The effect of quercetin, a flavonoid, on lung injury caused by sepsis

Background/Aim: Lung injury is frequently observed in cases with sepsis, which can lead to conditions that progress to acute respiratory distress syndrome (ARDS) causing mortality. There is no specific treatment for sepsis or sepsis-induced lung injury. Antioxidant therapy has been one of the most prominent options for treatment, according to pathophysiological studies. The aim of this study was to investigate the effects of quercetin, a powerful antioxidant, on sepsis and sepsis-related lung injury. Methods: Thirty-two adult male Sprague Dawley rats were divided into five groups. The control group (CNRL) received 1.5 ml saline via the intragastric route. The quercetin group (QUER [n=5]) underwent no sepsis procedure and received 20 mg/kg quercetin via the intragastric route starting 15 days before the procedure. The sham group (SHAM [n=6]) underwent a surgical incision and received 1.5 ml intragastric olive oil (quercetin dissolves in oil). The sepsis group (SEPS [n=7]) underwent the sepsis procedure. The sepsis and quercetin group (SEPS+QUER [n=7]) underwent the sepsis procedure and received 20 mg/kg quercetin via the intragastric route for 15 days before the procedure. Cecal ligation and puncture methods were used to induce sepsis. While ALT, AST, LDH, GGT and CRP values were analyzed from rat blood, MDA and GSH levels were analyzed from lung tissue. Results: The results showed that quercetin reduced neutrophil infiltration (TLIS 3.5 [0.26] in the SEPS group vs TLIS 2.75 [0.29] in the SEPS+QUER group [P=0.01]), intra-alveolar macrophage count (SEPS vs SEPS+QUER [P=0.01]) and cell proliferation (SEPS vs SEPS+QUER [P=0.01]), and that it helped to preserve lung anatomy during sepsis. It was observed that MDA levels in the lung tissue decreased with the treatment of quercetin to septic rats (SEPS vs SEPS+QUER [P=0.046]). Conclusion: These findings suggest that quercetin may be a potential treatment option for sepsis. However, more studies are needed to determine whether quercetin is a viable option as a therapeutic strategy in patients.