Effect of Rhubarb on Heat Shock Protein 70 Expression in Lung Tissues from Rats with Acute Lung Injury Induced by Lipopolysaccharide

Abstract

We investigated the expression of HSP70 in acute lung injury (ALI) induced by endotoxin (lipopolysaccharide: LPS) and the protective mechanisms of rhubarb against ALI. LPS was injected into rats via the internal jugular vein to induce ALI and rhubarb extract was given by intraperitoneal injection. The rats were divided into 4 groups: saline control group; LPS-induced ALI group; ALI treated with prophylactic rhubarb group; and ALI treated with therapeutic rhubarb group. The rats were sacrificed 2 hours after injection of LPS or saline. Physiological and pathological examinations were conducted, including arterial gas analysis, lung coefficient, hematoxylin-eosin staining, and HSP70 expression (immunohistochemistry and Western blotting). In the LPS-induced ALI group, interstitial edema, neutrophil infiltration, plasma exudation in alveoli, and damaged vascular endothelium were observed. HSP70 levels were slightly increased in LPS-treated rats, while HSP70 expression was enhanced significantly and overall lung function was improved in rhubarb-treated groups compared to ALI model rats. These data confirm that rhubarb protects rats from LPS-induced ALI and upergulates HSP70 expression. Thus, the protective effect of rhubarb may be mediated by the HSP70 signaling pathway.