BACKGROUND:Astrocytes participate in central nervous system-mediated physiological or pathological processes,such as pain.Activated dorsal horn astrocytes from the spinal cord produce nerve active substances and proinflammatory cytokines,such as interleukin-1beta(IL-1β),IL-6,and tumor necrosis factor-α(TNF-α),which play important roles in pain transduction and regulation.OBJECTIVE:To investigate the effects of different doses of propofol on activation of cultured spinal cord dorsal horn astrocytes induced by glutamate,as well as changes in IL-1β,IL-6,and TNF-α,and IL-10(anti-inflammatory cytokine) expression in rats,and to explore the dose relationship of propofol.DESIGN,TIME AND SETTING:The cellular and molecular biology experiment was performed at the Central Laboratory of Yunyang Medical College between March 2006 and December 2007.MATERIALS:Forty healthy,Wistar rats,aged 2-3 days,were selected.Propofol was provided by Zeneca,UK;glutamate by Sigma,USA;EPICS XL flow cytometry by Beckman culture,USA;rabbit-anti-mouse glial fibrillary acidic protein(GFAP) antibody kit and inflammatory cytokine detection kit were provided by Zhongshan Biotechnology Company Ltd.,Beijing;multimedia color pathologic image analysis system was a product of Nikon,Japan.METHODS:Astrocytes were harvested from T11-L6 spinal cord dorsal horn of Wistar rats and incubated for 3 weeks.The cells were divided into seven groups,according to various treatment conditions:control group was cells cultured in Hank’s buffered saline solution;intralipid group was cells cultured in intralipid(0.2 mL/L);glutamate group was cells cultured with 100 μmol/L glutamate;propofol group was cells cultured with 250 μmol/L propofol;three glutamate plus propofol groups were cultured in 100 μmol/L of glutamate,followed by 5,25,and 250 μmol/L of propofol 10 minutes later.MAIN OUTCOME MEASURES:GFAP-labeled astrocytes were analyzed using a multimedia pathology imaging analysis system to detect area density(AD) and average optical density(AOD) of positive cells.The supernatant concentrations of IL-1β,TNF-α,IL-6,and IL-10 were determined using radioimmune assays.RESULTS:Compared with the control group,cells in the glutamate plus low-dose propofol group were activated and hypertrophic,and AD and AOD were significantly increased(P < 0.01).Concentrations of IL-1 β,TNF-α,and IL-6 were also significantly increased(P < 0.01),while IL-10 levels remained unchanged(P > 0.05),but still higher than the control and glutamate groups(P > 0.05).Compared with the glutamate group,astrocyte activation was inhibited by moderate and high-dose propofol.In addition,with moderate and high-dose propofol,AD,AOD,IL-1β,TNF-α,and IL-6 concentrations were significantly decreased(P < 0.05-0.01),and IL-10 levels were increased(P < 0.01).CONCLUSION:Propofol can effectively inhibit glutamate-induced astrocyte activation in the spinal cord dorsal horn,significantly inhibit production of IL-1β,TNF-α,and IL-6,and increase IL-10 synthesis and release in a dose-dependent manner. BACKGROUND: Astrocytes participate in central nervous system-mediated physiological or pathological processes, such as pain. Activated dorsal horn astrocytes from the spinal cord produce nerve active substances and proinflammatory cytokines, such as interleukin-1 beta (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α), which play important roles in pain transduction and regulation. OBJECTIVE: To investigate the effects of different doses of propofol on activation of cultured spinal cord dorsal horn astrocytes induced by glutamate, as well as changes in IL-1β, IL-6, and TNF-α, and IL-10 (anti-inflammatory cytokine) expression in rats, and to explore the dose relationship of propofol. DIGNIGN, TIME AND SETTING: The cellular and molecular biology experiment was performed at the Central Laboratory of Yunyang Medical College between March 2006 and December 2007. SPECIALS: Forty healthy, Wistar rats, aged 2-3 days, were selected .ropofol was provided by Zeneca, UK; glutamate by Sigma, USA; EPICS XL flow cytometry by Beckman culture, USA; rabbit anti-mouse glial fibrillary acidic protein (GFAP) antibody kit and inflammatory cytokine detection kit were provided by Zhongshan Biotechnology Company Ltd., Beijing; multimedia color pathologic image analysis system was a product of Nikon, Japan. METHODS : Astrocytes were harvested from T11-L6 spinal cord dorsal horn of Wistar rats and incubated for 3 weeks. The cells were divided into seven groups, according to various treatment conditions: control group was cells cultured in Hank’s buffered saline solution; intralipid group was cells cultured in intralipid (0.2 mL / L); glutamate group was cells cultured with 100 μmol / L glutamate; propofol group was cells cultured with 250 μmol / L propofol; three glutamate plus propofol groups were cultured in 100 μmol / L of glutamate by 5,25, and 250 μmol / L of propofol for 10 minutes later. MAIN OUTCOME MEASURES: GFAP-labeled astrocytes were analyzed using a multimedia pathology imaging analysis system to detect area density (AD) and average oThe percentages of the supernatant concentrations of IL-1β, TNF-α, IL-6, and IL-10 were determined using radioimmune assays. RESULTS: Compared with the control group, cells in the glutamate plus low- Concentrations of IL-1β, TNF-α, and IL-6 were also significantly increased (P <0.01), while IL-10 levels remained unchanged (P> 0.05), but still higher than the control and glutamate groups (P> 0.05) .Compared with the glutamate group, astrocyte activation was inhibited by moderate and high-dose propofol. In addition, with moderate and high- dose propofol, AD, AOD, IL-1β, TNF-α, and IL-6 concentrations were significantly decreased (P <0.05-0.01), and IL- glutamate-induced astrocyte activation in the spinal cord dorsal horn, significantly inhibit production of IL-1β, TNF-α, and IL-6, and increase IL-10 synth esis and release in a dose-dependent manner.