The inhalation anesthetic isoflurane increases levels of proinflammatory TNF-α, IL-6, and IL-1β

Anesthetics have been reported to promote Alzheimer's disease (AD) neuropathogenesis by inducing beta-amyloid protein accumulation and apoptosis. Neuroinflammation is associated with the emergence of AD. We therefore set out to determine the effects of the common anesthetic isoflurane on the levels of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-1 beta, the proinflammatory cytokines, in vitro and in vivo, employing Western blot, immunohistochemistry, enzyme-linked immunosorbent assay (ELISA), and reverse transcriptase polymerase chain reaction (RT-PCR). Here, we show that a clinically relevant isoflurane anesthesia increased the protein and messenger ribonucleic acid (mRNA) levels of TNF-alpha, IL-6, and IL-1 beta in the brain tissues of mice. The isoflurane anesthesia increased the amounts of TNF-alpha immunostaining positive cells in the brain tissues of mice, the majority of which were neurons. Furthermore, isoflurane increased TNF-alpha levels in primary neurons, but not microglia cells, of mice. Finally, isoflurane induced a greater degree of TNF-alpha increase in the AD transgenic mice than in the wild-type mice. These results suggest that isoflurane may increase the levels of proinflammatory cytokines, which may cause neuroinflammation, leading to promotion of AD neuropathogenesis. (C) 2012 Elsevier Inc. All rights reserved.