Yang In Hong, Siddique Rezina, Hosmane Suneil, Thakor Nitish, Höke Ahmet
Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
Exp Neurol. 2009 Jul;218(1):124-8. doi: 10.1016/j.expneurol.2009.04.017. Epub 2009 May 3.
Chemotherapy induced peripheral neuropathy is a common and dose-limiting side effect of anticancer drugs. Studies aimed at understanding the underlying mechanism of neurotoxicity of chemotherapeutic drugs have been hampered by lack of suitable culture systems that can differentiate between neuronal cell body, axon or associated glial cells. Here, we have developed an in vitro compartmentalized microfluidic culture system to examine the site of toxicity of chemotherapeutic drugs. To test the culture platform, we used paclitaxel, a widely used anticancer drug for breast cancer, because it causes sensory polyneuropathy in a large proportion of patients and there is no effective treatment. In previous in vitro studies, paclitaxel induced distal axonal degeneration but it was unclear if this was due to direct toxicity on the axon or a consequence of toxicity on the neuronal cell body. Using microfluidic channels that allow compartmentalized culturing of neurons and axons, we demonstrate that the axons are much more susceptible to toxic effects of paclitaxel. When paclitaxel was applied to the axonal side, there was clear degeneration of axons; but when paclitaxel was applied to the soma side, there was no change in axon length. Furthermore, we show that recombinant human erythropoietin, which had been shown to be neuroprotective against paclitaxel neurotoxicity, provides neuroprotection whether it is applied to the cell body or the axons directly. This observation has implications for development of neuroprotective drugs for chemotherapy induced peripheral neuropathies as dorsal root ganglia do not possess blood-nerve-barrier, eliminating one of the cardinal requirements of drug development for the nervous system. This compartmentalized microfluidic culture system can be used for studies aimed at understanding axon degeneration, neuroprotection and development of the nervous system.
化疗诱导的周围神经病变是抗癌药物常见的剂量限制性副作用。旨在了解化疗药物神经毒性潜在机制的研究一直受到缺乏合适培养系统的阻碍，这种系统无法区分神经元细胞体、轴突或相关神经胶质细胞。在此，我们开发了一种体外分隔微流控培养系统，以研究化疗药物的毒性位点。为了测试该培养平台，我们使用了紫杉醇，一种广泛用于治疗乳腺癌的抗癌药物，因为它在很大一部分患者中会导致感觉性多发性神经病变，且尚无有效治疗方法。在先前的体外研究中，紫杉醇会诱导远端轴突变性，但尚不清楚这是由于对轴突的直接毒性还是对神经元细胞体毒性的结果。利用允许对神经元和轴突进行分隔培养的微流控通道，我们证明轴突对紫杉醇的毒性作用更敏感。当将紫杉醇应用于轴突侧时，轴突出现明显变性；但当将紫杉醇应用于胞体侧时，轴突长度没有变化。此外，我们表明，重组人促红细胞生成素已被证明对紫杉醇神经毒性具有神经保护作用，无论将其直接应用于细胞体还是轴突，都能提供神经保护。这一观察结果对化疗诱导的周围神经病变神经保护药物的开发具有启示意义，因为背根神经节不具备血神经屏障，消除了神经系统药物开发的一项基本要求。这种分隔微流控培养系统可用于旨在了解轴突变性、神经保护和神经系统发育的研究。
