Rebamipide inhibits tumor necrosis factor-α-induced interleukin-8 expression by suppressing the NF-κB signal pathway in human umbilical vein endothelial cells

Therapeutic Effects of Rebamipide Nanocrystals as Carbopol Gel Formulation Containing Gum Arabic in a Hamster Model of Oral Mucositis

Severe oral mucositis is a major cause of a low quality of life in patients; however, the therapeutic effect of traditional treatments is insufficient. Therefore, we designed a carbopol gel based on rebamipide nanocrystals (REB NCs) and gum arabic (GA-REB@NP), and investigated its efficacy in accelerating wound healing in a hamster model of oral mucositis. REB NCs were prepared by bead milling, and GA- REB@NP were prepared by incorporating REB NCs into a carbopol gel. The REB sizes were measured using a SALD-7100 and NanoSight LM10, and both powder X-ray diffraction and differential thermal analysis were used to analyze the crystalline form. Drug release from the gel formulations and therapeutic effects were evaluated using hamsters. The particles of milled-REB without GA were microsized, whereas the particle size of milled-REB with GA was in the range of 30-180 nm, and the crystalline form was similar to that of REB with or without bead milling. Next, we evaluated the characteristics of GA-REB@NP. The particle size of REB in GA-REB@NP was in the range of 45-200 nm, and drug release from GA-REB@NP was higher than that from the gel incorporating REB microcrystals (GA-REB@MP). In addition, REB nanoparticles were released from GA-REB@NP. Moreover, inhibitors of both clathrin- (dynasore) and caveolae-dependent endocytosis (nystatin) attenuated the enhanced REB levels in the cheek pouches of hamsters treated with GA-REB@NP. GA-REB@NP also enhanced the healing of the wound area compared with GA-REB@MP in hamsters injected with acetic acid. We prepared GA-REB@NP, which provided high REB delivery into the cheek pouch tissue via endocytosis. Additionally, we demonstrated that wound healing in acetic acid-injected hamsters was promoted by the application of GA-REB@NP.

[Effect of rebamipide on the acute gouty arthritis in rats induced by monosodium urate crystals]

OBJECTIVE

To investigate the role of rebamipide in the treatment of acute gout arthritis rats induced by monosodium urate (MSU) crystal.

METHODS

Forty-two male rats were randomly divided into three groups (n=14). Group A was treated with oral rebamipide, group B with oral colchicine, and group C with oral placebo. The rats were monitored for the induction of arthritis with clinical manifestations and pathological changes, and the levels of interleukin (IL)-1β、IL-6、IL-10, and tumor necrosis factor (TNF)-α in serum were measured.

RESULTS

In group C, the clinical score and swelling index reached the maximum in 24 h, and then gradually decreased to 72 h. After 24 h of model induced, the clinical scores in group C were significantly higher than those in group A and group B [2 (1-3) vs. 0 (0-1) vs. 1 (0-2), P < 0.01], the swelling indexes in group C were significantly higher than those in group A and group B [0.36 (0.16-0.52) vs. 0.11 (0-0.20) vs. 0.12 (0-0.16), P < 0.01]. Histologically, after 24 h of model induced, there was a large number of neutrophil infiltration in the synovium of group C [scale score: 4 (2-4)], and there was no significant inflammatory cell infiltration in group A [1 (0-2)] and group B [1 (0-2)], the difference was statistically significant (P < 0.001). After 24 h of model induced, the levels of IL-1β, IL-6, IL-10, and TNF-α in serum of group C were significantly higher than those in group A and B [IL-1β: (41.86±5.72) vs. (27.35±7.47) vs. (27.76±5.28) ng/L, IL-6: (1 575.55±167.11) vs. (963.53±90.22) vs. (964.08±99.31) ng/L, IL-10: (37.96±3.76) vs. (21.68±4.83) vs. (16.20±2.49) ng/L, TNF-α: (21.32±1.34) vs. (15.82±2.54) vs. (17.35±7.47) μg/L, P < 0.001].

