BLOOD BRAIN BARRIER CHANGES INDUCED BY PAIN

描述(申请人提供)：在美国，慢性疼痛每年影响近7000万人，并造成数十亿美元的医疗成本和生产力损失。到目前为止，所有关于血脑屏障(BBB)和止痛药输送的研究都是在幼稚的非疼痛动物身上进行的。越来越清楚的是，血脑屏障不是一个静态的屏障，而是可以受到免疫、神经和激素系统的许多因素的调节。 疼痛时，这三个系统都会被激活。这项研究的假设是，疼痛激活了免疫、神经和激素系统，导致血脑屏障中分子和功能特性的改变。这种改变将导致物质通过血脑屏障的运输发生变化，并可能在慢性疼痛的病因中发挥作用。 在初步研究中，我们已经看到，在三种外周疼痛模型(福尔马林、A-卡拉胶、完全弗氏佐剂)中，大鼠血脑屏障的通透性增加到[S14C]蔗糖，只有在紧密连接受到损害的情况下，蔗糖才会穿过血脑屏障。在平行的Western印迹研究中，我们观察到occiudin(一种完整的血脑屏障紧密连接蛋白)减少，而ZO-1和肌动蛋白(分别是一种辅助蛋白和细胞骨架蛋白)增加。这表明疼痛改变了血脑屏障紧密连接。酶联免疫吸附试验和核糖核酸酶保护试验表明，在A-角叉菜胶诱导的疼痛过程中，外周血中的肿瘤坏死因子-α和中枢神经系统中的肿瘤坏死因子-α、干扰素-γ和白介素5和6的水平发生了时间依赖性的变化。所有这些物质之前都被证明可以改变紧密连接蛋白。因此，本研究旨在综合运用生理学、分子生物学和药理学的工具，进一步研究疼痛引起的变化以及促进这些变化的机制。我们的长期目标是寻找能够治疗血脑屏障这些变化的药理药物。

DESCRIPTION (provided by applicant): Chronic pain affects nearly 70 million people a year in the United States and costs billions of dollars in medical treatment and lost productivity. To date, all investigations concerning the blood-brain barrier (BBB) and the delivery of analgesics have been performed in naive non-pained animals. It is becoming increasingly clear that the blood-brain barrier is not a static barrier but can be modulated by a number of factors from the immune, neuronal and hormonal systems. During pain all three of these systems are activated. The hypothesis of this study is that pain activates the immune, neuronal and hormonal systems leading to an alteration in the molecular and functional properties in the blood-brain barrier. This alteration will lead to a change in the transport of substances across the blood-brain barrier and may have a role in the etiology of chronic pain. In preliminary studies, we have seen an increase in the permeability of the rat blood-brain barrier during three models of peripheral pain (Formalin, A-carrageenan, Complete Freunds Adjuvant) to [S14C] Sucrose which will only cross the blood-brain barrier if the tight junctions have been compromised. In parallel Western blot studies we observed a reduction in occiudin (an integral BBB tight junction protein) and an increase in ZO-1 and actin (an accessory and cytoskeletal protein respectively). This indicates that the pain has altered BBB tight junctions. ELISA and ribonuclease protection assays, show that levels of TNF-a in peripheral blood and TNF-a, IFN-gamma, and interleukins 5 and 6 are altered in the CNS in a time dependent manner during A-carrageenan induced pain. All of these substances have previously been shown to alter tight junction proteins. Therefore, this proposal is designed to further investigate the changes induced by pain and the mechanisms that promote these changes by utilizing the tools of physiology, molecular biology and pharmacology in an integrative manner. It is our long-term aim to identify pharmacological agents that can treat these alterations in the blood-brain barrier.