Ulinastatin is a novel candidate drug for sepsis and secondary acute lung injury, evidence from an optimized CLP rat model.

Ulinastatin is a potent multivalent serine protease inhibitor, which was recently found with therapeutic potentials in treating sepsis, and the most life-threatening complication of critically ill population. However, the pharmacological features and possible mechanisms need to be further elucidated in reliable and clinical relevant sepsis models. As known, sepsis induced by surgery of cecal ligation and puncture (CLP) is widely accepted as the gold standard animal model, but the inconsistency of outcomes is the most obvious problem. In the present experiments, we reported an improved rat CLP model with much more consistent outcomes using self-made three edged puncture needles in our lab. Results from this optimized model revealed that ulinastatin improved survivals of CLP rats, attenuated proinflammatory response and prevented systemic disorder and organ dysfunction. Ulinastatin was also found to be effective in ameliorating sepsis-related ALI, a syndrome most frequent and fatal in sepsis. The molecular mechanism investigation showed that ulinastatin's protection against ALI was probably related to the down-regulation of NF-κB activity and inhibition of TNF-α, IL-6 and elastase expressions in the lung tissue. In conclusion, based on a successful establishment of optimized rat CLP model ulinastatin is proved to be an effective candidate for sepsis treatment, due to its anti-inflammation and anti-protease activities that ameliorate systemic disorders, prevent organ injuries and thus improve the survival outcomes of sepsis in animals.