难以捉摸。本研究旨在确定在双侧卵巢切除（BLO）并用孕激素预处理的小鼠子宫中，诱导成功着床所需的子宫接受性的最低雌二醇（E）剂量。交配后精子呈阳性的成年雌性小鼠被分为两组。两组均在交配后第4天（D4）通过BLO诱导延迟着床。第1组从D5开始直至处死，每天接受2mg孕激素（P），并在D7注射3.0、10.0、25.0和50.0ng的E。在D8，该组除了在D8接受第二剂25.0ng E并于D9处死的小鼠外，所有小鼠均被处死。第2组遵循相同剂量，但在D4同时给予，并于D5处死。接受第二剂25.0ng E的小鼠于D6处死。诱导子宫着床接受性所需的最低E剂量是单剂量50.0ng E。在低于50.0ng的E剂量下，子宫在短暂的接受期后仍不敏感，而50.0ng E刚好足以建立所需的子宫接受性。然而，重复给予阈下剂量的25.0ng E也不能有效地维持子宫对成功着床的接受性。
