Immunohistochemical localization of basic fibroblast growth factor within the mouse uterus

Uterine samples were either rapidly frozen in liquid nitrogen or placed in Bouin's fixative. A commercial primary polyclonal antibody made in rabbits against human recombinant basic fibroblast growth factor (bFGF) was used. Western blot analysis indicated that the antibody was specific for bFGF and did not react with acidic FGF. The primary antibody was followed by either goat anti-rabbit immunoglobulin G (IgG) conjugated to the fluorescent phycobiliprotein tracer phycoerythrin or biotinylated goat anti-rabbit IgG and a biotin-avidin-peroxidase complex. Specificity controls using adjacent sections were carried out by (i) substituting normal rabbit sera for the primary antisera, (ii) omitting the primary antisera or (iii) extracting sections with NaCl (2 mol l-1) prior to the immunochemical procedures. No binding of the antibody was observed with any of the specificity control sections. The connective tissue stroma and the basal lamina associated with uterine glandular and surface epithelial layers were positive for bFGF. Localization was not observed within surface or glandular epithelial cells. The basal lamina and endothelial cells associated with blood vessels within the uterus and the smooth muscle cells of the myometrium were positive for bFGF. There were no differences in uterine localization patterns or intensity during the oestrous cycle or after ovariectomy and steroid hormone supplementation. These studies demonstrate the specific localization of bFGF within the mouse uterus.