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: 2391232
• 负责人: JAMES J SCIOTE
• 金额: $ 9.61万
• 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/2391232
• 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(改编自申请者摘要)：哺乳动物骨骼 传统上，肌肉纤维被分类为特定的类型 它们的肌原纤维ATPase的特性和代谢 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。人类骨骼肌含有 三种主要纤维类型：I、IIA和IIX(或IIB)源自特定 MHC亚型。哺乳动物的闭口肌纤维明显不同 与其他骨骼肌相比，体现了专门性 它们的功能。人类灵长类令人瞠目结舌的肌肉纤维 是最特殊的，表达发育和心脏MHC和 肌球蛋白轻链(MLC)亚型在其他成人骨骼中未发现 肌肉，以及典型的成人骨骼异构体。一个完整的 目前对肌球蛋白在人咬肌中表达的描述 不完整，以及纤维类型分类方案，两者都包含在内 肌球蛋白含量和收缩功能缺乏。使用人类 咬肌活组织检查，本研究的第一个具体目的是 提出一种基于神经网络的闭口肌纤维类型分类方案 通过组织染色确定MHC和MLC的鉴定： 肌原纤维ATPase和代谢组织化学、免疫组织化学 MHC特异性抗体与探针的原位杂交 由不同的MHC基因转录本发展而来。在全肌肉活检中 而在单纤维中，MHC的含量将通过甘油-十二烷基硫酸钠确定。 PAGE和双向电泳法测定MLC含量。此外，电子 显微镜将被用来评估相对的异质性 肌球蛋白亚型在典型纤维中的分布。第二 本研究的目的是确定最大卸载速度。 松弛试验所确定的缩短率(Vo)和比张力 (PO)单独的化学剥皮或冷冻干燥纤维 代表每种纤维类型。在生理学之后，相对的 这些单一纤维中MHC和MLC异构体的百分比含量也将 与Vo和Po相关，以确定这些生理参数是否 与收缩蛋白的表达有关，在其他 人类骨骼肌。这项工作的长期目标是 提供有关极其复杂的 收缩蛋白在人类闭合肌中的表达 对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 打字。这些信息可以作为牙科医生的基础 应用更透彻的闭口肌功能了解 常见的临床问题，如颞下颌关节紊乱病， 正颌外科术后颅面发育异常及稳定性研究 程序。