【作者】 王俊；

【导师】 谢俊霞；

【作者基本信息】 青岛大学 ， 生理学， 2002， 硕士

【摘要】 帕金森病(PD)是一种常见的神经系统功能紊乱症，以运动不能、肌强直、静止性震颤及姿势异常为典型的临床表现。PD最主要的病理学特征为黑质致密带(SNc)多巴胺(DA)能神经元脱失及伴发的纹状体(CPu)轴突末梢DA的耗竭。为阐明导致黑质(SN)DA能神经元变性的原因，神经科学家们进行了长期广泛深入的研究，大量的实验证实，PD病人SN内铁含量增高，铁参与自由基的生成，导致神经细胞死亡，因此脑内铁含量增高被认为参与了PD的发病。6-OHDA单侧损毁大鼠是目前研究PD公认的及经典的动物模型。6-OHDA单侧损毁SN-CPu DA系统至少1周才出现阿朴吗啡诱发的旋转行为及运动失调。因此，众多研究大多是6-OHDA单侧损毁大鼠内侧前脑束(MFB)或CPu后1周以上，CPu内DA含量下降90％以上的研究。然而组织化学、神经化学的变化，几乎在6-OHDA注射后立即发生，因此我们应用6-OHDA单侧损毁MFB后观察急性期内SN与CPu组织化学、神经化学、电化学的变化情况。以期为铁与PD之间的关系提供新的实验资料。本研究应用国内率先引进的快速周期伏安法(FCV)在体动态监测了6-OHDA单侧损毁大鼠电刺激MFB诱发的CPu的DA释放，应用原子吸收分光光度计及铁染色技术测定了SN中铁的变化，以及应用酪氨酸羟 扫要 大鼠黑质多巴胺能神经元损伤与铁浓度关系的电化学和组织化学实验研究 化酶（TH）免疫组织化学技术观察了SN内DA神经元损毁情况。结 果表明： 1．6－OHDA单侧损毁MFB天后，SN内TH阳性细胞下降了 45％，3天后下降66％。 2．6－OHDA单侧损毁回FB天后，SN内铁染色增强，损毁后 1 天与3天相比染色强度的差别无统计学意义。 3．6－OHDA单侧损毁MFB天后，SN内铁浓度增加，损毁后 1天与3天相比染色强度的差别无统计学意义。 《．6－OHDA单侧损毁MFB天与3天后，损毁侧CPU内OA释 放量与未损毁侧及正常鼠相比差别无统计学意义。 上述结果提示：19．spg／5．SPI6－OHDA单侧损毁MFB天 后，可造成45％ SN内TH阳性细胞的下降，铁浓度增加，但CPU内 DA释放量无变化。据己有研究报道证实只有当90％以上的中脑DA 能神经元变性死亡时，才会出现临床症状。可见DA能神经系统巨 大的代偿作用掩盖了PD临床症状的进展过程。本实验从制备的 6－OHDA单侧损毁MFB模型大鼠的急性期着手，通过其组织化学、 神经化学和电化学的变化，为脑内高铁与PD的关系提供了可靠的 实验资料，并为临床上早期应用铁螫合剂提供了一定的实验依 据。更多还原

【Abstract】 Parkinson’s disease is a progressive neurodegenerative disorder associated with the loss of dopamine neurons originating in the zona compacta of the substantia nigra (SNc) and terminating in the caudate and putamen (CPu). This disorder is characterized symptomatically by akinesia, tremor and rigidity. Extensive studies have indicated that iron levels increased in the SN of parkinsonian patients, and this metal catalyzes the fomation of free radicals which participate in the cascade of events ending in cell death. The increase of iron content may be involved in the etiology of PD. 6-OHDA unilaterally lesioned rat is believed to be a classic model of PD. Typically, rats develop unilateral movement deficiencies coupled with apomorphine-induced rotation behavior at least one week after an ipsilateral 6-OHDA lesion of the nigrostriatal dopamine (DA) system. So, most studies have concentrated on long-term behavioral and morphological effects that occur one week following the administration of 6-OHDA, or when dopamine (DA) loss exceeds 90% of total dopamine in the CPu. However, neuroanatomical and biochemical changes likely appear almost immediately upon administration and uptake of 6-OHDA. Thus we utilized the 6-OHDA unilaterally lesioned rats in the present study to investigate the acute time course of changes of histochemistry,neurochemistry and electrochemistry in SN and CPu. Using fastcyclic Voltammetry (FCV), we monitored DA release from caudate putamen (CPu) of 6-OHDA unilaterally lesioned rats. DA release was evoked by electrical stimulation of medial forbrain bundle (MFB). Additionally, the changes of iron in SN was measured by Atomic Absorption/Flame Emission Spectrophotometer and iron staining. Using tyrosine hydroxylase (TH) immunochemistry , we examined cell death in the SN. The results are as follows:1. One day after a unilateral 6-OHDA injected into MFB, there was a 45% reduction in the density of TH immunoreactive cells on the lesioned side. Three days after the 6-OHDA injection, 66% reduction was observed.2. One day after a unilateral 6-OHDA injected into MFB, the SN of lesioned side showed an increase in iron staining intensity in comparision with the contralateral unlesioned side and normal rats. There was no difference in iron staining of lesioned side between groups of one day postlesioning and three days postlesioning.3. One day after a unilateral 6-OHDA injected into MFB, iron concentration increased in ipsilateral SN compared with contralateral unlesioned side and normal rats.There was no difference in iron concentration of lesioned side between one day postlesioning and three days postlesioning.4. One day or three days after a unilateral 6-OHDA injected into MFB, the DA release in CPu of lesioned side did not change,Abstract Electrochemical and Hisochemical Study on Relationship... compared with the normal and nonlesioned side.Taking these together, it suggests that one day after 6-OHDA(19.8ug/5.5ul) injected into MFB, there is a 45% reduction in the density of TH immunoreactive cells on the lesioned side, and nigral iron increases while DA release in CPu does not change.It has been confirmed that gross behavial deficits do not occur unless more than 90% of dopaminergic neurons have degenerated. That means, immence compensatory mechanism of DA system have covered the process of PD. So with the 6-OHDA unilaterally lesioned rat to examine the acute time course of changes of histochemistry, neurochemistry and electrochemistry in SN and CPu, our study provides experimental evidence for the relationship between iron and PD, and suggests using chelator in the early stage of the disease to reduce high brain iron might be a strategy for the prevention and treatment of PD.更多还原