Abstract:The ameliorative effects of Cordyceps militaris extracts against PM2.5 induced lung injury in mice were studied.PM2.5 was administered to mice via intratracheal instillation.Bronchoalveolar lavage fluid（BALF）was collected for counting inflammatory cells.The activities of acid phosphatase（ACP），alkaline phosphatase（AKP）and lactate dehydrogenase （LDH）in BALF were measured. Enzyme-linked immunoabsorbent assay（ELISA）commercial available kits were employed to determine the levels of serum immunoglobulin IgA，IgG，IgM，tumor necrosis factor α（TNF-α），interleukin（IL）-2. Furthermore，the activities of total antioxidant capacity（T-AOC），superoxide dismutase（SOD），catalase（CAT），glutathione peroxidase（GSH-PX），and the contents of malondialdehyde （MDA）in the lung tissue were determined. The results revealed that PM2.5 treatment caused an increase in the number of inflammatory cells in lavage fluid，while Cordyceps militaris extracts inhibited this change. The increased activities of ACP，AKP，and LDH in BALF after PM2.5 treatment was also inhibited by Cordyceps militaris extracts.In addition，Cordyceps militaris extracts not only remarkably promoted the expression of IL-6，TNF-α，IgA，IgM，and IgG，but also effectively increased the T-AOC，SOD，CAT，GSH-Px activities，and inhibited the increase in MDA level.These results indicate that Cordycepsmilitaris extracts might be of therapeutic value in ameliorating the inflammatory injury and oxidative stress caused by PM2.5，via its anti-inflammatory and antioxidant potential.