Ketamine suppresses intestinal TLR4 expression and NF-kappaB activity in lipopolysaccharide-treated rats.

AIM To investigate whether ketamine suppresses lipopolysaccharide (LPS)-induced increase in Toll-like receptor 4 (TLR4) expression and nuclear factor-kappa B (NF-kappaB) activity in the intestines of rats. METHODS Six groups of rats received one of the following: normal saline control, LPS (5 mg/kg) plus saline, LPS (5 mg/kg) plus ketamine (0.5 mg/kg), LPS (5 mg/kg) plus ketamine (2.5 mg/kg), LPS (5 mg/kg) plus ketamine (10 mg/kg), or ketamine (10 mg/kg) alone. Intestinal TLR4 mRNA expression was analyzed by reverse transcription polymerase chain reaction (RT-PCR), and NF-kappaB activity was tested by electrophoretic mobility shift assay (EMSA) 1, 3, or 5 hours after the LPS injection. RESULTS Lipopolysaccharide increased TLR4 expression and NF-kappaB activity in the intestines of rats. Ketamine at the dosage of 0.5, 2.5, and 10 mg/kg suppressed the LPS-induced increase in TLR4 expression and NF-kappaB activity. Ketamine alone had no effect. CONCLUSION The study demonstrated that ketamine inhibits NF-kappaB activation in the intestines of LPS-treated rats, possibly by suppressing TLR4 expression.