人眼外肌肌腱连接处的细胞骨架蛋白。

PURPOSE: The purpose of this study was to investigate the cytoskeletal composition of myotendinous junctions (MTJs) in the human extraocular muscles (EOMs). Desmin and other major cytoskeletal proteins are enriched at the MTJs of ordinary myofibers, where they are proposed to be of particular importance for force transmission and required to maintain myofiber integrity. METHODS: EOM and limb muscle samples were analyzed with immunohistochemistry using antibodies against the intermediate filament proteins desmin, nestin, keratin 19, vimentin, and different myosin heavy chain (MyHC) isoforms. MTJs were identified by labeling with antibodies against laminin or tenascin. RESULTS: In contrast to MTJs in lumbrical muscle where desmin, nestin, and keratin 19 were always present, approximately one-third of the MTJs in the EOMs lacked either desmin and/or nestin, and all MTJs lacked keratin 19. Approximately 6% of the MTJs in the EOMs lacked all of these key cytoskeletal proteins. CONCLUSIONS: The cytoskeletal protein composition of MTJs in human EOMs differed significantly from that of MTJs in limb muscles. These differences in cytoskeletal protein composition may indicate particular adaptation to meet the functional requirements of the EOMs.

目的：本研究旨在探讨人类眼外肌（EOM）肌-腱连接（MTJ）的细胞骨架组成。结蛋白和其他主要的细胞骨架蛋白在普通肌纤维的 MTJ 中丰富，据推测它们对于力的传递特别重要，并且需要维持肌纤维的完整性。

方法：使用针对中间丝蛋白结蛋白、巢蛋白、角蛋白 19、波形蛋白和不同肌球蛋白重链（MyHC）同工型的抗体，对 EOM 和肢体肌肉样本进行免疫组织化学分析。通过针对层粘连蛋白或腱糖蛋白的抗体进行标记来识别 MTJ。

结果：与在蚓状肌中始终存在结蛋白、巢蛋白和角蛋白 19 的 MTJ 不同，EOM 中约三分之一的 MTJ 缺乏结蛋白和/或巢蛋白，并且所有 MTJ 均缺乏角蛋白 19。EOM 中约 6%的 MTJ 缺乏所有这些关键的细胞骨架蛋白。

结论：人 EOM 的 MTJ 细胞骨架蛋白组成与肢体肌肉的 MTJ 明显不同。这些细胞骨架蛋白组成的差异可能表明对满足 EOM 功能需求的特殊适应。