| Research Abstract |
We proposed on the basis of our own observations in rats and mice that macrophages may be functionally involved in the embryomaternal interactions during the peri-nidatory period in eutherian mammals (Tachi et al., 1981, 1986). Recently, much interest has been focused upon the possible role played by the phagocytes during early gestation. We improved method for the culture of macrophages in vitro (Tachi, 1988), and, at the same time, developed a new method for culture of mouse blastocysts in vitro suitable for quantitative analysis (Tachi, 1991, 1992). Using these methods we found that the macrophage-conditioned medium stimulate highly the proliferation of cells in the ectoplacental cone (EPC in the following) of the cultured blastocysts (Tachi, 1991). The effective substance(s) contained in the macrophage-conditioned medium is probably below 30,000 in molecular weight, and differ from EGF or FGF. It was reported that IGF-1 stimulates the proliferation of EPC cells of the placenta isolated from mice of 10.5 Day of pregnancy (Kanai-Azuma, 1992). However, the effects of IGF-1 on the EPC cells of the cultured blastocysts are at present not so conspicuous. While the present research projects were in progress, GM-CSF (Athanassakis et al., 1991) and IL-3 (Mori et al., 1992) were reported to stimulate the EPC cell proliferation. Furthermore, M-CSF were found to play important roles in implantation of mouse embryos, by mediating certain crucial processes in the endometrium (Pollard et al., 1992). Since IL-3, GM-CSF and M- CSF are well know monokines, it may be said that the importance of the monokines in the implantation of muridae rodents are being gradually elucidated in the literature. Although it was not possible to finally identify the molecular nature of the substance(s) in the macrophage-conditioned medium, the research efforts are still continued in our laboratory.
|