CONCLUSION

Rebamipide has a protective effect on acute gout arthritis rats induced by MUS crystals.

Intra-articular injection of rebamipide prevents articular cartilage degeneration in murine post-traumatic osteoarthritis models

Objectives: Rebamipide is a protective drug used for gastric mucosal injuries, and it also exerts protective effects for a variety of other tissues. In this study, murine post-traumatic (PT) osteoarthritis (OA) models in vivo and human OA chondrocytes in vitro were used to examine the effects of rebamipide on articular cartilage degeneration.Methods: Male BALB/c mice were used. The knee ligaments were transected in both knees. Mice were injected with rebamipide into the knee joint every week. Human chondrocytes were stimulated with IL-1β, then treated with or without rebamipide. The levels of mRNA expression of COL2A, IL-1β, TNFα, NF-κB, MMP3, MMP13, ADAMTS5, TIMP3, FGF2, and TGFβ were estimated using real-time PCR.Results: Histological scores were significantly better in the rebamipide 1 mg/mL and 10 mg/mL groups than in the control group. Rebamipide up-regulated the mRNA expressions of COL2A, TIMP3, TGFβ, and FGF2 in chondrocytes and down-regulated IL-1β, TNFα, NF-κB, MMP3, MMP13, and ADAMTS5.Conclusion: Intra-articular injection of rebamipide prevents articular cartilage degeneration for 6 weeks in murine models of OA in vivo. Rebamipide down-regulates inflammatory cytokines and catabolic factors and up-regulates anabolic factors in human chondrocytes in vitro. Rebamipide could be an important treatment for prevention of articular cartilage degeneration.

The Efficacy of 2% Topical Rebamipide on Conjunctival Squamous Metaplasia and Goblet Cell Density in Dry Eye Disease

Purpose: To clarify the pharmacological effects of 2% rebamipide eye drops on mucosal membrane functions of the ocular surface epithelium, we investigated keratoconjunctival alterations at the cellular level in this study. Methods: Fifteen patients with definite dry eye disease were recruited from outpatient clinics of the Department of Ophthalmology, Ichikawa General Hospital. The patients received treatment with 2% rebamipide eye drops q.i.d for 12 weeks. Symptom score assessment, tear film breakup time, fluorescein and lissamine green ocular surface vital staining, grading of lid wiper epitheliopathy, Cochet-Bonnet corneal sensitivity, assessment of squamous metaplasia grades, and goblet cell density calculations from conjunctival impression cytology samples, as well as evaluation of nucleocytoplasmic ratios and corneal epithelial cells from in vivo confocal microscopy images before and 3 months after treatment were performed. Results: The mean symptom scores, tear film breakup time values, ocular surface fluorescein and lissamine green vital staining scores, and lid wiper scores showed a significant improvement after treatment (P < 0.01). The mean squamous metaplasia grade also showed a significant improvement (1.2 ± 0.1 → 0.3 ± 0.1) 3 months after treatment (P = 0.004). There were similar significant improvements in the mean corneal epithelial cell density (660.1 ± 62.6 → 1015.5 ± 43.5 cells/mm2) (P = 0.002) and nucleocytoplasmic ratios (0.1 ± 0.0 → 0.2 ± 0.0) (P = 0.0042) after treatment. Conclusions: Topical use of 2% rebamipide for 3 months was associated with improvements in ocular surface differentiation due to changes of mucosal functions at the cellular level. These alterations may explain objective and subjective improvements in dry eye disease.

The Effect of Rebamipide Ophthalmic Solution on Cytokine and Mucin Secretion in Culture of Conjunctival Epithelial Cells From the Cu, Zn-Superoxide Dismutase-1 (SOD-1) Knock-Down Mouse

OBJECTIVES

To evaluate the in vitro effects of 1-mM rebamipide ophthalmic solution on the expression of inflammatory cytokines and MUC5AC in Cu, Zn-superoxide dismutase-1 (SOD-1) knock-down conjunctival epithelium.

