Protective effect of taurine on sepsis-induced lung injury via inhibiting the p38/MAPK signaling pathway

Sepsis, a leading cause of acute lung injury (ALI), is characterized by an overwhelming systemic inflammatory response and widespread organ injury, particularly in the lungs. Taurine, an intracellular free amino acid, has been used for the treatment of various diseases, including lung injury; however, the underlying mechanisms are unclear. The present study aimed to investigate the protective effect of taurine on septic ALI and the underlying mechanism. A septic ALI model was established by performing cecal ligation and puncture (CLP) surgery on Sprague Dawley rats. Following successful model establishment, rats were treated with taurine. The results of hematoxylin and eosin, respiratory function detection, malondialdehyde level and superoxide dismutase activity determination and ELSIA demonstrated that taurine significantly alleviated lung injury, restored respiratory function, reduced oxidation and decreased the concentrations of inflammatory factors in CLP-induced septic ALI model rats. In addition, compared with that in the ALI group, western blotting results indicated that taurine ameliorated lung epithelial injury by significantly increasing the expression levels of lung epithelial markers, E-cadherin and occludin. The western blotting results demonstrated that, compared with the control group, the p38/MAPK and NF-κB signaling pathways were significantly activated in CLP-induced septic ALI model rats, but taurine significantly suppressed ALI-mediated signaling pathway activation. To investigate the mechanism underlying taurine in the treatment of septic ALI, CLP-induced septic ALI model rats were treated with an antagonist of the p38/MAPK signaling pathway (SB203580). The effects of SB203580 on CLP-induced septic ALI model rats were similar to those of taurine. SB203580 significantly attenuated sepsis-induced lung injury and increases in IL-1β and TNF-α concentrations in the lung tissue. In addition, SB203580 promoted restoration of the injured lung tissue and respiratory function in CLP-induced septic ALI model rats. The western blotting results indicated that SB203580 significantly decreased the ratios of phosphorylated (p)-p38/p38 and p-p65/065, and increased the protein expression levels of E-cadherin and occludin compared with those in the ALI group. In summary, the present study demonstrated that taurine alleviated sepsis-induced lung injury, which was associated with suppression of the inflammatory response and oxidative stress via inhibiting the p38/MAPK signaling pathway. Therefore, the p38/MAPK signaling pathway may serve as a potential therapeutic target for the treatment of sepsis-induced ALI.