Preventive effects of curcumin on different aspiration material-induced lung injury in rats

We have studied whether curcumin protects different pulmonary aspiration material-induced lung injury in rats. The experiments were designed in 60 Sprague-Dawley rats, randomly allotted into one of six groups (n = 10): normal saline (NS, control), enteral formula (Biosorb Energy Plus, BIO), hydrochloric acid (HCl), NS + curcumin-treated, BIO + curcumin-treated, and HCl + curcumin-treated. NS, BIO, HCl were injected in to the lungs. The rats received curcumin twice daily only for 7 days. Seven days later, both lungs in all groups were examined histopathologically, immunohistochemically, and biochemically. Histopathologic examination was performed according to the presence of peribronchial inflammatory cell infiltration, alveolar septal infiltration, alveolar edema, alveolar exudate, alveolar histiocytes, interstitial fibrosis, granuloma, and necrosis formation. Immunohistochemical assessments were examined for the activity of inducible nitric oxide synthase (iNOS) and the expression of surfactant protein D (SP-D). Malondialdehyde (MDA), hydroxyproline (HP), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activity were measured in the lung tissue. Our findings show that curcumin inhibits the inflammatory response reducing significantly (P < 0.05) all histopathological parameters in different pulmonary aspiration models. Pulmonary aspiration significantly increased the tissue HP content, MDA levels and decreased the antioxidant enzyme (SOD, GSH-Px) activities. Curcumin treatment significantly decreased the elevated tissue HP content, and MDA levels and prevented inhibition of SOD, and GSH-Px enzymes in the tissues. Furthermore, our data suggest that there is a significant reduction in the activity of iNOS and a rise in the expression of SP-D in lung tissue of different pulmonary aspiration models with curcumin therapy. Our findings support the use of curcumin as a potential therapeutic agent in acute lung injury.