Seeds of Ginkgo biloba L. inhibit oxidative stress and inflammation induced by cigarette smoke in COPD rats through the Nrf2 pathway

Ethnopharmacological relevance: As a traditional medicine, seeds of Ginkgo biloba L. (Gbs) have been used to treat cough or asthma for a long time. It is commonly used in clinic for lung diseases. However, its mechanism of lung protection is not completely clear. Aims of the study: This research was designed to explore the protective effects of Gbs on antioxidant and inflammation during the chronic obstructive pulmonary disease (COPD) pathological process provoked by cigarette smoking (CS) in rats. Materials and methods: Six random groups including control group, CS model group, Gbs intervention groups (25 mg/kg, 50 mg/kg, and 100 mg/kg) and aminophylline group were composed of forty-eight rats. Smoking and intratracheal instillation of lipopolysaccharide (LPS) were used to establish the COPD rat model. Glutathione peroxidase (GSH-PX), malondialdehyde (MDA), superoxide dismutase (SOD), and enzyme-linked immunosorbent assay (ELISA) was used for quantifying the inflammatory factors such as IL-8, IL-6, IL-10, IL-17 and TNF-alpha. Western blotting were used for detecting the protein expressions of Nrf2, Keap1 and HO-1 in the lung tissues. Results: Gbs inhibits lung histological changes and decreased the inflammatory factors in both bronchoalveolar lavage fluid (BALE) and serum of CS-exposed rats, including IL-10, IL-17, IL-6, IL-8 and TNF-alpha. Gbs also inhibited the MDA level, increased SOD and GSH-PX activity in serum and changed expressions of Nrf2, Keapl and HO-1 in the lung tissues. Conclusion: Gbs inhibit oxidative stress and inflammation induced by cigarette smoke in COPD rats through the Nrf2 Pathway.