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Extracts of propolis, a natural beehive product, have been known for centuries to have a variety of beneficial medical properties, among which their anti-inflammatory effect is a major one. Caffeic acid phenethyl ester (CAPE), an active propolis component, has antimicrobial, anti-inflammatory, antioxidant, carcinostatic and immunomodulatory properties. In this study, we aimed to investigate the efficacy of CAPE in endotoxin-induced lung injury in rats. Lung injury was induced by a footpad injection of lipopolysaccharide (LPS). In the treatment group, 10 micromol kg(-1) CAPE was injected intraperitoneally immediately after LPS injection. At 24 h after LPS and/or CAPE injection, blood and lung tissue specimens were collected. MDA levels and MPO activity in serum and lung tissue, serum total antioxidant levels, lung tissue Na(+)/K(+) ATP-ase activity and histopathological evaluation were determined to assess the efficacy of CAPE treatment. CAPE was found to be efficient in reducing inflammation and lung tissue damage induced by LPS in rats.

Since oleic acid (OA) induces morphologic and cellular changes similar to those observed in human acute lung injury (ALI) and acute respiratory distress syndrome, it has become a widely used model to investigate the effects of several agents on pathogenesis of lung injury. The antioxidant and anti-inflammatory properties of N-acetylcysteine (NAC) has been documented in many lung injury models. In this study, we evaluated the role of NAC in an OA-induced lung injury model by measuring myeloperoxidase (MPO) activity, malondialdehyde (MDA) and 3-nitrotyrosine (3-NT) levels in lung tissue. Five groups labelled Sham, NAC, OA, Pre-OA-NAC and Post-OA-NAC were determined. ALI was induced by intravenous administration of OA. The pre-OA-NAC group received iv NAC 15 min before OA infusion and the post-OA-NAC group received iv NAC 2 h after OA infusion. In both of the NAC treatment groups' blood and tissue samples were collected 4 h after OA infusion, independent from the time of NAC infusion. The MPO activity, MDA and 3-NT levels in lung homogenates were found to be increased in OA group and the administration of NAC significantly reduced tissue MPO, MDA and 3-NT levels (p = 0.0001) Lung histopathology was also affected by NAC in this OA-induced experimental lung injury model.