Dietary Flavonoid Apigenin is not Effective in Preventing Development of a Bleomycin-Induced Murine Model of Scleroderma

OBJECTIVE: Systemic sclerosis is a connective tissue disease characterized by vasculopathy, excessive accumulation of extracellular matrix, and fibrosis of the skin and internal organs. The dietary flavonoid apigenin has been shown to reduce expression of the myofibroblast phenotype and to inhibit contraction of collagen gels. We investigated the effect of apigenin on the prevention and treatment of a modified bleomycin-induced animal model of scleroderma. METHODS: Recently, we successfully induced scleroderma by weekly subcutaneous injections of bleomycin using a thermo-reversible combination gel composed of low molecular weight methylcellulose. A weekly subcutaneous injection of methylcellulose gel loaded with bleomycin induced focal skin fibrosis on the back skin and fibrotic phenotype of lung tissue in mice. The histologic examination of skin and lungs, collagen assay of lungs, and expression of connective tissue growth factor were investigated. RESULTS: Daily intra-peritoneal injection of 1.0 mg/kg or 2.5 mg/kg of apigenin starting a week before the bleomycin injections failed to prevent the development of skin fibrosis and reduce the fibrotic phenotypes of skin and lung tissue. CONCLUSION: Although some in vitro experiments have supported a potential role of apigenin in the treatment of fibrosis, dietary flavonoid apigenin is not effective in preventing development of a bleomycin-induced murine model of scleroderma.

Inhibition of the IL-1beta-induced Expression of Matrix Metalloproteinases by Controlled Release of IL-1 Receptor Antagonist Using Injectable and Thermo-reversible Gels in Human Osteoarthritis Chondrocytes

OBJECTIVE: IL-1beta is involved in the degradation of articular cartilage in various arthritides, including osteoarthritis (OA). Competitive inhibition of IL-1beta by IL-1 receptor antagonists (IL-1Ra) may represent a pathogenesis-based strategy for inhibiting degradation of the cartilage matrix. We investigated the hypothesis that controlled release of IL-1Ra using injectable, thermoreversible and complex coacervate combination gels as drug delivery systems might reduce matrix degradation in OA. METHODS: Thermoreversible combination gels that can be injected into joints were formed in aqueous solution by making a complex coacervate with recombinant human IL-1Ra (anakinra) and cationic macromolecules, and this was followed by co-formulation with methylcellulose as a negative thermosensitive polysaccharide. Gels containing anakinra were positioned in the upper insert of a transwell system and human OA chondrocytes were placed in the lower compartment and then they were stimulated with IL-1beta. The expression of matrix metalloproteinases (MMPs) was examined by performing real time PCR and ELISA. RESULTS: Complex coacervation between anakinra and protamine was successfully completed. IL-1Ra was released from the gels in a sustained release pattern for extended periods with minimal initial bursts. IL-1beta markedly enhanced the expression of MMP. The IL-1Ra released from the gels significantly inhibited the IL-1beta-induced MMP expression in the chondrocytes. CONCLUSION: We developed and optimized a novel injectable and thermoreversible gel system for the controlled release of IL-1Ra, and this drug delivery system effectively inhibited the IL-1beta-induced MMP expression of chondrocytes in a transwell system. Intra-articular local delivery of injectable and thermoreversible gels containing IL-1Ra into knees has the potential to provide prolonged therapy based on the pathophysiology of knee OA.