Effect of hangeshashinto on wound healing in hamster 5-fluorouracil-induced oral mucositis model with increased keratinocyte migration and reduced inducible prostaglandin E2.

Abstract

432 Background: Chemotherapy-induced oral mucositis (COM) is common, but optimal treatment is not established. COM is characterized by prolonged damage with painful inflammation that involves pathological pain-evoking prostaglandin E2 (PGE2). We previously found that hangeshashinto (HST), a Japanese herbal medicine, was effective as a gargle for the treatment of COM and also reduced ulcer healing time in patients with grade 2 or worse COM by half in a randomized, placebo-controlled, double-blind clinical trial. However, little is known regarding the mechanisms underlying the anti-COM response elicited by HST. Thus, the aim of this study was to clarify the effects of HST on cell migration and PGE2 system. Methods: COM was induced in hamsters by a combination of 5-fluorouracil administration and mild abrasion of the cheek pouch, and healing was examined by measuring lesion size. Hamsters were given a diet containing 2% HST or a control diet throughout the experiments. To estimate the direct effects of HST, human oral keratinocytes (HOK) were used to assay migration and PGE2 production. Migration was evaluated 9–24 h after scratch wounding using sterile pipette tips. PGE2 was induced by addition of 10 ng/mL interleukin-1β, and the amount of PGE2 in 6 h culture fluids were measured by EIA. Results: Cheek pouch lesions induced by abrasion were aggravated by 5-fluorouracil. Lesions were significantly smaller in the HST group than in the control group. Migration of HOK was time-dependently increased by HST (30–100 µg/mL). Inducible PGE2 production was reduced by HST without cytotoxicity, while constitutive PGE2 was unchanged. Gene expressions of cyclooxygenase-2, phospholipase A2, and prostaglandin E synthase were down-regulated by exposure to HST, but cyclooxygenase-1 was not affected. Screening tests for active ingredients showed that berberine promoted scratch wound closure in HOK, and that gingerols, shogaols, and flavonoids significantly decreased PGE2. Conclusions: Our data suggest that the anti-COM mechanisms of HST involve the acceleration of wound healing in hamster COM model and inhibition of inducible PGE2 production in HOK.