J Rheum Dis.  2012 Aug;19(4):206-211. 10.4078/jrd.2012.19.4.206.

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

• Jun JB
• Kim JK
• Na YI
• Han H
• Paik SS
• Kim SH
• Kim YH

• KMID: 2223072
• DOI: http://doi.org/10.4078/jrd.2012.19.4.206

Abstract

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.

Keyword

Scleroderma; Flavonoid; Apigenin; Bleomycin; Methylcellulose gel

MeSH Terms

Animals
Apigenin
Bleomycin
Collagen
Connective Tissue Diseases
Connective Tissue Growth Factor
Contracts
Extracellular Matrix
Fibrosis
Gels
Injections, Subcutaneous
Lung
Methylcellulose
Mice
Models, Animal
Molecular Weight
Myofibroblasts
Phenotype
Scleroderma, Systemic
Skin
Apigenin
Bleomycin
Collagen
Connective Tissue Growth Factor
Gels
Methylcellulose

Figure

• 

  Figure 1 Histological examination of skin: (A) Dermal thickness (rectangular blank bar, µm) on hematoxylin and eosin stain (×200), (B) Semi-quantitative analysis of fibrosis on Masson-Trichrome stain (×200), and (C) Semi-quantitative analysis of mast cell infiltration on toluidine blue stain (arrow indicated) (×400). In the MC-BLM group, dermal thickness, fibrosis, and mast cell infiltration were increased, compared to the MC-PBS control group, but intraperitoneal injection of apigenin (1.0 mg/kg and 2.5 mg/kg) did not decrease these changes in intraperitoneal apigenin groups. MC: methylcellulose gel, PBS: phosphate buffered saline, BLM: bleomycin, AP: apigenin.

• 

  Figure 2 Histological examination of the lung. Histological grading of lung tissue on Masson-Trichrome stain (upper panel: ×40, lower panel: ×200). In the MC-BLM group, the lung histological grade was increased, compared to the MC-PBS control group, but intraperitoneal injection of apigenin (1.0 mg/kg and 2.5 mg/kg) did not decrease these changes in intraperitoneal apigenin groups. MC: methylcellulose gel, PBS: phosphate buffered saline, BLM: bleomycin, AP: apigenin.

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