Preventive Effects of a Kampo Medicine, Hangeshashinto on Inflammatory Responses in Lipopolysaccharide-Treated Human Gingival Fibroblasts

Abstract

In the present study, we investigated the effects of a Kampo medicine hangeshashinto (TJ-14) on the production of prostaglandin E2 (PGE2), interleukin (IL)-6 and IL-8 by human gingival fibroblasts (HGFs) treated with lipopolysaccharide (LPS) from Porphyromonas gingivalis. HGFs proliferation was dose-dependently decreased with hangeshashinto at days 3 and 7. However, treatment with LPS (10 ng/ml), hangeshashinto (up to 1 mg/ml) and their combinations for 24 h did not affect the viability of HGFs. Hangeshashinto dose-dependently suppressed LPS-induced PGE2 production but did not alter basal PGE2 level. Hangeshashinto weakly decreased LPS-induced IL-6 and IL-8 productions. Hangeshashinto decreased cyclooxygenase (COX)-1 and COX-2 activities to approximately 60% at 1 mg/ml. Hangeshashinto decreased cytoplasmic phospholipase A2 (cPLA2) expression and LPS-induced COX-2 expression but not affected annexin1 expression. Hangeshashinto weakly suppressed LPS-induced extracellular signal-regulated kinase (ERK) phosphorylation, which is known to lead to ERK activation and cPLA2 phosphorylation. These results suggest that hangeshashinto decreased PGE2 production by (1) suppression of cPLA2 and LPS-induced COX-2 expression, and to a lesser extent, (2) inhibition of COX-2 activity and (3) inhibition of cPLA2 phosphorylation and its activation via inhibition of ERK phosphorylation. Moreover, it is also suggested that hangeshashinto may be useful to improve gingival inflammation in periodontal disease.