Title: Dielectric properties of chondrocytes in a changing environment.

描述(申请人提供)：软骨细胞是唯一产生软骨的细胞类型，占据着独特的生物电环境。机械负荷通过细胞周围离子和水含量的快速变化来产生生物电刺激。软骨细胞对离子梯度变化的反应在细胞外基质的调节中起着重要作用。 综合。细胞的异常反应可能会导致蛋白质的异常沉积，导致组织退化，从而导致病理后果。通常，对跨细胞膜的离子和渗透梯度的反应是通过离子在通道中的移动来维持细胞的平衡。软骨细胞具有与电刺激组织相同的离子通道阵列，但软骨细胞电生理学的研究还很少。离子通道在软骨细胞中的存在现在变得越来越明显，然而，对人类软骨细胞的广泛研究以及潜在的通道缺陷如何与疾病相关的研究还不够深入。这一建议将实时量化细胞膜和细胞质的介电性质，以响应与离子通道基因表达相关的细胞电化学变化。我们假设软骨细胞对环境变化的介电反应将依赖于离子通道的活性。这项建议的目的是(1)使用一种新型微流控装置，实时记录软骨细胞在渗透压、pH和离子流量变化时的介电变化。(2)检测软骨细胞离子通道基因表达作为对这些变化的反应。(3)软骨细胞在低氧条件下功能正常。我们将直接比较正常和低氧条件下的介电响应，并确定低氧条件下软骨细胞中活跃的离子通道。据我们所知，我们的结果将是第一次描述真实测量的软骨细胞的介电性质 缺氧状态下离子通道的表达与时间相关，并将通过离子通道反应从根本上影响软骨生物，统一软骨内的生物力学和生物电学事件。

DESCRIPTION (provided by applicant): Chondrocytes, the only cell type that produces cartilage, occupy a unique bioelectrical environment. Mechanical load generates bioelectrical stimulation through rapid changes in ionic and water content around cells. A chondrocytes response to changing ionic gradients plays an essential role in regulation of extra cellular matrix synthesis. An abnormal response by the cell may result in abnormal deposition of proteins leading to degeneration of tissue with pathological consequences. Typically, response to ionic and osmotic gradients across cell membranes is by ion movement through channels as a cell reacts to maintain equilibrium. Chondrocytes possess an array of ion channels on par with electrically excitable tissues, yet chondrocyte electrophysiology is much understudied. Ion channel presence in chondrocytes is now becoming apparent, however, extensive studies in human chondrocytes and how potential channel defects relate to disease are understudied. This proposal will quantify in real time dielectric properties of the membrane and cytoplasm in response to electrochemical changes to cells related to ion channel gene expression. We hypothesize that dielectric response of chondrocytes to changes in environment will be dependent upon ion channel activity. The objectives of this proposal are (1) to document dielectric changes in chondrocytes in real time when exposed to changes in osmolality, pH and ion flow using a novel microfluidic device. (2) Measure gene expression of ion channels in chondrocytes as a response to these changes. (3) Chondrocytes function under hypoxic conditions. We will directly compare dielectric response under normal versus hypoxic conditions and identify ion channels active in chondrocytes under hypoxic conditions. To our knowledge, our results will be the first description of dielectric properties of chondrocytes measured in real time and correlated to ion channel expression under hypoxia and will fundamentally impact cartilage biology unifying biomechanical and bioelectrical events in cartilage through ion channel response.