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 factors or cytokines that may influence these preimplantation events. Northern blot analysis and/or immunohistochemistry were employed to examine the expression or cellular distribution, respectively, of the growth factors heparin-binding epidermal-like growth factor (HB-EGF), transforming growth factor (TGF) a, epidermal growth factor (EGF), insulin-like growth factor-I (IGF-I), TGFP,, TGF,I2, and TGF03; of estro-gen-regulated lactoferrin (LF); and of the cytokines interleukin (IL)-Ia and IL- 13 in the mouse oviduct during the preimplantation period (Days 1-4 [Day 1 = vaginal plug]) and 7 days after ovariectomy. The results demonstrated that, except for EGF, each of the growth factors and the LF genes are expressed in the ampulla and isthmus regions of the oviduct throughout the preim-plantation period. Prominent immunostaining in secretory epithelial cells was noted for HB-EGF, TGFat, IGF-I, TGF,I, and TGF[, and LF. Less intense immunostaining in the serosa and/or smooth muscle was also noted for TGFa, IGF-I, and TGFD,. In contrast, intense immunostaining in smooth muscle was noted for TGF,I2, and TGFB3 was detected exclusively in smooth muscle cells. The abundance of these mRNAs was relatively constant during the preimplantation period, and ovariectomy did not reduce the levels of these mRNAs. In contrast to these growth factors, the cytokine mRNAs examined (IL-la and IL-1l) were at or below the limits of detection under these experimental conditions, and inflammatory leukocytes (LF-immunopositive neutrophils, IL