| As one of the most common diseases, infertility occurred about 10-25% of incidence rate among couples. Even undergone through systemic investigation, there are still 10% of them who could not find the cause of their failure to conceive pregnancy, which is called unexplained infertility. Among various reasons, the failure of implantation becomes an important cause of consideration.The fine regulation between embryo and maternal environment is required for the success of embryo implantation and pregnancy establishment. The development of embryo and endometrium must be synchronized, and uterine receptivity is critical. Only within the implantation window phase, endometrium accepts the embryo implantation, otherwise it rejects embryo. Embryo implantation involves a series of cellular or molecular events, requiring various modulating factors, among which, including integrins and MMPs.Integrins form a great family of heterodimeric transmembrane protein receptors, consists of two subunits, and . They serve as receptors of ECU, mediate the interaction of cell to cell and the adhesion of cell to extracellular matrix, involving various physiological processes. Human endometrium can also express integrins and their distribution has cycle- and cell- specific, v 3 is a special integrin. It appears abruptly after 20 days of the normal menstrual cycle. Theincreased a vfl 3 expression is coincident with a putative "implantation window" . It is a marker of endometrium receptivity. The expression of avP3 is reduced in the endometrium of women with luteal phase deficiency, hydrosalpinx, mild endometriosis and unexplained infertility.The MMPs form a family of structurally related, zinc-dependent endopeptidases that involve in the degradation of extracellular matrix (ECU) and basement membranes (BM). These enzymes and their tissue inhibitors (TIMPs ) play a critical role in normal tissue-remodeling processes, including embryonic growth, development and implantation. Among MMPs, the 92-Kda type IV collagenase (MMP-9, gelatinase B) is a very important enzyme for BM degradation, capable of degrading virtually all components of the ECM, such as collagens, proteoglycans, and glycoproteins. MMP-9 degrades a variety of substrates, particularly collagen type IV and V. Many studies have found that MMP-9 in glandular epithelial cells of endometrium was greatest during the late proliferative phase and just after ovulation; its presence in glandular secretion and the uterine fluid was optimal during the peri-implantation phase. It is possible that this enzyme might be functional in processing specific components of the uterine fluid, thereby contributing to the recognition processing required for blastocyst implantation.TIMPs are the natural inhibitors of all MMPs called tissue inhibitors of metalloproteinases of which four have been described. The TIMPs bind with high affinity and 1 : 1 molar ratio to active MMPs resulting in the loss of proteinase activity. TIMP-1 is the main inhibitor of MMP-9. The secretion of TIMP-1 is increased during peri-implantation phase accompanying with increased secretion of MMP-9. The TIMP-1 which can inhibit the activity of MMP-9 is the important regulator of ECM remodeling, and can limit the extent of trophoblast invasion. It is important for normal embryo implantation.In this study, 18 patients with the diagnosis of unexplained infertility weredesigned to the study group. The mean duration of their infertility was 3.81 2. 73 years ( range 2-10 years ). Of these patients 11 had primary infertility and 7 had secondary infertility. 15 women with normal fertility were selected as fertile controls. Measurement of BBT daily was requested. Ovulation was considered to have occurred when there was a temperature rise of 0.5 , for 12 days immediate preceding a menstruation period. Six to nine days after the onset of BBT ascending, venous blood 'samples were collected and the endometrial biopsies were performed. The blood serum and the tissue were both stored at the -80 . Serum E2...
|
PDF Full Text Request