METHODS

Conjunctival epithelium from C57BL/6 wild-type mice was cultured and treated with rebamipide ophthalmic solution. Using cytometric bead array, we examined the levels of interleukin-(IL)-6, IL-10, IL-17, monocyte chemoattractant protein-1, interferon-γ (INF-γ), tumor necrosis factor, and IL-12p70 in the culture supernatants. The culture supernatants were obtained from the culture medium of nontreated or SOD-1 knock-down conjunctival epithelium using small interfering RNA (siRNA). In addition, ELISA was performed to ascertain the MUC5AC concentration in the culture medium.

RESULTS

After rebamipide ophthalmic solution was applied, IL-6 concentration in the supernatants of conjunctival epithelial cells treated with and without siRNA showed a significant timewise decrease from 0 to 24 hr (963±42 to 0.07±0.05 pg/mL and 932±168 to 2.2±0.05 pg/mL, respectively) (P<0.001). Compared with baseline values, MUC5AC concentrations significantly increased 24 hr after rebamipide application to the conjunctival cultures-both with and without SOD-1 siRNA treatment (P<0.05 in both cases).

CONCLUSIONS

Rebamipide seems to increase MUC5AC levels and suppress inflammation by decreasing IL-6 levels in mouse conjunctival epithelial cell cultures. SOD-1 siRNA-treated mouse conjunctival epithelial cell culture is a practical method for investigating changes in mucosa-associated mucins and proinflammatory cytokines in response to therapeutic interventions.

Potential Role of Rebamipide in Osteoclast Differentiation and Mandibular Condylar Cartilage Homeostasis

Background:

Temporomandibular joint osteoarthritis (TMJ-OA) is a degenerative disease that involves changes in subchondral bone and progressive degradation of cartilage. Currently, rebamipide, a gastroprotective drug, is administered to protect gastric mucosa and accelerate ulcer healing.

Objectives:

Recent studies have shown that rebamipide also attenuates cartilage degeneration by suppressing oxidative damage and inducing homeostasis of the extracellular matrix of articular chondrocytes. Regarding the latter, reduced expression of cathepsin K, NFATc1, c-Src, and integrin β3, and increased expression of nuclear factor-kappa B, have been found to be mediated by the transcription factor, receptor activator of nuclear factor kappa-B ligand (RANKL).

Methods:

Treatment with rebamipide was also found to activate, mitogen-activated protein kinases such as p38, ERK, and JNK to reduce osteoclast differentiation. Taken together, these results strongly indicate that rebamipide mediates inhibitory effects on cartilage degradation and osteoclastogenesis in TMJ-OA.

Results and Conclusion:

Here, we highlight recent evidence regarding the potential for rebamipide to affect osteoclast differentiation and TMJ-OA pathogenesis. We also discuss the potential role of rebamipide to serve as a new strategy for the treatment of TMJ-OA.

Rebamipide, an Amino Acid Analog of 2(1H)-Quinolinone, Inhibits the Formation of Human Osteoclasts

Objectives. Drug repositioning or drug reprofiling (DR) has recently been growing in importance. DR has a significant advantage over traditional drug development because the repositioned drug has already passed toxicity tests; its safety is known, and the risk of adverse toxicology is reduced. In the current study, we investigated the role of rebamipide, a mucosa-protecting agent, with recently reported anti-inflammatory function, in human osteoclastogenesis. Methods. Peripheral blood mononuclear cells (PBMCs) were cultured in the presence of M-CSF and sRANKL. Osteoclast formation was evaluated by immunohistological staining for CD51/61 (vitronectin receptors). Osteoclast formation, in the presence or absence of rebamipide (0, 1, and 3 mM), was observed by time-lapse photography and actin ring formation. The number of absorption sites and area of absorption were calculated using Osteologic™ plates. Pit formation was studied by 3D-SEM. Results. Rebamipide inhibited human osteoclast formation at 3 mM, a pharmacological concentration, and inhibited resorbing activity dose-dependently. Rebamipide induced the degradation of actin rings in mature osteoclasts. This mechanism may involve inhibiting the osteoclast fusion pathway through reducing the expression of DC-specific transmembrane protein (DC-STAMP). Conclusions. The present study suggests that rebamipide would be useful as a novel agent for osteoporosis and rheumatoid arthritis.

