Modulation of autophagy in the protective effect of resveratrol on PM2.5-induced pulmonary oxidative injury in mice.

Ambient fine particulate matter (PM2.5) is capable of inducing pulmonary oxidative injury. Autophagy maintains basal cellular homeostasis and plays a critical role in the pathogenesis of lung diseases. Resveratrol, a natural polyphenol, is an effective antioxidant agent against particulate matter (PM)-induced injuries. The current study was designed to investigate whether resveratrol can regulate autophagy in the process of PM2.5-mediated pulmonary oxidative injury. In the mice model of PM2.5 exposure, we found that PM2.5 increased the contents of malondialdehyde (MDA) and nitric oxide (NO) while decreased the expression of nuclear factor erythroid-2-related factor 2 in the lungs. The levels of 8-hydroxydeoxyguanosine and inflammatory cytokines were increased following PM2.5 exposure. Histological analysis of the lungs revealed inflammatory change in PM2.5 group. Meanwhile, PM2.5 triggered autophagy, as evidenced by the elevated expression of microtubule-associated proteins light chain 3II, Beclin1 and p62. Transmission electron microscopy images showed that autophagosomes accumulated in the lungs after PM2.5 exposure. Furthermore, resveratrol intervention suppressed autophagy and attenuated the oxidative injury resulting from PM2.5 exposure. Our findings provided a valuable insight into the underlying mechanism for the protective effects of resveratrol against PM2.5-induced lung injury, which involves suppression of the autophagic process.

Resveratrol relieves particulate matter (mean diameter < 2.5 µm)-induced oxidative injury of lung cells through attenuation of autophagy deregulation.

Oxidative stress and inflammation are critically implicated in ambient fine particulate matter (mean diameter < 2.5 µm; PM2.5 )-induced lung injury. Autophagy, playing a crucial role in various physiopathological conditions, modulates cellular homeostasis and stress adaptation. Resveratrol is a phytoalexin that exerts potent antioxidant effects on cardiopulmonary diseases. To date, the mechanisms by which resveratrol protects against PM2.5 remain to be elucidated. In the present study, we investigated the effect of resveratrol on PM2.5 -induced oxidative injury. The potential role of nuclear factor erythroid-2-related factor 2 and autophagy in this progress was explored. Human bronchial epithelial cells were treated with PM2.5 and the cytotoxicity and oxidative stress markers were determined. The results showed that PM2.5 decreased cell viability and elevated the level of lactate dehydrogenase. The levels of malondialdehyde and reactive oxygen species were increased by PM2.5 exposure. PM2.5 also induced a significant increase of the inflammatory cytokines including interleukin (IL)-6, IL-8, IL-1ß and tumor necrosis factor α. Meanwhile, PM2.5 triggered autophagy formation and alteration of the nuclear factor erythroid-2-related factor 2 pathway. Furthermore, human bronchial epithelial cells were co-treated with PM2.5 and resveratrol in the presence or absence of 3-methylamphetamine, an inhibitor of autophagic formation. It was revealed that resveratrol intervention abolished PM2.5 -induced oxidative injury partially through the suppression of autophagy deregulation. Findings from this study could provide new insights into the molecular mechanisms of pulmonary intervention during PM2.5 exposure.