The antibody-neutralisation of PDGF, CSF-1, TGFb2,3, EGF and EGF-receptor in utero in pre-implantation mice

Gene expression of leukemia inhibitory factor (LIF) and macrophage colony stimulating factor (M-CSF) in bovine endometrium during early pregnancy

Leukemia inhibitory factor (LIF) and macrophage colony stimulating factor (M-CSF), members of the group of hemopoietic cytokines, play a primary role in the control of embryo development and implantation and in the growth of the placenta in humans and mice. Gene expressions of LIF and M-CSF were investigated using quantitative RT-PCR in bovine endometrial tissues during early and mid-pregnancy (Days 16-17, 20-21, 30-36, 48-49 and 74-140) and during the estrous cycle (Days 13-14). Leukemia inhibitory factor and M-CSF genes were expressed in all samples examined. Significant differences were found between the gene expression patterns of LIF and M-CSF. Leukemia inhibitory factor expression level at Days 48-49 was the highest in caruncular endometrium, however, the large variability negated any significant differences. Leukemia inhibitory factor expression levels in intercaruncular endometrium at Days 48-49 and 74-140 of pregnancy were greater than at Days 13-14 of the estrous cycle and at other days of pregnancy. No significant change was recognized in M-CSF expression levels in caruncular endometrium. Macrophage colony stimulating factor expression level in intercaruncular endometrium at Days 74-140 was greater than those of the other samples. These results suggest that LIF and M-CSF are produced in the endometrium and may play different roles in early and mid-pregnancy.

Temporal changes in the expression of platelet-derived growth factor and fibronectin in the uterine epithelium during early pregnancy

In rat uterine epithelium, platelet-derived growth factor (PDGF) and fibronectin (FN) display changes in temporal expression during implantation. PDGF was expressed in the apical epithelium on Day 3, apically, laterally and basally at the time of implantation on Day 6 but was not expressed on Day 7. FN expression was not seen until Day 6, when it was expressed only in the basement membrane. However, this label was markedly increased in the basement membrane on Day 7. We suggest that fibronectin may be upregulated by PDGF in preparation for invasion of the basement membrane by stromal decidual cells and the subsequent attachment of the trophoblast to the maternal extracellular matrix.

Premature implantation may be prevented by an inhibitory system regulated by epidermal growth factor

Using immunohistochemical methods at both light and electron microscopical levels, we have studied epidermal growth factor in the uterine epithelium during early pregnancy and up to the time of blastocyst implantation. We report that the distribution of this growth factor changed markedly over the period of study and that it was gradually de-expressed across the entire uterine epithelium as pregnancy advanced towards the time of implantation. At the electron microscopical level, immunogold labelling clearly showed label associated with both lateral and basal plasma membranes very early in pregnancy but not by the time of implantation. We suggest that the de-expression of this molecule may indicate its role in the removal of mechanisms which inhibit uterine receptivity for implantation.