Effect of DHU001, a Polyherbal Formula on Formalin-induced Paw Chronic Inflammation of Mice

Abstract

The effect of DHU001, a mixed herbal formula consisted of 7 types aqueous extracts for various respiratory disorders were evaluated on the formalin-induced paw chronic inflammation in mice after oral administration. Mice were subaponeurotically injected in the left hind paw with 0.02 ml of 3.75% formalin, then subjected to 500, 250 and 125 mg/kg of DHU001 oral administration, once a day for 10 days during which then the hind-paw thickness and volume were measured daily. The paw wet-weight, histological profiles, histomorphometrical analyses and paw tumor necrosis factor (TNF)-α contents were conducted at termination. After two formalin treatments, a marked increase in the paw thickness and volume was detected in the formalin-injected control as compared with that in the intact control, plus at the time of sacrifice the paw wet-weights, paw TNF-α contents were also dramatically increased with severe chronic inflammation signs at histopathological observations. However, these formalin-induced chronic inflammatory changes were dramatically decreased by treatment of dexamethasone and all three different dosages of DHU001. DHU001 has favorable effects on formalin-induced chronic inflammation mediated by TNF-α suppression, and DHU001 may represent an alternative approach for the treatment of chronic inflammatory diseases.

Keywords: Chronic Inflammation; DHU001; Mouse; Polyherbal Formula; Tumor Necrosis Factor.

Fig. 1.. Body weights detected during 10 days of continuous oral treatment periods of DHU001 in formalin-induced chronic inflammation mice. No meaningful changes on the body weights were detected in all administrated groups as compared with intact or formalin controls, respectively except for dexamethasone-treated mice in which significant decreases on the body weights were detected from 5 days after administration as compared with intact and formalin control. Values are expressed mean ± S.D. of eight mice. Before means 1 day before first formalin treatment or start of test material administration. Subaponeurotic injection of formalin was conducted at Day 0 and Day 3, respectively (arrows). All animals were overnight fasted at Day 0 and sacrifice. ^ap < 0.01 and ^bp < 0.05 as compared with intact control; ^cp < 0.01 and ^dp < 0.05 as compared with Formalin control.

Fig. 2.. The representative histological profiles of dorsum pedis skin: observed in vehicle control (A, B), formalin-injected control (C, D), and dexamethasone (E, F), DHU001 500 (G, H), 250 (I, J), and 125 (K, L) mg/kg treated groups. Note that histopathological changes related to chronic inflammation, such as severe fibrosis, the formation of necrotic debris, and infiltration of inflammatory cells, were observed in the dorsum pedis skins of the formalin-injected control, leading to the hypertrophy of subcutaneous regions. However these histopathological changes were dramatically decreased by treatment with dexamethasone and at all three different dosages of DHU001 as compared with the formalin-injected control. The arrow indicates the thickness of dorsum pedis skin. Ep, epithelium – keratinized stratified squamous epithelium; Se, sebaceous gland; H&E stain; Scale bars = 160 μm.

Fig. 3.. The representative histological profiles of dorsum digit skin: observed in vehicle control (A, B), formalin-injected control (C, D), and dexamethasone (E, F), DHU001 500 (G, H), 250 (I, J), and 125 (K, L) mg/kg treated groups. Note that histopathological changes related to chronic inflammation, such as severe fibrosis, the formation of necrotic debris, and infiltration of inflammatory cells, were observed in the dorsum digit skins of the formalin-injected control, leading to the hypertrophy of subcutaneous regions. However these histopathological changes were dramatically decreased by treatment with dexamethasone and at all three different dosages of DHU001 as compared with the formalin-injected control. The arrow indicates the thickness of dorsum digit skin. Bo, metatarsal bones; Ep, epithelium – keratinized stratified squamous epithelium; H&E stain; Scale bars = 160 μm.