ANALYSIS OF THE EXPRESSION OF GROWTH-FACTOR, INTERLEUKIN-1, AND LACTOFERRIN GENES AND THE DISTRIBUTION OF INFLAMMATORY LEUKOCYTES IN THE PREIMPLANTATION MOUSE OVIDUCT

The oviduct provides the environment in which fertilization of the egg and subsequent development of the preimplantation mouse embryo occurs , but little is known about the oviduct's capacity to produce growth f actors or cytokines that may influence these preimplantation events. N orthern blot analysis and/or immunohistochemistry were employed to exa mine the expression or cellular distribution, respectively, of the gro wth factors heparin-binding epidermal-like growth factor (HB-EGF), tra nsforming growth factor (TGF)alpha, epidermal growth factor (EGF), ins ulin-like growth factor-I (IGF-I), TGF beta(1), TGF beta(2), and TGF b eta(3); of estrogen-regulated lactoferrin (LF); and of the cytokines i nterleukin (IL)-1 alpha and IL-1 beta in the mouse oviduct during the preimplantation period (Days 1-4 [Day 1 = vaginal plug]) and 7 days af ter ovariectomy. The results demonstrated that, except for EGF, each o f the growth factors and the LF genes are expressed in the ampulla and isthmus regions of the oviduct throughout the preimplantation period. Prominent immunostaining in secretory epithelial cells was noted for HB-EGF, TGF alpha, IGF-I, TGF beta(1), and TGF beta(2), and LF. Less i ntense immunostaining in the serosa and/or smooth muscle was also note d for TGF alpha, IGF-I, and TGF beta(1),. In contrast, intense immunos taining in smooth muscle was noted for TGF beta(2), and TGF beta(3) wa s detected exclusively in smooth muscle cells. The abundance of these mRNAs was relatively constant during the preimplantation period, and o variectomy did not reduce the levels of these mRNAs. In contrast to th ese growth factors, the cytokine mRNAs examined (IL-1 alpha and IL-1 b eta) were at or below the limits of detection under these experimental conditions, and inflammatory leukocytes (LF-immunopositive neutrophil s, IL-1 beta-immunopositive monocytes/macrophages, or peroxidase-posit ive eosinophils) were not detected in the oviduct, but were abundant i n the adjacent uterine stroma on Day 1. These studies show that severa l growth factors are synthesized by the mouse oviduct and suggest that ovarian steroids do not play a major role in modulating expression of these genes in the oviduct during the preimplantation period. Further more, unlike the uterus on Day 1, the oviduct does not exhibit an infl ammatory response to mating.