therapeutic effect of gallic acid against paraquat-induced lung injury in rat

Background: paraquat (pq), a potent herbicide, is extremely toxic to humans when exposed orally and it is known to induce lung injury via a redox cyclic reaction. objectives: the current study aimed at examining the effect of gallic acid (ga), a polyphenolic compound, which is a constituent of plant-derived foods, against pq-induced lung injury and pulmonary fibrosis in association with its antioxidant activity. methods: male rats were randomly divided into 5 experimental groups each containing 14 rats. group 1 received normal saline for 21 days. group 2 received a single dose of oral administration of pq (50 mg/kg, only on first day) for 21 days. groups 3 to 5 were treated with different doses of ga after pq ingestion for 21 days. seven animals from each group were sacrificed on the days 7 and 21. results: the results showed that paraquat gavage, significantly enhanced the inflammatory and fibrotic modifications, hydroxyproline (hp), levels of malondialdehyde (mda), main proinflammatory cytokines such as tumor necrosis factor-α (tnf-α), interleukin-6 (il-6), and transforming growth factor (tgf)-β1 as a pro-fibrotic mediator in lung tissue. it also, significantly diminished enzymatic antioxidant amounts such as catalase (cat), superoxide dismutase (sod), and glutathione peroxidase (gpx) activity and non-enzymatic amounts such as glutathione (gsh) content in the rat lung tissue. however, after ga treatment all of these biochemical indices were diminished with a dose dependent manner and histopathological alterations were also close to normal status. conclusions: the current study indicated that the ga improved the pq-induced lung injury and prevented the process of pulmonary fibrosis via its antioxidant and immunomodulatory properties.