[Effect of ketamine on endotoxin-induced septic shock in rats and its mechanism].

To explore the effect of ketamine on septic shock in rat and its mechanism.Sixty SD rats were randomly divided into control group, model group and ketamine group. Septic shock was replicated by intraperitoneal injection of 20 mg/kg lipopolysaccharide (LPS). Control group was given normal saline only. In ketamine group, the rats received intraperitoneal injection of 80 mg/kg ketamine 20 minutes before shock and 1 hour (ketamine 40 mg/kg) after shock. The survival time and survival rate were observed in each group. Serum tumor necrosis factor-alpha (TNF-alpha), myocardiac cyclic adenosine monophosphate (cAMP) were determined with radioimmunology assay, and expression of heat shock protein 70 (HSP70) was assessed by immunohistochemistry method.The survival rate was lower in model group (0) compared with control group (100%) and ketamine group (70%), the differences were significant (both P<0.05). TNF-alpha was higher, while cAMP was lower in model group compared with control group and ketamine group (all P<0.01). Positive expression of HSP70 in model group was lower than control group, while higher than ketamine group (both P<0.01). There were no significant differences in TNF-alpha and cAMP between control group and ketamine group (both P>0.05).Serum TNF-alpha is increased and myocardiac cAMP is decreased in LPS-induced septic shock, whereas ketamine can inhibit the effect of LPS and protect myocardium against sepsis probably by stimulating the expression of myocardiac HSP70.