甲基苯丙胺与HIV-Tat蛋白协同致大鼠纹状体NMDA受体NR2B亚基和iNOS的表达

Expression of NMDA Receptor Subunit 2B and iNOS in Rat Striatum by Synergizing Methamphetamine and Human Immunodeficiency Virus Protein Tat

目的观察甲基苯丙胺(MA)与HIV-Tat蛋白协同作用致大鼠相关脑区N-甲基-D-天冬氨酸(NMDA)受体NR2B亚基和诱导型一氧化氮合成酶(iNOS)的表达变化,探讨MA与HIV-Tat协同作用对神经系统的影响.方法 50只健康雄性SD大鼠随机分为实验组:MA组(10 mg/kg MA,每日2次腹腔注射,连续4 d)、HIV-Tat组(10μg HIV-Tat注入大鼠脑纹状体)和MA+HIV-Tat组(按MA组注射MA 4 d后按HIV-Tat组注入HIV-Tat);对照组:生理盐水腹腔注射或纹状体内注射.各组大鼠分别于注射结束后48 h和7 d处死,麻醉后用多聚甲醛灌注,取出脑组织并固定,石蜡包埋,作冠状切面,用免疫组化和蛋白免疫印迹法对中毒大鼠纹状体中NMDA受体NR2B亚基和iNOS的表达进行观察,并进行图像分析,测量其平均光密度值,与对照组比较并进行统计学分析.结果各实验组与对照组比较,纹状体内NMDA受体NR2B亚基和iNOS的表达均有不同程度增高,差异具有统计学意义(P<0.05);其中MA+HIV-Tat组与MA组、HIV-Tat组比较,NMDA受体NR2B亚基和iNOS的表达显著增高(P<0.05).结论 MA与HIV-Tat蛋白的共同作用能够显著增加NMDA受体NR2B亚基和iNOS的表达,揭示NMDA受体NR2B亚基和iNOS参与了MA与HIV-Tat蛋白的协同神经毒性机制.

Objectives To observe the NMDA receptor subunit2B and iNOS expression in rat striatum by injected methamphetamine(MA)and HIV-Tat protein and to explore the synergies of MA and HIV-Tat on neural injury mechanisms.Methods A total of50healthy male SD rats were randomly divided into four groups:MA group which received intraperitoneal injection of10mg/kg MA by twice per day for4days,HIV-Tat group which received intrastriatal injection of10滋g HIV-Tat,MA+HIV-Tat group which received intraperitoneal injection of MA for4days and followed by intrastriatal injection of HIV-Tat),and control groups which received intraperitoneal or intrastriatal injection of saline.The rats were killed at48h or7d after the last time of injection.NMDA receptor subunit2B and iNOS expression were examined by using immunohistochemistry and western blotting.The results were analyzed and average optical density was measured.Results Compared with those in control group,NMDA receptor subunit2B and iNOS expression in rat striatum increased in the experimental groups(P<0.05).Compared with those in MA group or HIV-Tat group,NMDA receptor subunit2B and iNOS expression increased more significantly in MA+HIV-Tat group.Conclusion Synergies of MA and HIV-Tat protein can dramatically increase the expression of NMDA receptor subunit2B and iNOS.NMDA acceptor subunit2B and iNOS can participate in the process of MA and the HIV-Tat protein synergy nerve toxic mechanism.