Protective Effect of Antagonist of High-mobility Group Box 1 on Lipopolysaccharide-Induced Acute Lung Injury in Mice

We explored the effects of recombinant A-box (rA-box), a specific blockade for endogenous high mobility group box 1 (HMGB1) protein, on acute lung inflammation induced by lipopolysaccharide (LPS) in vivo. Acute lung injury (ALI) was produced successfully by intratracheal administration of LPS (10 mu g/mouse) in male BALB/c mice. rA-box (0.3, 0.6 mg/mouse, i.p.) was administered 30 min prior to or 2 h after LPS exposure. Bronchoalveolar lavage fluid (BALF) was obtained to measure chemokines, proinflammatory cytokines, total cell counts and proteins at the indicated time points. It was found that rA-box caused a significant reduction in the total cells and neutrophils in BALF, a significant reduction in the W/D ratio and protein leakage at 24 h after LPS challenge. In addition, rA-box was also believed to have downregulated the expression of LPS-induced chemokines (keratinocyte-derived chemokine) and proinflammatory cytokines, including early mediator TNF-a and late mediator HMGB1. These findings confirm the significant protection of rA-box against LPS-induced ALI, and the effect mechanism of rA-box was associated with decreasing the expression of chemokines and proinflammatory cytokines.