Rebamipide Suppresses Monosodium Urate Crystal-Induced Interleukin-1β Production Through Regulation of Oxidative Stress and Caspase-1 in THP-1 Cells

This study investigated the effect of rebamipide on activation of the NLRP3 inflammasome and generation of reactive oxygen species (ROS) in monosodium urate (MSU) crystal-induced interleukin-1β (IL-1β) production. Human monocyte cell line THP-1 and human umbilical venous endothelial cells (HUVECs) were used to assess the inflammatory response to MSU crystals. NADP/NADPH activity assays were used as a marker of ROS generation. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting were performed to evaluate levels of IL-1β, caspase-1, NLRP3, associated speck-like protein (ASC), nuclear factor-κB (NF-κB), p65, IκBα, intercellular adhesion molecule 1 (ICAM-1), and vascular cell adhesion molecule 1 (VCAM-1). Experimental pharmaceuticals included rebamipide, colchicine, dexamethasone, and ascorbic acid. In THP-1 cells, treatment with MSU crystals increased NADP/NADPH ratios and IL-1β expression, and both of these responses were potently inhibited by addition of rebamipide. Rebamipide also attenuated enhanced expression of caspase-1 gene by MSU crystals (p < 0.05). Western blotting demonstrated that MSU crystals stimulated caspase-1 but not NLRP3 and ASC activation. Similarly, MSU crystals activated the NF-κB pathway, which in turn was blocked by rebamipide. Stimulation of HUVECs with MSU crystals increased expression of VCAM-1 and ICAM-1, which were markedly inhibited by both rebamipide and dexamethasone. This study demonstrated that rebamipide inhibits IL-1β activation through suppression of ROS-mediated NF-κB signaling pathways and caspase-1 activation in MSU crystal-induced inflammation.

Rebamipide retards CCl4-induced hepatic fibrosis in rats: Possible role for PGE2

Prostaglandin E2 (PGE2) is a potent physiological suppressor of liver fibrosis. Because the anti-ulcer drug rebamipide can induce the formation of endogenous PGE2, this study investigated the potential effects of rebamipide on development of a hepatic fibrosis that was inducible by carbon tetrachloride (CCl4). Groups of Wistar rats received intraperitoneal (IP) injections of CCl4 (0.45 ml/kg [0.72 g CCl4/kg]) over the course of for 4 weeks. Sub-sets of CCl4-treated rats were also treated concurrently with rebamipide at 60 or 100 mg/kg. At 24 h after the final treatments, liver function and oxidative stress were indirectly assessed. The extent of hepatic fibrosis was evaluated using two fibrotic markers, hyaluronic acid (HA) and pro-collagen-III (Procol-III); isolated liver tissues underwent histology and were evaluated for interleukin (IL)-10 and PGE2 content. The results indicated that treatment with rebamipide significantly inhibited CCl4-induced increases in serum ALT and AST and also reduced oxidative stress induced by CCl4. Fibrotic marker assays revealed that either dose of rebamipide decreased the host levels of Procol-III and HA that had become elevated due to the CCl4. At the higher dose tested, rebamipide appeared to be able to permit the hosts to have a normal liver histology and to minimize any CCl4-induced collagen precipitation in the liver. Lastly, the use of rebamipide was seen to be associated with significant increases in liver levels of both PGE2 and the anti-inflammatory cytokine IL-10. Based on these findings, it is concluded that rebamipide can retard hepatic fibrosis induced by CCl4 and that this effect may, in part, be mediated by an induction of PGE2 and IL-10 in the liver itself.

