Endotoxin-induced liver damage in rats is minimized by β2-adrenoceptor stimulation

Objective and Design: To investigate the effects of beta(2)-adrenoceptor (beta(2)-AR) stimulation on endotoxin-induced liver damage and systemic cytokine levels in rats. Subjects: Standard male Wistar rats. Treatment: A disease-model of lipolysaccharide (LPS)-induced acute systemic inflammation was used. The beta(2)-selective AR agonist clenbuterol was administered before, during, and after LPS-challenge to investigate its effects on the acute inflammatory response and associated liver-failure. Methods: The following parameters have been measured in plasma: TNFalpha, IL-1beta, IL-6, IL-10, AST, ALT, and Bilirubin. Liver histological examination was performed to look for changes in tissue morphology. Results: Administration of clenbuterol (p.o.) one hour before, or intravenous at the same time as LPS-challenge resulted in a marked reduction of plasma levels of TNFalpha, IL-1beta, and IL-6. A change both in plasma-level and in time-concentration profile of the anti-inflammatory cytokine IL-10 was found. Clenbuterol minimized LPS-induced liver damage, as represented by significantly lowered concentrations of several parameters for liver-failure (AST, ALT, Bilirubin), and improved hepatic tissue morphology. Clenbuterol administration after LPS challenge failed to inhibit TNFalpha-release but reduced liver-damage. Simultaneous use of the beta(2)-AR antagonist propranolol augmented LPS-induced liver failure, suggesting a role of endogenous adrenoceptor-agonists in prevention of organ-failure during systemic inflammation. Conclusions: The results indicate that a selective beta(2)-AR agonist might be used as an additional therapeutic agent in the clinic for the treatment of (acute) systemic inflammatory disorders in order to reduce or prevent subsequent liver failure.