Ischemic Postconditioning Mitigates Lipopolysaccharide-induced Acute Lung Injury in Rats

Acute lung injury (ALI) is a syndrome characterized by the disruption of alveolar endothelial and epithelial barriers, neutrophilic infiltration in pulmonary regions, and non-cardiogenic edema, associated with high mortality and morbidity. Despite intensive research efforts, there is currently no approved specific treatment for the condition. The aim of this study was to investigate the potential beneficial effect of ischemic post-conditioning in lipopolysaccharide (LPS)-induced lung injury and its possible association with inflammatory and apoptotic processes.

Lung injury was induced in rats by a single intraperitoneal administration of 10 mg/kg LPS. Under anesthesia, latex tourniquets were wrapped around both hind limbs of the animals in a region close to the body to achieve complete ischemia. The ischemic conditioning procedure consisted of four cycles of 10 min of ischemia followed by 10 min of reperfusion. Inflammation, and apoptosis levels were measured using ELISA. Hematoxylin and eosin staining was used for histopathological evaluation, while TUNEL staining was employed for apoptotic cell counting. One-way analysis of variance (ANOVA) with post hoc Tukey test was used for comparisons between groups.

Intraperitoneal LPS administration induced neutrophil infiltration and apoptotic cell death in lung tissue. These effects were prevented by remote ischemic postconditioning (RIPostC) application. Additionally, the beneficial effects of ischemic conditioning can be transferred via serum.

RIPostC can ameliorate LPS-induced ALI. The mechanism of the protective effects of RIPostC may lie in the suppression of apoptosis and neutrophil infiltration.