Acute respiratory distress syndrome (ARDS) is a fatal clinical condition that can be caused by pulmonary and non-pulmonary diseases. Oxidative stress and inflammation play key roles in the development of ARDS. In this study, we investigated whether ferulic acid (FA), an anti-oxidant, was beneficial for prophylaxis of ARDS. We established an ARDS rat model using lipopolysaccharide (LPS) administration. Lung injury was assessed by lung wet/dry ratio and broncho-alveolar lavage fluid (BALF) analysis. Hematoxylin and eosin staining was performed to evaluate the histological changes of the lungs. Enzyme-linked immunosorbent assay (ELISA) and immunoblotting were performed to detect proteins in BALF and lung tissue, respectively. Pulmonary function was determined by testing the oxygen level in BALF. FA pretreatment significantly alleviated LPS-induced pulmonary histological changes. FA reversed LPS-induced changes of lung wet/dry ratio, total protein in BALF, P(A-a)O2, and PaO2/FiO2. In addition, LPS dramatically up-regulated the secretion of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and IL-10 in BALF (P < 0.01). However, pretreatment of FA significantly improved LPS-induced inflammation. We found that FA indeed reduced oxidative stress in the lungs by testing malondialdehyde level, myeloperoxidase level, and total anti-oxidant capacity. We also proved that FA inactivated multiple mitogen-activated protein kinase signaling pathways in the lungs. In conclusion, FA alleviated LPS-induced ARDS through its anti-inflammatory and anti-oxidant activities.
Quercetin is a plant flavonoid and has antioxidative properties. In this study, we evaluated the therapeutic effect of quercetin on thyroid dysfunction in L‐thyroxin (LT4)‐induced hyperthyroidism rats. LT4 was used to prepare the experimental hyperthyroidism model via the intraperitoneal injection. Quercetin was injected at a series doses (5, 50, and 100 mg/kg) to LT4‐induced hypothyroidism rats once a day for 14 days. The body weight and food intake were measured once a week. The levels of thyroid hormones, liver function, oxidative stress markers, and antioxidant markers were measured using commercial enzyme‐linked immunosorbent assay kits. Hematoxylin–eosin staining was used to observe the thyroid tissue histological changes. The levels of nuclear and total nuclear factor erythroid 2‐related factor 2 (Nrf2) were determined by western blot. The liver oxidative stress markers in LT4‐induced hyperthyroidism Nrf2 knockout rats were determined to evaluate the role of Nrf2 on quercetin induced protective effects. LT4 administration increased the levels of serum triiodothyronine and thyroxine, activity of oxidative stress markers with a parallel decrease in antioxidant markers and Nrf2. However, the simultaneous administration of quercetin, reversed all these effects indicating its potential in the regulation of hyperthyroidism. Furthermore, the loss function of Nrf2 diminished these effects resulting from the quercetin application, indicating the inhibitory effects caused by the quercetin may be involved in Nrf2 signaling pathway. These results indicate that quercetin could be used to protect against experimental hyperthyroidism‐induced liver damage via Nrf2 signaling pathway.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.