IMPACT OF HEAVY METALS ON VESTIBULAR SENSORY ORGANS

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。人的内耳包含听觉和平衡器官。长期接触重金属会对内耳的听觉部分造成损害，导致听力丧失。暴露在这种环境下还会影响依靠微小碳酸钙晶体（耳蜗）发挥作用的平衡器官，从而导致儿童和成人身体失衡。耳膜的产生和功能是由所嵌入的蛋白质材料控制的。当有毒金属与耳郭的蛋白质基质结合时，可能导致微小晶体的形成异常，从而表现为听力和平衡障碍。为了了解重金属暴露对人类耳石生物矿化的影响，我们建议研究重金属，汞，镉和铅对鱼耳中类似生物矿（耳石）的毒性影响。耳石器官也是由碳酸钙构成的。耳石内的蛋白质物质控制着耳石的晶体形态和大小。该假说基于这样一个事实，即重金属通过直接沉积以及与有机基质（蛋白质）结合而与生物矿物质结合。根据接触量、特定金属的毒性和掺入量的不同，它们可能会抑制或改变耳石的正常发育和功能。为了验证这一假设，提出将斑马鱼暴露于水中的金属，然后将其耳石取出并进行金属分析，以阐明它们在无机和有机物质之间的水平和分布。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The inner ear in humans contains hearing and balance organs. Chronic exposure to heavy metals causes damages to auditory component of the inner ear resulting in hearing loss. Exposure also causes imbalance in children and adults by affecting the balance organ that functions with the aid of tiny calcium carbonate crystals (otoconia). The production and function of the otoconia are controlled by the protein material embedded. Toxic metals when incorporate into the protein matrix of the otoconia may cause abnormalities in the formation of the tiny crystals that is consequently manifested by hearing and balance disorders. To understand the impact of heavy metal exposure on the biomineralization of human otoconia, we proposed to investigate toxic impact of heavy metals, mercury, cadmium and lead, on similar biominerals (otoliths) in the ears of fish. Otolith organs are also made of calcium carbonate. The protein material within an otolith controls the crystal form and size of the otolith. The hypothesis based on the fact that heavy metals incorporate to biominerals by direct deposition as well as by binding to the organic matrix (proteins). Depending on the magnitude of exposure, toxicity of particular metal and levels incorporated, they may inhibit or alter the normal development and function of the otolith. To test the hypothesis, it was proposed that zebrafish would be exposed to the metals in water, then the otoliths would be removed and analyzed for the metals to elucidate their levels and distribution between inorganic and organic material.