Objective To observe the changes of N-methyl-D-aspartate (NMDA) receptor 2B subunit (NR2B) expression in the striatum of chronic alcohol exposured rats at different withdrawal time.Methods 72 male Wistar rats were randomly divided into withdrawal 2h group,withdrawal 6h group,withdrawal 12h group,withdrawal 1d group,withdrawal 3d group and control group,and 12 rats in each group.In the 5 withdrawal groups,ethanol was administered in drinking water at the concentration of 6％ (V/V) for 16 weeks,and rats in control group were maintained with water.After 16 weeks ethanol was removed and ethanol withdrawal syndromes were evaluated.The expression of NR2B protein in the striatum was measured by immunofluorescence and western blot and the expression of NR2B mRNA in the striatum was measured by realtime PCR.Results Compared with withdrawal scores of control group((1.50±0.80)),scores of withdrawal 2h,6h,12h,1d,3d groups ((10.42±2.50),(15.42± 1.93),(9.25±2.01),(7.67± 1.92),(2.25±0.87) respectively) were higher,and the withdrawal scores of withdrawal 6h group were the highest.Compared with the expression of NR2B fluorescence intensity (2210.00± 178.20),the expression of NR2B protein(0.150±0.009) and the expression of NR2B mRNA(0.006±0.001) in the striatum of control group,the expression of NR2B fluorescence intensity (2710.56 ± 194.21),(5035.16 ± 234.41),(3326.23 ± 378.16),(2570.64 ±177.88),the expression of NR2B protein (0.192±0.008),(1.649±0.205),(0.783±0.109),(0.180±0.009) and the expression of NR2B mRNA (0.026±0.002),(0.351±0.034),(0.248± 0.023),(0.024±0.003) of withdrawal 2h,6h,12h,ld groups were significantly higher (P＜0.05),and with the extension of the withdrawal time,the expression was gradually increased.The expression of withdrawal 6h group was the highest,then began to decline,and returned to baseline levels at withdrawal 3 d(P＞0.05).Withdrawal scores were positively correlated with the expression of NR2B protein(r=0.719,P＜0.01),the expression of NR2B protein was positively correlated with the expression of NR2B mRNA(r=0.937,P＜0.01),and the expression of NR2B mRNA was positively correlated with withdrawal scores(r=0.673,P＜0.01).Conclusion The expression of NR2B was up-regulated in the striatum of chronic alcohol exposured rats at different withdrawl time.NR2B protein and NR2B mRNA expression is positively correlated with the withdrawal scores,suggesting that regulating the expression of NR2B may be a new target for the treatment of ethanol withdrawal symptoms.%目的 观察慢性酒精暴露后Wistar大鼠不同戒断时间点纹状体NMDA受体2B亚基(NMDA receptor 2B subunit,NR2B)表达的变化.方法 72只雄性Wistar大鼠,按照完全随机法分为戒断2h组、戒断6h组、戒断12h组、戒断1d组、戒断3d组和正常对照组,每组12只.5个戒断组大鼠自由饮用体积百分比为6％的酒精水溶液16周,正常对照组饮用纯净水16周.戒断组分别于末次饮酒后2h、6h、12h、1d、3d时,正常对照组于末次饮水后2h时,评估戒断症状后处死取纹状体,采用免疫荧光法和Western blot检测各组大鼠纹状体NR2B蛋白含量的表达,采用实时荧光定量PCR技术检测各组大鼠纹状体NR2B mRNA的表达.结果 与正常对照组戒断评分[(1.50±0.80)分]相比,戒断2h、6h、12h、1d、3d组大鼠戒断评分[(10.42±2.50)分、(15.42±1.93)分、(9.25±2.01)分、(7.67±1.92)分、(2.25±0.87)分]均增高,戒断6h组评分最高;与正常对照组大鼠纹状体NR2B荧光表达强度[(2210.00± 178.20)]、NR2B蛋白表达水平[(0.150±0.009)]及NR2B mRNA表达水平[(0.006±0.001)]相比,戒断2h、6h、12h、1d组NR2B荧光表达强度[(2710.56±194.21)、(5035.16±234.41)、(3326.23±378.16)、(2570.64±177.88)]、NR2B蛋白表达水平[(0.192±0.008)、(1.649±0.205)、(0.783±0.109)、(0.180±0.009)]及NR2BmRNA表达水平[(0.026±0.002)、(0.351±0.034)、(0.248±0.023)、(0.024±0.003)]均有明显增高(均P＜0.05),且随着戒断时间的延长,表达逐渐上升,至戒断6h达到高峰,其后开始下降,戒断3d恢复至基线水平(P＞0.05);戒断综合征评分与NR2B蛋白表达水平(r=0.719,P＜0.01)、NR2B蛋白表达水平与NR2B mRNA表达水平(r=0.937,P＜0.01)、NR2B mRNA表达水平与戒断综合征评分(r=0.673,P＜0.01)均呈正相关.结论 慢性酒精暴露后戒断大鼠前3d纹状体NR2B表达上调,NR2B蛋白和NR2B mRNA表达与戒断综合征评分呈正相关,调控NR2B表达可能是治疗酒依赖戒断症状的新靶点.
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