Rebamipide affects the efficiency of colchicine for the herpes simplex virus-induced inflammation in a Behcet's disease mouse model

Abstract

Rebamipide inhibits free radicals derived from activated neutrophils and decreases the inhibiting inflammatory cytokine. Behcet's disease (BD) is a chronic, multi-systemic inflammatory disorder with arthritic, gastrointestinal, mucocutaneous, ocular, vascular, and central nervous system involvement. This disease has a chronic course with periodic exacerbations and progressive deterioration. To study the effect of rebamipide treatment to BD-like mice, combination treatment with rebamipide and colchicine was compared to colchicine treatment. Colchicine is one of the most frequently prescribed medicine to the patients with BD. For each BD mouse, 200 μl gastric fluid or 2 μg colchicine or 150 μg rebamipide or 2 μg colchicine plus 150 μg rebamipide was treated orally once per day. Treatment was done for 5 consecutive days. Two hour or 20 days after last administration, spleens were isolated for RT-PCR and real time PCR, and serum was collected for ELISA. In the combination treated group, TNF alpha, MIP-1 alpha, p22 phox, p47 phox, and gp91 phox mRNA expressions were lower than rebamipide treated or colchicine treated groups by reverse transcriptase PCR. NADPH oxidase subunits mRNA were markedly downregulated compared to the colchicine treated group by real time PCR. At 20 days after administration, combination treatment decreased 23.5% of the severity score compared to before administration. In contrast, colchicine treatment decreased 14.3% of the severity score compared to before administration. Rebamipide helped the function of colchicine to improve the HSV induced BD-like symptoms by inhibiting the expression of NADPH oxidase in vivo mouse model.

Introduction

Major pharmacological actions of rebamipide {2- (4-chlorobenzoylamino) -3- [1,2-dihydro-2-oxo-4-quinolyl] propionic acid}, has a protective effect against hydrogen peroxide-induced hemorrhagic mucosal lesions in rat stomach (Sakurai and Yamasaki, 1994), attenuates Helicobacter pylori induced gastric mucosal cell injury associated with neutrophil derived oxidants (Suzuki et al., 1994), increases endogenous prostaglandins biosynthesis mediates gastroprotective effect (Kline et al., 1993), reduces and scavenges hydroxyl radical (Naito et al., 1995), and suppresses gastric mucosal inflammation (Sakurai et al., 2005, Fujioka et al., 2003). Pharmacological action of rebamipide is a partial agonist for Ca²⁺-mobilizing action, and it is also an antagonist for the amylase-releasing action of cholecystokinin (Moon et al., 2004). Rebamipide inhibits free radicals derived from activated neutrophils (Sakurai et al., 2005, Shimoyama et al., 2003), and decreases the susceptibility of gastric mucosa to acid-induced injury by inhibiting neutrophil activation (Harada et al., 2005). Rebamipide treatment reduced inflammation in dextran sulfate sodium induced colitis by inhibiting inflammatory cytokine mediated neutrophil infiltration in the colon (Kishimoto et al., 2000).

Behcet's disease (BD) is a chronic, multi-systemic disorder with arthritic, gastrointestinal, mucocutaneous, ocular, vascular, and central nervous system involvement. This disease has a chronic course with periodic exacerbations and progressive deterioration (Shimizu, 1979). The etiology of BD is unclear, but viral infection has long been postulated as one of the main factors. Since Hulusi Behcet first proposed a viral etiology (Behcet, 1937), the viral hypothesis has been verified by detection of virus in saliva (Lee et al., 1996a), intestinal ulcers (Lee et al., 1993), and genital ulcers (Lee et al., 1996b, Bang et al., 1997a) of patients with BD. Subsequent to this finding, herpes simplex virus (HSV) inoculation of the earlobes of ICR mice resulted in the development of BD-like symptoms (Sohn et al., 1998). Manifestations in mice after HSV inoculation included multiple symptoms such as oral ulcers, genital ulcers, skin ulcers, eye symptoms, gastrointestinal ulcers, arthritis, and neural involvement, as well as skin crusting. The frequency of these symptoms was similar to that of patients with BD (Kim et al., 1988).

Abnormalities of neutrophils have been suggested to be responsible for many of the clinical manifestations of BD (Sahin et al., 1996) and serum of BD enhances superoxide production of normal neutrophils (Yoshida et al., 1998). According to the results of Matsuda et al. (2003), rebamipide improves the aphthae count and pain score in BD patients. They suggested that it may therefore be useful in the treatment and prevention of frequently recurrent oral aphthous ulcers of BD. Hahm et al. (1998), reported that combination therapy, including lansoprazole, amoxicillin, and rebamipide, against H. pylori augmented eradication rates of H. pylori with decreasing the changes of oxidative stress and cytokines. Also in Behcet's disease, Bang (1997b) reported that combination-agent regimen is more effective than a single-agent regimen in the treatment of patients with Behçet's disease. Colchicine is one of the most frequently prescribed medicine to the patients with Behcet's disease (Kaklamani and Kaklamanis, 2001). In this study, we used a rebamipide combination with colchicine to reduce inflammation in BD-like mice in vivo and to reduce superoxide-producing enzyme, NADPH oxidase subunit, and to increase the effect of anti-inflammation accompanying with cytokine or chemokine expression, thereafter improving BD symptoms in mice.