Abstract
Inhalation of crystalline silica causes silicosis, a type of occupational pulmonary fibrosis, is most prevalent among people working in industries related to construction.Curcumin being an antioxidant and anti-inflammatory in nature has shown anti-asthmatic effectsbut it has not yet been investigated to have any impact on silicosis. Therefore,our aim was to study impact of intranasal curcumin on lung fibrosis after sequentialsilica exposure. The mice model of silicosis was developed by intranasal silica instillation(2.5 mg/mice) for every alternate dayfor different durations, mainly 7, 14 and 21 days. This model of silicosis mimic chronic occupational exposure of silica dustand severe features of silicosis were developed in 21 days of silica exposure.One hour prior to silica administration, curcumin (5 mg/kg,i.n) and /or dexamethasone, a known corticosteroid (10 mg/kg,i.p)was administered in mice.Results haveshown that apart from being anti-inflammatory, curcumin is being reported here for the first time to possess anti-fibrotic effects where silica exposed airway inflammation and fibrosis was reduced after intranasal curcumin treatment. Reduced inflammatory cell recruitment, collagen deposition around the bronchioles and the alveolar spaces, hydroxyproline level and matrix metalloproteinases 9 (MMP 9) activity was noted in silicosis affected mice after curcumin administration.Remarkable reduction in oxidative stress markers like reactive oxygen species (ROS), nitric oxide, myeloperoxidases (MPO) and eosinophil peroxidase (EPO) levels wereobserved in curcumin treatment groupswhich was better and/or comparable to corticosteroid, dexamethasone.