Curcumin protects against sepsis-induced acute lung injury in rats

The present study aimed to investigate the effect of curcumin on sepsis-induced acute lung injury (ALI) in rats, and explore its possible mechanisms. Male Sprague-Dawley rats were randomly divided into the following five experimental groups (n = 20 per group): animals undergoing a sham cecal ligature puncture (CLP) (sham group); animals undergoing CLP (control group); or animals undergoing CLP and treated with vehicle (vehicle group), curcumin at 50 mg/kg (low-dose curcumin [L-Cur] group), or curcumin at 200 mg/kg (high-dose curcumin [H-Cur] group).At 6, 12, 24 h after CLP, blood, bronchoalveolar lavage fluid (BALF) and lung tissue were collected. The lung wet/dry weight (W/D) ratio, protein level, and the number of inflammatory cells in the BALF were determined. Optical microscopy was performed to examine the pathologic changes in lungs. Myeloperoxidase (MPO) activity, malondialdehyde (MDA) content, as well as superoxidase dismutase (SOD) activity were measured in lung tissues. The expression of inflammatory cytokines, tumor necrosis factor-alpha (TNF-α), interluekin-8 (IL-8), and macrophage migration inhibitory factor (MIF) were determined in the BALF. Survival rates were recorded at 72 h in the five groups in another experiment. Treatment with curcumin significantly attenuated the CLP-induced pulmonary edema and inflammation, as it significantly decreased lung W/D ratio, protein concentration, and the accumulation of the inflammatory cells in the BALF, as well as pulmonary MPO activity. This was supported by the histopathologic examination, which revealed marked attenuation of CLP-induced ALI in curcumin treated rats. In addition, curcumin significantly increased SOD activity with significant decrease in MDA content in the lung. Also, curcumin caused down-regulation of the inflammatory cytokines TNF-α, IL-8, and MIF levels in the lung. Importantly, curcumin improved the survival rate of rats by 40%-50% with CLP-induced ALI. Taken together, these results demonstrate the protective effects of curcumin against the CLP-induced ALI. This effect can be attributed to curcumin ability to counteract the inflammatory cells infiltration and, hence, ROS generation and regulate cytokine effects.