Chlorogenic acid protective effects on paraquat-induced pulmonary oxidative damage and fibrosis in rats

Paraquat (PQ) is a widely used herbicide that can cause severe oxidative and fibrotic injuries in lung tissue. Due to the antioxidant and anti-inflammatory properties of chlorogenic acid (CGA), the present study investigated its effects on PQ-induced pulmonary toxicity. To this end, 30 male rats were randomly categorized into five groups of six. Initially, the first and third groups were treated intraperitoneally (IP) with normal saline and CGA (80 mg/kg) for 28 consecutive days, respectively. The second, fourth, and fifth groups were treated with normal saline and 20 and 80 mg/kg of CGA for 28 consecutive days, respectively, and received a single dose of PQ (IP, 20 mg/kg) on Day 7. Then, the animals were anesthetized with ketamine and xylazine, and lung tissue samples were collected for biochemical and histological examinations. The results showed that PQ significantly increased hydroxyproline (HP) and lipid peroxidation (LPO) and decreased the lung tissue antioxidant capacity. In addition, myeloperoxidase (MPO) activity increased significantly, while glutathione peroxidase (GPx), catalase (CAT), and superoxide dismutase (SOD) activity declined substantially. The administration of therapeutic doses of CGA could prevent the oxidative, fibrotic, and inflammatory effects of PQ-induced lung toxicity, and these changes were consistent with histological observations. In conclusion, CGA may improve the antioxidant defense of lung tissue and prevent the spread of inflammation and the development of PQ-induced fibrotic injuries by enhancing antioxidant enzymes and preventing inflammatory cell infiltration.