Recombinant thrombomodulin prevents heatstroke by inhibition of high-mobility group box 1 protein in sera of rats.

Heatstroke, a severe inflammatory response disease, is a medical emergency characterized by high body temperature. The protein C anticoagulant system inhibits inflammation resulting from various causes. Thrombomodulin (TM), a widely expressed glycoprotein originally identified in vascular endothelium, is an important cofactor in the protein C anticoagulant system. We tested the hypothesis that TM could prevent acute inflammation induced by heat stress in a rodent model. Male Wistar rats received a bolus of 1 mg x kg of body weight of TM or saline injected into the tail vein, followed by heat-stress treatment (exposure to 42°C for 30 min). Serum concentrations of cytokines (IL-1β, IL-6, and TNF-α), NO, and high-mobility group box 1 (HMGB1) protein were measured at various time points after treatment. We observed a decrease in the levels of cytokines and HMGB1 protein in sera of TM-treated animals over time. Inhibition of NO overproduction by recombinant TM was observed during heat stress-induced inflammation. Because of the decline in inflammatory marker levels, TM ameliorated injury to various organs in the rat model of heat stress-induced acute inflammation. As TM exhibited a strong anti-inflammatory effect in a rat model of acute inflammation induced by heat stress, TM represents a potential therapeutic for heatstroke prevention or management in patients.