Comparison of lactate and β-hydroxybutyrate in the treatment of concanavalin-A induced hepatitis.

Simple metabolites released during physical exercise and fasting like lactate (Lac) and β-hydroxybutyrate (BHB) have recently been shown to possess anti-inflammatory properties. However, the effects of these metabolites in immune mediated hepatitis are still unknown. Accordingly, we investigated the role of Lac, BHB and their combination on experimentally induced hepatic inflammation. Adult male mice were administered concanavalin A (Con A, 15 mg/kg, intravenous) for 12 h. In the treatment groups, mice were treated 1 h after Con A-intoxication with Lac (500 mg/kg, intraperitoneal), BHB (300 mg/kg, intraperitoneal) and their combination. The results demonstrated that Lac and BHB, especially when combined together, alleviated Con A-induced hepatocellular injury (ALT, AST and LDH) and necrosis (hematoxylin-eosin and electron microscopy). These beneficial effects correlated with attenuating Con A-induced elevation in hepatic oxidative stress parameters (MDA and NOx). Mechanistically, administration of Lac and BHB led to inhibition of Con A-induced phosphorylation of JNK and AMPK proteins in the liver to the same extent. These effects were concordant with curbing Con A-mediated overexpression of the pro-inflammatory cytokines TNF-α, IL-6 and IL-12 and activation of the transcription factor NF-κB. The marked anti-inflammatory properties of combining Lac and BHB were attributed to their cooperation in repressing immune cells (monocytes and neutrophils) infiltration to the liver. Unlike BHB, Lac administration markedly induced the reparative STAT3 and ERK phosphorylation in the livers of Con A-intoxicated mice at the early time point. In conclusion, the simultaneous use of Lac and BHB might be an auspicious strategy for limiting immune mediated hepatitis.