Immunohistochemical demonstration of prostaglandins E2, F2 alpha, and 6-keto-prostaglandin F1 alpha in rat dental pulp with experimentally induced inflammation.

Using formalin-fixed and EDTA-decalcified cryostat sections, the immunohistochemical localization of prostaglandin (PG) E2, PGF2 alpha, and 6-keto-PGF1 alpha (a stable metabolite of PGI2) was examined in normal rat and inflamed dental pulp. Inflammation was induced by opening the pulp chamber. There was no immunoreactivity for prostaglandins in normal dental pulp, whereas positivities for PGE2, PGF2 alpha, and 6-keto-PGF1 alpha were demonstrated in the cytoplasm of macrophages and endothelial cells in the inflamed dental pulp. In addition to these cells, numerous pulp cells and odontoblasts existing in the inflamed pulp and its apical noninflamed area also were intensely stained for PGF2 alpha. Such an area with positive cells gradually extended in an apical direction with the progression of inflammation. These findings suggested that PG production from these host cells is involved in development of inflammation of rat dental pulp.