Tumor Necrosis Factor-a and its Receptors, p55 and p75, in Gingiva of Adult Periodontitis

Abstract

Tumor necrosis factor-a. (TNF-a), a pro-inflammatory cytokine, can stimulate matrix metalloproteinase synthesis and osteoclastic bone resorption. We hypothesized that elevated expression of TNF-a and its p55 and p75 receptors (TNF-R) in gingival tissue might associate with periodontitis. Immunohistochemistry was used for the study of the localization of TNF-a and its p55 and p75 TNF-R in adult periodontitis (AP) gingival tissue, in comparison with that in healthy control specimens. TNF-a and p55 TNF-R were detected in sulcular epithelial basal cells and in monocyte/macrophages, fibroblasts, and endothelial cells in the AP gingival tissue specimens, but mainly in fibroblasts and endothelial cells in control specimens. P75 TNF-R was occasionally found in monocyte/macrophage-like cells in gingival tissue specimens. The percentage of TNF-a-containing cells was not increased in AP compared with controls (13.2% ± 6.1% vs. 12.8% ± 7.6%), but, due to the increased cellularity of AP samples, the number of TNF-a positive cells/mm2 was clearly increased (1621 ± 663 vs. 664 ±191, p > 0.001). Thus, AP gingival tissue has an elevated expression of TNF-a and especially its p55 receptor, suggesting that TNF-a may contribute to tissue degradation in periodontitis.