The therapeutic effect of Apocynin against hyperoxy and Inflammation-Induced lung injury

Lung damage due to hyperoxia and inflammation are important causes of bronchopulmonary dysplasia (BPD). We aimed to investigate the beneficial effects of Apocynin (Apo) on rat pups exposed to hyperoxia and inflammation. Forty-eight rat pups were randomly divided into 3 groups as hyperoxia (95% O₂) + lipopolysaccharide (LPS), hyperoxia + LPS + Apo treated and control (21% O₂). Rat pups in the Apo group received Apo at a daily dose of 40 mg/kg. Histopathological (Hematoxylin-Eosin, Masson trichrome), immunochemical (surfactant B and C protein staining) evaluations and biochemical studies incluiding, total antioxidant status (TAS), total oxidant status (TOS), OSI (oxidant stress index), AOPP (advanced protein degradation product), Lipid hydroperoxide (LPO), 8-OHdG, NADPH oxidase activity (NOX), superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), myeloperoxidase (MPO), tumor necrosis factor-alpha (TNF- α), interleukin-1 beta (IL-1β), IL-18, IL-6, caspase-1 and 3, nuclear factor erythroid 2-related factor 2 (NFR2), Nod-like receptor pyrin domain-containing 3 (NLRP3) activities were studied. After Apo treatment, AOPP, LPO, 8-OHdG, NOX, TOS, OSI levels decreased; SOD, CAT, GSH and TAS levels increased (P < 0.05). Apo reduced inflammatory cell infiltration and proinflammatory cytokines with reduction in NLRP3 inflammasome in addition to increased Nrf2 levels. Moreover, caspase-1 and 3 levels decreased with Apo (P < 0.05). Apo was found to provide preventive and therapeutic effects by reducing oxidant stress, blocking inflammation and increasing antioxidant status. Beyond anti-oxidative effects, Apo also have anti-inflammatory effects by suppressing NLRP3 inflammasome activation and inducing Nrf2 as well. Therefore, Apo might be a potential option in the treatment of BPD.