FUNCTIONAL AND MOLECULAR STUDY OF HUMAN MASSETER FIBERS

人体咬肌纤维的功能和分子研究

• 批准号: 2684007
• 负责人: JAMES J SCIOTE
• 金额: $ 9.9万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-04-01 至 2001-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2684007
• 关键词: SDS polyacrylamide gel electrophoresis; adenosinetriphosphatase; antibody; biopsy; cytoskeletal proteins; electron microscopy; gene expression; human tissue; immunocytochemistry; in situ hybridization; major histocompatibility complex; mastication; muscle function; muscle metabolism; muscle tension; myofibrils; myosins; polymerase chain reaction; protein isoforms; sarcomeres; systematic biology

DESCRIPTION (Adapted from the Applicant's Abstract): Mammalian skeletal muscle fibers have been traditionally classified into specific types by characterization of their myofibrillar ATPase and metabolic histochemistry and more recently by immunohistochemistry with myosin heavy chain (MHC)-specific antibodies. Human skeletal muscle contains three main fiber types: I, IIA and IIX (or IIB) derived from specific MHC isoforms. Mammalian jaw-closing muscle fibers are notably different in comparison to other skeletal muscle, reflecting the specialized nature of their functions. The jaw-closing muscle fibers of the human primate are the most exceptional, expressing developmental and cardiac MHC and myosin light chain (MLC) isoforms not found in other adult skeletal muscle, as well as the typical adult skeletal isoforms. A full description of myosin expression in human masseter is presently incomplete, and a fiber type classification scheme, incorporating both myosin protein content and contractile function, is lacking. Using human masseter muscle biopsies, the first specific aim of this study is to develop a fiber type classification scheme for jaw-closing muscles based on MHC and MLC identification as determined by tissue staining for: myofibrillar ATPase and metabolic histochemistry, immunohistochemistry with MHC-specific antibodies and in situ hybridization with probes developed from different MHC gene transcripts. In whole muscle biopsies and in single fibers, MHC content will be confirmed by glycerol-SDS- PAGE, and MLC content by 2-D electrophoresis. In addition, electron microscopy will be used to evaluate the relative heterogeneous distribution of myosin isoforms within representative fibers. The second aim of this study is to determine the maximum speed of unloaded shortening (Vo), as determined by the slack test, and specific tension (Po) of the individual chemically skinned or freeze-dried fibers representative of each fiber type. Following physiology, the relative percent content of MHC and MLC isoforms in these single fibers will also be correlated to Vo and Po to determine if these physiologic parameters are related to contractile protein expression as is the case in other human skeletal muscle. The long-term objectives of this work are to provide detailed, basic information regarding the exceedingly complex contractile protein expression in human jaw-closing muscle, the classification of specific fiber types distinct or similar to other skeletal muscle, and the main physiological properties of each fiber type. This information may serve as a basis from which dentistry may apply a more thorough understanding of jaw-closing muscle function to common clinical problems such as temporomandibular joint disorders, abnormal craniofacial growth and stability after orthognathic surgical procedures.

描述（改编自申请人的摘要）：哺乳动物骨骼 传统上，肌肉纤维被分为特定类型 肌原纤维 ATP 酶的表征和代谢 组织化学和最近的肌球蛋白免疫组织化学 重链 (MHC) 特异性抗体。人体骨骼肌含有 三种主要纤维类型：源自特定的 I、IIA 和 IIX（或 IIB） MHC 同工型。哺乳动物的下颌闭合肌纤维明显不同 与其他骨骼肌相比，体现出特殊性 他们的职能。人类灵长类动物的下颌闭合肌纤维 是最特殊的，表达发育和心脏 MHC， 其他成人骨骼中未发现的肌球蛋白轻链 (MLC) 亚型 肌肉，以及典型的成人骨骼亚型。 一个完整的 目前对人类咬肌肌球蛋白表达的描述 不完整，以及纤维类型分类方案，结合了两者 肌球蛋白含量与收缩功能有关，缺乏。利用人类 咬肌活检，这项研究的第一个具体目的是 开发基于下颌闭合肌肉的纤维类型分类方案 通过组织染色确定 MHC 和 MLC 鉴定： 肌原纤维 ATP 酶和代谢组织化学、免疫组织化学 使用 MHC 特异性抗体并使用探针进行原位杂交 由不同的 MHC 基因转录物发展而来。在全肌肉活检中 在单纤维中，MHC含量将通过甘油-SDS-来确定 通过 2-D 电泳检测 PAGE 和 MLC 含量。此外，电子 显微镜将用于评估相对异质性 肌球蛋白亚型在代表性纤维内的分布。 第二个 本研究的目的是确定卸载的最大速度 通过松弛测试确定的缩短率 (Vo) 和比张力 (Po) 单个化学结皮或冷冻干燥纤维 代表每种纤维类型。根据生理学，相对 这些单纤维中 MHC 和 MLC 同种型的百分比含量也将 与 Vo 和 Po 相关以确定这些生理参数是否 与收缩蛋白表达有关，就像其他情况一样 人体骨骼肌。这项工作的长期目标是 提供有关极其复杂的详细的基本信息 人类下颌闭合肌中的收缩蛋白表达 与其他纤维类型不同或相似的特定纤维类型的分类 骨骼肌，以及各纤维的主要生理特性 类型。该信息可以作为牙科可能的基础 更全面地了解下颌闭合肌肉的功能 常见的临床问题，例如颞下颌关节紊乱， 正颌手术后颅面生长和稳定性异常 程序。