Thearubigin regulates the production of Nrf2 and alleviates LPS-induced acute lung injury in neonatal rats

This study was undertaken to investigate the effect of natural bioactive compound thearubigin on neonatal acute lung injury (ALI) using LPS-induced ALI as a model. We also attempted to understand the possible underlying mechanism. The effect of thearubigin on lung wet-to-dry weight ratio, the activity of LDH, lung histopathology, BALF protein levels, the activity of MPO, production and extravasation of cytokines and oxidative stress were studied. The results showed that thearubigin caused a significant reduction in lung inflammation as evident from lung wet-to-dry weight ratio, BALF protein levels and MPO activity and histopathological analysis. It was further observed that the attenuation in inflammation happened due to a significant reduction in cytokine levels in alveolar cavities. Thearubigin also showed strong antioxidant properties as evidenced by reduced levels of oxygen species such as H2O2, MDA and OH ion. Additionally, the antioxidant response element nuclear factor erythroid-2-related factor 2 (Nrf2) pathway was found to be activated in thearubigin-treated group. These results provided a possible mechanism of antioxidant activity of thearubigin in neonatal ALI. Overall, this study showed that thearubigin can be a natural alternative for the treatment of neonatal ALI. However, further studies are required to understand its mechanism antioxidant and anti-inflammatory action.