Dose-related effects of dexmedetomidine on immunomodulation and mortality to septic shock in rats

摘要

BACKGROUND: Dexmedetomidine has already been used in septic patients as a new sedative agent, few studies have examined its effects on immunomodulation. Therefore, the authors have designed a controlled experimental study to characterize the immunomodulation effects of dexmedetomidine in the cecal ligation and puncture(CLP) model in rats. METHODS: After CLP, 48 Wistar rats were randomly allocated into four groups:(1) CLP group;(2) small-dose treatment group(2.5 g·kg^(-1)·h^(-1));(3) medium-dose treatment group(5.0 g·kg^(-1)·h^(-1)); and(4) large-dose treatment group(10.0 g·kg^(-1)·h^(-1)). HLA-DR and plasma cytokine(IL-4, IL-6, IL-10 and TNF-α) levels were measured, and the mean arterial blood pressure(MAP), heart rate(HR), arterial blood gases, lactate concentrations and mortality were also documented. RESULTS: The HLA-DR level, inflammatory mediator levels, MAP and HR had no obvious changes among Dexmedetomidine treatment groups(DEX groups). Compared with the CLP group, the DEX groups exhibited decreased HLA-DR levels(P_(group)=0.0202) and increased IL-6 production, which was increased at 3 h(P= 0.0113) and was then attenuated at 5 h; additionally, the DEX groups exhibited decreased HR(P<0.001) while maintaining MAP(P_(group)=0.1238), and remarkably improving lactate(P<0.0001). All of these factors led to a significant decrease in the mortality, with observed rates of 91.7%, 66.7%, 25% and 18% for the CLP, DEX2.5, DEX5.0, DEX10.0 groups, respectively.CONCLUSION: Dexmedetomidine treatment in the setting of a CLP sepsis rat model has partially induced immunomodulation that was initiated within 5 h, causing a decreased HR while maintaining MAP, remarkably improving metabolic acidosis and improving mortality dosedependently.