Esketamine Reduces Lung Injury Caused by Limb Ischemia-Reperfusion by Regulating Oxidative Stress via the TLR4/NF-κB/NLRP3 Pathway.

Background: Esketamine has shown promise in mitigating tissue damage caused by ischemia- reperfusion injury, making it a potential therapeutic candidate for acute lung injury (ALI) induced by limb ischemia-reperfusion (LIR-ALI).

Objective: This study sought to explore the role and mechanism of esketamine in the LIR-ALI rat model.

Methods: The effects of esketamine on the LIR-ALI rats model were evaluated through histopathological examination, assessment of pulmonary edema, measurement of MDA and SOD levels, and analysis of inflammatory cytokine levels (IL-1β, etc.) in the bronchoalveolar fluid (BALF) and serum. Western blot analysis was used to assess the expressions of TLR4, NF-κB, and NLRP3. TLR4 agonist, LPS, was used to validate the role of NF-κB/NLRP3 pathway in LIRALI.

Results: Esketamine significantly alleviated LIR-induced ALI by reducing pulmonary edema, inflammatory cell infiltration, and oxidative stress. Elevated MDA content and suppressed SOD activity were significantly reversed by esketamine, along with inactivity of the TLR4/NF-κB/NLRP3 pathway. Esketamine treatment reduced inflammatory response in BALF and serum. TLR4 activation by LPS reversed the ameliorative effects of esketamine on LIR-ALI.

Conclusion: Esketamine protected against LIR-induced ALI by mitigating oxidative stress and suppressing the TLR4/NF-κB/NLRP3 axis. These findings highlight the potential therapeutic value of esketamine for ALI.