Diammonium glycyrrhizinate lipid ligand ameliorates lipopolysaccharide-induced acute lung injury by modulating vascular endothelial barrier function

Abstract

Background: The present study investigated the attenuating effect of diammonium glycyrrhizinate lipid ligand (DGLL) on acute lung injury (ALI) and pulmonary edema induced by lipopolysaccharide (LPS) in rats.Methods: Rat ALI model was established by LPS (10 mg/kg) intraperitoneal injection, and DGLL (30, 60, 120 mg/kg) was administrated orall 1 hour before LPS infusion. Six hours after LPS stimulation, lung injury was evaluated by histological staining. Pulmonary edema was evaluated by lung wet-dry weight ratio, the protein concentration of bronchoalveolar lavage fluid (BALF), and the evans blue (EB) extravasation in lung tissues. The expression of cytokines and adhesion molecules in lung tissues were detected by ELISA method. The myeloperoxidase (MPO) expression was detected by immunohistochemical staining. Western blot was used to detect the expression changes of the proteins associated with pulmonary inflammation and microvascular permeability.Results: DGLL significantly inhibited LPS induced ALI, manifested as attenuation of MPO positive cells and TNF-α, IL-6, ICAM-1 expression in rat lung tissue. In addition, DGLL abrogated LPS-induced pulmonary edema, decreased the protein concentration in BALF and EB extravasation. Meanwhile, DGLL inhibited the degradation of vascular endothelial cadherin (VE-Cadherin) and tight junction protein, including ZO-1, Occludin, and JAM-1.Conclusions: DGLL has an inhibitory effect on LPS-induced rat ALI, which is related to the inhibition of inflammatory cell infiltration and microvascular barrier disruption. These results provide a theoretical basis for DGLL in the potential clinical treatment of ALI.