MD-2 is up-regulated in the liver from turpentine-treated mice and is dependent on IL-6. (A) MD-2 mRNA levels were measured in liver from C57BL/6 IL-6^+/+ and C57BL/6 IL-6^−/− mice 8 and 48 hours after paw injection of turpentine (turp) or normal saline (NS). Messenger RNA levels were measured by quantitative RT-PCR. Mean plus or minus SD MD-2 mRNA levels were normalized with the expression β-actin mRNA and expressed as arbitrary units. One experiment, 3 animals per group. (B) The MD-2 protein (green) is increased in liver from C57BL/6 wild type mice treated 8 hours with turpentine compared with mice treated with normal saline (NaCl 0.9%). MD-2 is up-regulated by hepatocytes because it colocalizes (merge, yellow) with albumin (red). The increased fluorescence is located in the perinuclear region of hepatocytes. No specific staining was observed with isotype controls in liver from turpentine-treated animals (bottom row). Bar equals 20 μm. Results were similar in 6 animals (3 per group).