| Successful implantation includes steps of recognition, location, adhesion, penetrating, and finally implanted into endometrial matrix. During this process, both embryo and endometrium undergo synergetic adaptation in time and space. The result is that on one side, embryos gradually develop, mature, and get into an "invasive state"; on the other side, the endometrium turns into "receptive state". Thus, the synergetic adaptation is crucial for successful implantation. Moreover, it is also a target site by which the implantation is regulated.The recent study shows that except for the fine regulation of estrogen and progesterone on embryo and endometrium, both embryo and endometrium themselves can secrete many kinds of protein factors, such as LIF(leukaemia inhibitory factory), EGF(epidermal growth factor), MMPs(matrix metalloproteinases), and et al. These protein factors act as autocrine or paracrine manner to co-regulate the specific physiological state of pragnance. It is indicated that the expression and secretion levels of certain kinds of protein factors are closely related to the growth, development, and implantation capability. Thus, the levels of implantation-related factors may be a practical functional marker in evaluating the developmental state, implantation capability, as well as the receptivity of endometrium.The functions of insulin-like growth factor (IGF) family during implantation have been studied. The members of IGF family include IGF(IGF-I and IGF-II), IGF receptor(IGF-IR and IGF-II/M6P-R), and IGF binding proteins(IGFBPs). Among which, IGF-II and IGF-II/ M6P-R are highlighted during peri-implantation period. IGF-II plays important roles in promoting proliferation, differentiation and mitogenesis of the cells, as well as accelerating the growth, metastasis and anti-apoptosis of tumor cells. It is reported that IGF-II is the only autocrine factor in IGF family during implantation. The action of IGF-II is mediated by IGF-IR and IGF-II/M6P-R. It is recognized that the role of IGF-II/ M6P-R is to clear the overexpressed IGF-II; hence, exerting negative regulation on IGF-II by which controlling the cell proliferation and differentiation. The reported results about the expression of IGF-II in embryos of mouse are not parallel.Our previous work has shown that oligosaccharide LeY [Fuc (1,2- Gal (1,4 (Fuc (1,3)- GlcNAc(1 -3Gal] on surface of embryo was expressed stage specifically, and had important functions in mediating molecular recognition between embryo and endometrium. Some of the results indicate that LeY, possibly a messenger molecule, participates the regulatory network of implantation by controlling the expression of other implantation –related factors. The major work in the dissertation is as follows:1.Using RT-PCT, dot immunoblot and indirect immunofluorescent assay to study the gene expression of IGF-II and IGF-II/M6P-R, the protein expression of IGF-II during embryos of different stages (2-cell, 4-cell, 8-cell, morula, and blastocyst), as well as the distribution of IGF-II. The results showed that: (1) The expression of IGF-II was increased with the time course of embryo development, and reached to its peak value at blastocyst stage; (2) The expression of IGF-II/M6P-R was decreased gradually during the developmental process, and got the lowest level at blastocyst stage; (3) The analysis of indirect immunofluorescent assay showed that no obvious signal was found at zygote, and the signal was observed from 2-cell embryo, and got more intense with developmental process. The peak value occurred at blastocyst stage. 2.The expression of IGF-II in endometrium of different pregnant stage (D1, D2, D3, D4, and D5) was analyzed by RT-PCR and dot immunoblot. The results showed that gene and protein expression was similar with the levels increased from early stage (D1, D2, D3), reached their highest values at "implantation window"(D4), and then dropped sharply on D5. It indicated that IGF-II may be a functional marker used for judging the endometrial receptivity. 3.A...
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