Abstract
The anti-inflammatory actions of sevoflurane postconditioning are suggested as an important mechanism of sevoflurane postconditioning-induced neuroprotection against cerebral ischemia. Here, we determined whether the anti-inflammatory effects of sevoflurane postconditioning were mediated via inhibition of the toll-like receptor (TLR)-4/nuclear factor kappa B (NF-κB) pathway after global transient cerebral ischemia in rats. Forty-five rats were randomly assigned to five groups as follows: (1) control (10 min of ischemia, n = 10); (2) sevoflurane postconditioning (two periods of sevoflurane inhalation after ischemia for 10 min with a wash period of 10 min, n = 10); (3) resatorvid (intraperitoneal injection of a selective TLR-4 antagonist (3 mg/kg) 30 min before ischemia, n = 10); (4) sevoflurane postconditioning plus resatorvid (n = 10), and sham (n = 5). The numbers of necrotic and apoptotic cells in the hippocampal CA1 region, the expression levels of TLR-4, NF-κB, cleaved caspase-3, and tumor necrosis factor alpha (TNF-α) in the anterior part of each brain, and the serum levels of TNF-α, interleukin 6 (IL-6), and interleukin 1 beta (IL-1β) were assessed 1 day after ischemia. The necrotic cell counts and expression levels of TLR-4, NF-κB, caspase-3, and TNF-α in brain tissue as well as serum levels of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) were significantly higher in the control group than in the other groups. Our findings suggest that the anti-inflammatory actions of sevoflurane postconditioning via inactivation of the TLR-4/NF-κB pathway and subsequent reduction in pro-inflammatory cytokine production, in part, contribute to sevoflurane postconditioning-induced neuroprotection after global transient cerebral ischemia in rats.