Immunohistochemical localization of platelet-derived growth factor receptors in the porcine uterus during the oestrous cycle and pregnancy.

Abstract

The distribution of alpha- and beta-type receptors for PDGF was studied immunohistochemically in the uterus of cycling and pregnant pigs with well-documented hormonal status in order to determine a possible steroid hormone-dependence of its expression. Peroxidase-antiperoxidase (PAP) labelling at light microscopical level was done with rabbit polyclonal antisera recognizing either both alpha- and beta-type receptors (PDGFR-1), or selectively beta-type (PDGFR-3). Immunoreactivity to the PDGF-receptors of alpha- and beta-type (PDGFR-1) was present in all endometrial samples examined, being located principally on subepithelial stromal and endothelial cells, the wall of endometrial blood vessels and in the fetal placenta (trophoblast and adjoining blood capillaries). In the myometrium, the major reactive cells were the non-vascular smooth muscle cells, and to some extent, also those of the tunica media of major uterine vessels. No dramatic variations in the intensity of the reaction were noticed during the oestrous cycle. A very intense immunoreactivity was present at early pregnancy and at term, i.e. under major oestrogenic influence. The immunoreactivity to the PDGF-receptor antiserum R-3 (against beta-type) was similarly localized as that showed for R-1 antiserum, while of a weaker intensity. The results indicate the presence of PDGF receptors (alpha- and beta-type) in the endo- and myometrium of cycling and pregnant pigs, and that their expression seems to be accentuated under oestrogenic influence.