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

Abstract

In the present study, we investigated the effects of a Kampo medicine Orento (TJ-120) on the production of prostaglandin E(2) (PGE(2)), interleukin (IL)-6 and IL-8 by human gingival fibroblasts (HGFs) treated with lipopolysaccharide from Porphyromonas gingivalis (PgLPS). HGFs proliferation was dose-dependently decreased with Orento at days 3 and 7. However, treatment with PgLPS (10 ng/ml), Orento (up to 1 mg/ml) and their combinations for 24 h did not affect the viability of HGFs. Orento suppressed PgLPS-induced PGE(2) production in a dose-dependent manner but did not alter basal PGE(2) level. In contrast, Orento did not alter PgLPS-induced IL-6 and IL-8 productions. These alterations by Orento were similar to those by a mitogen-activated protein kinase kinase (MAPKK/MEK) inhibitor, PD98059. A Orento showed no effect on cyclooxygenase (COX)-1 and COX-2 activities, and increased cytoplasmic phospholipase A(2) (cPLA(2)) expression and increased PgLPS-induced COX-2 expression. Orento suppressed PgLPS-induced mobility retardation of cPLA(2) band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gels, that is cPLA(2) phosphorylation and its activation, while Orento alone did not alter cPLA(2) phosphorylation. Orento suppressed PgLPS-induced extracellular signal-regulated kinase (ERK) phosphorylation, which is known to lead to ERK activation and cPLA(2) phosphorylation. These results suggest that Orento decreased PGE(2) production by inhibition of cPLA(2) phosphorylation and its activation via inhibition of ERK phosphorylation, and also that Orento may be useful to improve gingival inflammation in periodontal disease.