吗啡依赖大鼠不同脑区肌动蛋白及其结合蛋白的表达变化

目的研究吗啡依赖大鼠不同脑区肌动蛋白及其结合蛋白p-cofilin的表达变化。方法 42只♂SD大鼠,随机分为吗啡依赖1周组(M1组)、2周组(M2组)和4周组(M4组),各依赖组均设对照,每组7只。吗啡依赖组采用剂量递增法腹腔注射吗啡,每日3次,连续7 d,日剂量按5,10,15,20,30,40,50 mg.kg-1逐日递增,对照组给与等体积的生理盐水。M2和M4组大鼠继续分别给予50 mg.kg-1盐酸吗啡,每天1次,连续注射1或3周。在最后一次给药后5 h断头处死大鼠,迅速分离前额叶皮质、海马、纹状体和丘脑。Western blot检测吗啡依赖大鼠不同脑区肌动蛋白及其结合蛋白的表达变化。结果与对照组相比,M2和M4组大鼠前额叶皮质内F-actin/G-actin比值分别上调53%(P<0.05)和102%(P<0.01);M2和M4组大鼠前额叶皮质内p-cofilin表达量分别上调93%(P<0.01)和88%(P<0.01)。M4组大鼠海马中F-actin/G-actin比值上调94%;M2和M4组大鼠海马中p-cofilin蛋白表达量分别上调45%(P<0.05)和30%(P<0.05)。M2和M4组大鼠纹状体内p-cofilin的蛋白表达量分别下调25%(P<0.05)和30%(P<0.05)。结论长期吗啡处理可诱导大鼠形成依赖,伴随着依赖相关脑区肌动蛋白重构,并呈现脑区特异性和时间依赖性。

Changes in the expression of actin and actin-binding protein in the brain of morphine dependent rats

Aim To investigate the expression of actin and actin-binding protein p-cofilin in several brain regions of morphine dependent rats.Methods Fourty-two male SD rats were randomly divided into morphine dependent 1 week group(group M1),morphine dependent 2 weeks group(group M2) and morphine dependent 4 weeks group(group M4) with 7 animals in each group.Every morphine dependent group had corresponding control group.In morphine dependent group the animals were given intraperitoneally increasing doses of morphine starting from 5,10,15,20,30,40,50 mg·kg-1 three times a day for 7 days.Rats in control group received the equal volume of saline.In group M2 and group M4 the animals received continuously 50 mg·kg-1 morphine injection once a day for 1 or 3 weeks respectively.Rats were sacrificed by decapitation 5 hours after the last injection.The brain regions including prefrontal cortex,hippocampus,striatum and thalamus were separated and frozen until assay.The expression of actin and actin-binding protein p-cofilin in several brain regions of rats were determined by Western blot.Results Compared with the control group,the ratio of F-actin to G-actin in prefrontal cortex of group M2 and group M4 was up-regulated by 53%(P<0.05) and 102%(P<0.01) respectively.The expression of p-cofilin in prefrontal cortex of group M2 and group M4 was up-regulated by 93%(P<0.01) and 88%(P<0.01) respectively.The ratio of F-actin to G-actin in hippocampus of group M4 was up-regulated by 94%(P<0.01).The expression of p-cofilin in hippocampus of group M2 and group M4 was up-regulated by 45%(P<0.05)and 30%(P<0.05)respectively.The expression of p-cofilin in striatum of group M2 and group M4 was down-regulated by 25%(P<0.05)and 30%(P<0.05)respectively.Conclusion Chronic morphine treatment can induce the development of morphine dependence,which accompanies with actin rearrangments in the brain of rats in time-dependent and brain region-dependent way.