Ketamine effect on HMGB1 and TLR4 expression in rats with acute lung injury.

Acute lung injury (ALI) is a common emergency and severe case in clinic. High mobility group protein box 1 (HMGB1) can be treated as a new anti-inflammatory treatment target. Toll-like receptor 4 (TLR4) is an important receptor of HMGB1. Ketamine is a widely used intravenous anesthetic with good anti-inflammatory and immune regulating function. Whether it can protect ALI through inhibiting HMGB1 and TLR4 expression in lung tissue still needs further investigation. Male SD rats were randomly divided into control, lipopolysaccharide (LPS) group and ketamine intervention group with 15 rats in each group. The rats were euthanatized at 24 h after modeling and the bronchoalveolar lavage fluid (BALF) was collected for HMGB1 and TLR4 level detection. Western Blot was applied to analyze HMGB1 and TLR4 protein expression in the lung tissue. HMGB1 and TLR4 concentration in BALF were 5.369 ± 1.564 ng/ml and 43.980 ± 7.524 pg/ml in the control, respectively. They were 12.358 ± 4.681 ng/ml and 102.538 ± 8.412 pg/ml in LPS group, and 7.399 ± 2.346 ng/ml and 87.208 ± 7.558 pg/ml in ketamine intervention group, respectively. Their levels increased significantly in LPS group and down-regulated after ketamine intervention. HMGB1 and TLR4 protein expression in lung tissue elevated obviously in LPS group, and decreased after ketamine treatment. HMGB1 and TLR4 protein level showed positive correlation in lung tissue (r = 0.921, P < 0.001). Ketamine can inhibit HMGB1 and TLR4 expression in ALI, and alleviate LPS induced rat lung injury.

Severity of sepsis is correlated with the elevation of serum high-mobility group box 1 in rats.

BACKGROUND: Sepsis is a leading cause of death in the intensive care units. The late inflammatory cytokine, high-mobility group box 1 (HMGB1), plays a critical role in sepsis. In the present study, we investigated the association between the serum HMGB1 levels and the severity of organ injury in the lipopolysaccharide-induced sepsis in rats. METHODS: To produce an animal model of sepsis with different degree of organ injury, animals were treated with three different doses of lipopolysaccharide (4, 8 and 16 mg/kg), and the animals in control group were treated with the same volume of the vehicle (saline). The levels of serum HMGB1 were measured at 0, 2, 4, 8, 16, 24, 32 and 48 hours after lipopolysaccharide (LPS) or vehicle injection, meanwhile the biochemical and histopathological indicators for the severity of organ injury were assessed. RESULTS: The level of HMGB1 had a positive, high correlation with the abnormal changes of serum cardiac troponin I, alanine aminotransferase, aspartate aminotransferase, creatinine and blood urea nitrogen, as well as the pathologic scores of heart, lung, liver and kidney. CONCLUSIONS: The level of serum HMGB1 is highly correlated with the severity of sepsis in rats, suggesting that HMGB1 could serve as a valuable adjunct in the diagnosis and management of sepsis.