Rebamipide suppresses TNF-α mediated inflammation in vitro and attenuates the severity of dermatitis in mice

Rebamipide is a routine drug for the treatment of gastritis in a clinical setting. Recently, it has been shown to protect against various inflammatory diseases, and has provided a potential therapy for these diseases. However, whether rebamipide has a role in dermatitis remains to be elucidated. Here, we found that rebamipide alleviated the inflammatory reaction induced by tumor necrosis factor-α in RAW264.7, a stable macrophage cell line. Furthermore, rebamipide treatment repressed activation of nuclear factor-kappaB signaling, a well-established inflammatory signaling pathway. Moreover, an oxazolone-induced dermatitis mouse model was established to investigate the role of rebamipide in vivo. PBS control group exhibited typical skin inflammation, whereas treatment with rebamipide remarkably attenuated a dermatitis phenotype in this mouse model. The protective role of rebamipide in dermatitis in vivo was probably due to its inhibition of nuclear factor-kappaB signaling. Collectively, rebamipide may represent a promising molecular target for the prevention and treatment of inflammatory skin diseases.

Inhibition by rebamipide of cytokine-induced or lipopolysaccharide-induced chemokine synthesis in human corneal fibroblasts

BACKGROUND/AIMS

The dry-eye drug rebamipide has mucin secretagogue activity in and anti-inflammatory effects on corneal epithelial cells. Corneal stromal fibroblasts (transdifferentiated keratocytes) function as immune modulators in the pathogenesis of chronic ocular allergic inflammation and in innate immune responses at the ocular surface. The possible anti-inflammatory effects of rebamipide on human corneal stromal fibroblasts were examined.

METHODS

Serum-deprived cells were incubated for 1 h with rebamipide and then for various times in the additional absence or presence of cytokines or bacterial lipopolysaccharide (LPS). The release of chemokines into culture supernatants was determined with ELISAs. The intracellular abundance of chemokine mRNAs was quantitated by reverse transcription and real-time PCR analysis. Degradation of the nuclear factor κB (NFκB) inhibitor IκBα was detected by immunoblot analysis.

RESULTS

Rebamipide suppressed the release of interleukin (IL)-8 and the upregulation of IL-8 mRNA induced by tumour necrosis factor α (TNF-α) or LPS in corneal fibroblasts. It also inhibited eotaxin-1 (CCL-11) expression at the protein and mRNA levels induced by the combination of TNF-α and IL-4. In addition, rebamipide attenuated the degradation of IκBα induced by TNF-α or LPS.

CONCLUSIONS

Rebamipide inhibited the synthesis of chemokines by corneal fibroblasts in association with suppression of NFκB signalling. Rebamipide may therefore prove effective for the treatment of corneal stromal inflammation associated with allergy or bacterial infection.

Rebamipide increases barrier function and attenuates TNFα-induced barrier disruption and cytokine expression in human corneal epithelial cells

BACKGROUND

Disruption of corneal epithelial barrier function by inflammation may contribute to the development of dry eye. The effects of rebamipide, a drug used for the treatment of dry eye, on barrier function and cytokine expression in a human corneal epithelial (HCE) cell line were examined.

METHODS

Barrier function of HCE cells was evaluated by measurement of transepithelial electrical resistance (TER). The subcellular localisation of the tight junction protein zonula occludens (ZO)-1 was examined by immunofluorescence analysis. The release of cytokines was determined with ELISAs, and the intracellular abundance of cytokine mRNAs was quantitated by reverse transcription and real-time PCR analysis. Degradation of the nuclear factor-κB inhibitor IκBα was detected by immunoblot analysis.

RESULTS

Rebamipide increased TER of HCE cells in a concentration-dependent manner as well as attenuating the loss of TER and the disappearance of ZO-1 from the cell surface induced by tumour necrosis factor α (TNFα). Rebamipide also suppressed TNFα-induced expression of interleukin-6 and interleukin-8 at the mRNA and protein levels and inhibited the TNFα-induced degradation of IκBα.

CONCLUSIONS

The upregulation of barrier function and the anti-inflammatory effects of rebamipide, together with its mucin secretagogue activity, may contribute to the effectiveness of this drug for the treatment of dry eye.