吗啡戒断性焦虑大鼠海马突触界面结构及突触素表达变化

目的 探讨吗啡依赖戒断焦虑行为与海马CA1、CA3区突触界面结构和突触素表达变化之间的相关性.方法 剂量递增法建立大鼠吗啡依赖模型,高架十字迷宫检测焦虑行为,透射电镜技术结合图像分析系统、免疫组织化学比较对照组、模型组和治疗组(各6只)大鼠海马CA1、CA3区突触界面结构和突触素(P38)的表达.结果 (1)行为学:模型组开放臂的次数和时间均少于对照组和治疗组最小有意义差异t检验(下同),P＜0.01或P＜0.05).(2)突触界面结构:模型组CA1区突触后致密物厚度(10.7±0.9)nm]、突触活性区长度(45±4)am]、突触间隙宽度(3.80±0.30)nm]和突触界面曲率(1.37±0.12)均高于对照组和治疗组(P＜0.01或P＜0.05);模型组CA3区突触后致密物厚度(12.7±1.1)nm]、突触活性区长度(53±8)nm]、突触间隙宽度(3.81 ±0.59)nm]、突触界面曲率(1.39±0.30)亦均高于对照组和治疗组(P＜0.01或P＜0.05).(3)突触素表达:模型组CA1、CA3区突触素吸光度(A)值分别为(0.42±0.06)和(0.43±0.05),显著高于对照组(0.2±0.02,0.25±0.03)和治疗组(0.27±0.04,0.26±0.03).结论吗啡戒断焦虑行为与海马CA1、CA3区突触形态结构可塑性及突触素表达水平有一定的相关性.

Structural plasticity of synaptic interface structure and expression of synaptophysin in hippocampus in anxious rats suffered from morphine withdrawal

Objective For the hippocampal CA1 and CA3 regions,the possible relationship between structural plasticity of synaptic interface structure and expression of synaptophysin and their functional roles were explored in anxiety-behavioral rats.Methods The escalating doses of morphine and the elevated plus maze were applied to validate anxiety-like behavior in rats.Both electron microscopy and immunohistochemitry were applied to detect parameters,including structural plasticity of synaptic interface structure and expression of synaptophysin(P38),in the hippocampal fields CA1 and CA3 in control group,morphine-withdrawal group and cured group(n=6).Results (1)Anxiety-like behavioral symptoms were observed in the rats suffering from the escalating morphine doses(t,least significant difference test,P＜0.01 or P＜0.05).(2)Compared with control group and cured group,higher values of postsynaptic density (10.7±0.9)nm,length of postsynaptic thickening(45±4)nm,widths in synaptic interface structure on junctions(3.80±0.30)nm and curvature of the cleft region(1.37±0.12)nm were notably observed in hippocampal CA1 region in anxious rats(P＜0.01 or P＜0.05).Similarly,higher scores of postsynaptic density(12.9±1.1)nm,length of postsynaptic thickening(53±8)nm,widths in synaptic interface structure on junctions(3.81±0.59)nm and curvature of the cleft region(1.39±0.30)nm were detected in hippocampal field CA3 in anxious rats(P＜0.01 or P＜0.05).(3)Higher accumulated levels of synaptophysin were found in the hippocampal CA1 and CA3 regions in anxiety-behavioral rats(0.42±0.06and 0.43±0.05).Conclusion Our results suggested that structural plasticity of synaptic interface structure and expression of synaptophysin in the hippocampus could be contributed to development of drug addiction in rats.