Non-identical distribution pattern of epidermal growth factor and platelet-derived growth factor in the mouse uterus during the oestrous cycle and early pregnancy

In the present study, we examined by immunohistochemistry the cell-specific distribution of epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) in the mouse uterus during the oestrous cycle and throughout the first 7 days of pregnancy. Paraffin-embedded tissue samples were immuno stained using the avidin-biotin peroxidase technique and then examined by l ight microscopy. Our results showed that immunostaining for EGF was detecte d in the stroma but not in the luminal or glandular epithelium. A high conc entration of EGF was detected in the stroma around the time of embryo impla ntation at days 3, 4 and 5 of pregnancy. The implanted embryo at day 7 of g estation showed immunostaining for EGF between the ectoderm and endoderm la yers. The cell distribution pattern for PDGF was found to be different from that observed with EGF. Luminal and glandular epithelia displayed PDGF imm unostaining throughout the first 7 days of pregnancy, with the highest inte nsity at days 4 and 5 of gestation. In contrast, no immunostaining was obse rved in the luminal and glandular epithelia at post-oestrus, dioestrus and pro-oestrus stages. However, a weak reaction started to appear at oestrus. The embryo at the blastocyst stage displayed a strong immunoreaction for an tibody against PDGF. In addition, the decidual boundary zone surrounding th e implanted embryo at days 5, 6 and 7 of gestation also showed an immunosta ining for PDGF. The present observations demonstrate clearly the presence o f EGF and PDGF in the mouse uterus in high concentrations at the peri-impla ntation period. Thus, our results, together with what is known about the ef fect of EGF and PDGF in controlling the growth, differentiation and activat ion of a variety of cell types, suggest a possible role for these growth fa ctors during the preparation of the endometrium for implantation in control ling the proliferation activity of stromal and/or epithelial cells. (C) 199 8 Chapman & Hall.