Resveratrol prevents nanoparticles-induced inflammation and oxidative stress via downregulation of PKC-α and NADPH oxidase in lung epithelial A549 cells

Background: Exposure to carbon black nanoparticles (CBNPs), a well-known industrial production, promotes pulmonary toxicity through inflammation and oxidative stress. Recent studies show that some polyphenols exert their antioxidant properties through regulation of protein kinase C-alpha (PKC-alpha) and NADPH oxidase (Nox) signaling. Resveratrol, a dietary polyphenol in fruits, possesses various health beneficial effects including anti-inflammatory and antioxidative properties. In this study, we aimed to elucidate the involvement of PKC-alpha and Nox in CBNPs-induced inflammation and oxidative stress, and to investigate the protective effects of resveratrol on CBNP-induced inflammation and oxidative stress in human lung epithelial A549 cells. Methods: The production of reactive oxygen species (ROS) and the change of mitochondrial membrane potential (Delta psi m) were measured by flow cytometry. Nitric oxide (NO) was measured using the Griess reagent, and prostaglandin E-2 (PGE(2)) production was detected by ELISA, while protein expressions were measured by Western blotting analysis. Results: In lung epithelial A549 cells, CBNPs significantly enhanced oxidative stress by upregulation of Nox2 and membrane expression of p67(phox) accompanied with increase of ROS production. CBNPs also increased inflammatory factors, including iNOS, COX-2, NO and PGE(2). However, resveratrol attenuated the above effects induced by CBNPs in A549 cells; additionally, CBNPs-induced activation of PKC-alpha was observed. We found that PKC-alpha inhibitor (Go6976) could attenuate CBNPs-induced inflammation by down-regulation of ROS, NO and PGE(2) production in A549 cells, suggesting PKC-alpha might be involved in CBNPs-induced oxidative stress and inflammation. Our results also found resveratrol was able to inhibit protein expression of PKC-alpha induced by CBNPs. Moreover, ROS scavenger (NAC) and Nox inhibitor (DPI) attenuated CBNPs-induced expressions of iNOS and COX-2. DPI could also attenuate CBNPs-induced ROS, NO and PGE(2) production. Conclusions: Resveratrol attenuated CBNPs-induced oxidative and inflammatory factors in lung epithelial A549 cells, at least in part via inhibiting PKC-alpha- and Nox-related signaling.