Wu Yuqing, Li Wei, Zhou Ce, Lu Fuzhao, Gao Tianhui, Liu Yingchun, Cao Junli, Zhang Yongmei, Zhang Yong, Zhou Chenghua
Department of Anesthetic Pharmacology, Xuzhou Medical College, Xuzhou, PR China.
Cell Physiol Biochem. 2012;30(3):609-17. doi: 10.1159/000341442. Epub 2012 Jul 27.
BACKGROUND/AIMS: Ketamine has been reported to exert anti-inflammatory effects on astrocytes stimulated by lipopolysaccharide (LPS) in vitro and in vivo. However, the mechanism has not been elicited clearly. The aim of this study was to investigate the effects of ketamine on TLR4 expression and NF-ĸB-p65 phosphorylation, as well as the production of proinflammatory cytokines in LPS challenged astrocytes.
Astrocytes were stimulated with LPS (1µg/ ml) in the absence and presence of various concentrations of ketamine (10, 100, 1000µM). The concentrations of IL-1β, IL-6 and TNF-α were measured by ELISA, the expression of glial fibrillary acidic protein (GFAP) in astrocytes was detected by immunofluorescence staining, the level of phosphorylated NF-ĸB p65 and the expression of TLR4 were detected by western blotting.
LPS increased TLR4 expression and the phosphorylation of NF-ĸB p65 subunit as well as GFAP expression and the production of IL-1β, IL-6 and TNF-α in cultured astrocytes. Ketamine (100 and 1000 µM) reduced the expression of GFAP and the production of these proinflammatory cytokines, inhibited the expression of TLR4 and attenuated the phosphorylation of NF-ĸB p65 in astrocytes challenged by LPS.
The inhibitory effects of ketamine on LPS-induced astrocytes activation and inflammation response may be mediated by suppressing NF-ĸB activation through reducing the expression of TLR4.
背景/目的：据报道，氯胺酮在体外和体内对脂多糖（LPS）刺激的星形胶质细胞具有抗炎作用。然而，其机制尚未明确。本研究旨在探讨氯胺酮对LPS刺激的星形胶质细胞中Toll样受体4（TLR4）表达、核因子-κB p65（NF-κB-p65）磷酸化以及促炎细胞因子产生的影响。
在存在和不存在不同浓度氯胺酮（10、100、1000μM）的情况下，用LPS（1μg/ml）刺激星形胶质细胞。通过酶联免疫吸附测定法（ELISA）检测白细胞介素-1β（IL-1β）、白细胞介素-6（IL-6）和肿瘤坏死因子-α（TNF-α）的浓度，通过免疫荧光染色检测星形胶质细胞中胶质纤维酸性蛋白（GFAP）的表达，通过蛋白质免疫印迹法检测磷酸化NF-κB p65的水平和TLR4的表达。
LPS增加了培养的星形胶质细胞中TLR4的表达、NF-κB p65亚基的磷酸化以及GFAP的表达和IL-1β、IL-6和TNF-α的产生。氯胺酮（100和1000μM）降低了GFAP的表达和这些促炎细胞因子的产生，抑制了TLR4的表达，并减弱了LPS刺激的星形胶质细胞中NF-κB p65的磷酸化。
氯胺酮对LPS诱导的星形胶质细胞活化和炎症反应的抑制作用可能是通过降低TLR4的表达来抑制NF-κB的激活介导的。
