Mechanism of Bone Destruction Due to Middle Ear Cholesteatoma : Experimental Study

中耳胆脂瘤所致骨质破坏的详细机制仍不清楚。在这项研究中，我们使用激光拉曼光谱在分子水平上研究组织，并基于我们的结果，提出了一个假说来解释与胆脂瘤相关的慢性中耳炎的骨破坏过程。在这种破坏中，再矿化可能与脱矿一起发生，在中等酸性条件下，羟基磷灰石[Ca_&lt；10&gt；(PO_4)_6(OH)_2：HoAp]或其类似物可能沉积在被破坏的骨表面[Otologia(Fukuoka)1983，Am J Otolaryngol 1988]。为了简化模型系统，我们注意到了HOAP，它主要由成熟骨的无机成分组成，并将HOAP作为骨矿物成分的典型标本。作为实验标本，人工听小骨(Apaceram…更多地使用了由Hoap制造的产品。在这项研究中，我们利用激光拉曼光谱仪在分子水平上进行了脱矿和再矿化过程的模型实验。在活体实验中，无牙骨质盘被植入大鼠肩周区皮下。未经治疗的阿帕西仑作为对照。在体外实验中，我们连续测量了浸泡过Apaceram圆柱体的盐水溶液中释放的离子。研究结果如下：1.APACERAM表面：HOAP中不仅有PO_4~(2-)和~(3-)Gt~(2+)，而且有极少量的磷酸盐存在。(2)在体外实验中，Apaceram表面离子的溶解随着时间的延长而增加，Apaceram表面在植入后6个月开始脱矿，而非HoAP的磷酸盐在植入后10个月开始析出。2.与Apaceram表面接触的组织：在皮下组织中观察到3个月的未成熟骨和6个月或10个月的骨样物质较多。这些数据意味着HOAP的沉积是随着时间的推移而发展的。作为大鼠模型模拟的结果，激光拉曼光谱证实了APACERAM表面的脱矿和再矿化。综上所述，考虑到HOAP是成熟骨的主要无机成分，从分子水平分析的实验数据将支持我们关于慢性中耳炎与胆脂瘤相关的骨破坏机制的比例假说。较少

Details of the mechanism of bone destruction due to middle ear cholesteatoma still remain obscure. In this study, we used laser-Raman spectroscopy to study tissue at the molecular level and based on our results, proposed a hypothesis to explain the process of bone destruction occurring in chronic otitis media associated with cholesteatoma. In this destruction, remineralization may take place in combination with demineralization, and hydroxyapatite [Ca_<10>(PO_4)_6(OH)_2 : HOAP] or its analogues may be deposited on the destroyed bone surface under mildly acidic conditions [Otologia (Fukuoka) 1983, Am J Otolaryngol 1988].To obtain basic data to verify this hypothesis, model simulation in vivo and in vitro were performed. In order to simplify the model system, we paid attention to HOAP,which largely consists of inorganic constituents of mature bone and regarded HOAP as typical specimen of the mineral component of the bone. As the experimental specimen, synthetic auditory ossicle (Apaceram … More ^<<encircledR>>) made from HOAP was employed. In this study, we present model experiment for the de- and remineralization processes at molecular level using a laser-Raman spectrometer.In vivo experiment, the Apaceram discs were implanted subcutaneously into the interscapular region of rats. Untreated Apaceram was observed as a control. In vitro experiment, we carried out consecutive measurement of the ions released in saline solution in which cylinders of Apaceram had been immersed. Results are as follows : 1. Apaceram surface : not only PO_4^<3-> of HOAP but also very small amounts of phosphate were considered to be present. (2) dissolution of ions from Apaceram surface had been increased with time in vitro experiment and demineralization of Apaceram surface had been progressed at 6 months after implantation and in contrast, precipitation of phosphate other than HOAP had occurred at 10 months after implantation. 2. Tissue in contact with Apaceram surface : the more immatured substances like bone at 3 months and osseou substances at 6 or 10 months were observed on the subcutaneous tissue. These data mean that deposition of HOAP progressed with time after implantation.As a result of model simulation in rats de- and remineralization were demonstrated on the Apaceram surface by laser-Raman spectrometry.In conclusion, our proporsed hypothesis on the bone destruction mechanism due to chronic otitis media associated with cholesteatoma will be supported by the experimental data analyzed at molecular level, considering HOAP which is the main inorganic constituent of mature bone. Less