( R )-Ketamine ameliorates lethal inflammatory responses and multi-organ injury in mice induced by cecum ligation and puncture

Sepsis is a life-threatening organ dysfunction syndrome arising from infection-induced uncontrolled systemic inflammatory responses. Patients surviving severe sepsis also exhibit increased mortality due to enhanced vulnerability to infections. In this study, we examined whether ( R )-ketamine could prevent against lethal sepsis-induced systemic inflammation and inflammatory organ injury. Septic model was induced by cecal ligation and puncture (CLP) surgery on adult mice. ( R )-ketamine (10 or 15 mg/kg) was administrated intraperitoneally (i.p.) 24 h before and/or immediately after CLP. Combined prophylactic and therapeutic use of ( R )-ketamine (10 mg/kg), as well as either prophylactic or therapeutic use of ( R )-ketamine at a single dose of 15 mg/kg did not reduce 14-day mortality after CLP. However, combined prophylactic and therapeutic use of ( R )-ketamine (15 mg/kg) significantly increased 14-day survival rate, attenuated sepsis-induced marked drop in the rectal temperature and increase in the plasma levels of inflammatory cytokines [i.e., interleukin (IL)-6, IL-17A, tumor necrosis factor (TNF)-α, IL-1β, and IL-10] 12 h after CLP. Furthermore, ( R )-ketamine alleviated sepsis-induced increase in the organ injury markers such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), myocardial kinase (CK-MB), and creatinine 24 h after CLP. Moreover, the increased lung wet/dry weight ratio, pulmonary morphological injury and the pulmonary levels of inflammatory cytokines were also attenuated by ( R )-ketamine. Combined prophylactic and therapeutic use of ( R )-ketamine could attenuate systemic inflammation and inflammatory multi-organ injury in mice after CLP-induced lethal sepsis. Therefore, ( R )-ketamine would be a potential prophylactic and therapeutic drug for patients prone to sepsis.