Pan Feng, Mi Jing-Yi, Zhang Yan, Pan Xiao-Yun, Rui Yong-Jun
Department of Hand Surgery, Wuxi Number 9 People's Hospital Affiliated to Soochow University, Wuxi, 214062, Jiangsu, People's Republic of China.
J Muscle Res Cell Motil. 2016 Jun;37(3):95-100. doi: 10.1007/s10974-016-9450-8. Epub 2016 Jul 26.
The failure to accept reinnervation is considered to be one of the reasons for the poor motor functional recovery of intrinsic hand muscles (IHMs) after nerve injury. Rat could be a suitable model to be used in simulating motor function recovery of the IHMs after nerve injury as to the similarities in function and anatomy of the muscles between human and rat. However, few studies have reported the muscle fiber types composition and endplate morphologic characteristics of intrinsic forepaw muscles (IFMs) in the rat. In this study, the myosin heavy chain isoforms and acetylcholine receptors were stained by immunofluorescence to show the muscle fiber types composition and endplates on type-identified fibers of the lumbrical muscles (LMs), interosseus muscles (IMs), abductor digiti minimi (AM) and flexor pollicis brevis (FM) in rat forepaw. The majority of IFMs fibers were labeled positively for fast-switch fiber. However, the IMs were composed of only slow-switch fiber. With the exception of the IMs, the other IFMs had a part of hybrid fibers. Two-dimensional morphological characteristics of endplates on I and IIa muscle fiber had no significant differences among the IFMs. The LMs is the most suitable IFMs of rat to stimulate reinnervation of the IHMs after nerve injury. Gaining greater insight into the muscle fiber types composition and endplate morphology in the IFMs of rat may help understand the pathological and functional changes of IFMs in rat model stimulating reinnervation of IHMs after peripheral nerve injury.
无法接受再支配被认为是神经损伤后手部固有肌（IHMs）运动功能恢复不佳的原因之一。由于人与大鼠肌肉在功能和解剖结构上具有相似性，大鼠可能是用于模拟神经损伤后IHMs运动功能恢复的合适模型。然而，很少有研究报道大鼠前爪固有肌（IFMs）的肌纤维类型组成和终板形态特征。在本研究中，通过免疫荧光对肌球蛋白重链同工型和乙酰胆碱受体进行染色，以显示大鼠前爪蚓状肌（LMs）、骨间肌（IMs）、小指展肌（AM）和拇短屈肌（FM）中已鉴定类型纤维的肌纤维类型组成和终板。大多数IFMs纤维对快速转换纤维呈阳性标记。然而，IMs仅由慢速转换纤维组成。除IMs外，其他IFMs有一部分混合纤维。I型和IIa型肌纤维上终板的二维形态特征在各IFMs之间无显著差异。LMs是大鼠中最适合用于刺激神经损伤后IHMs再支配的IFMs。深入了解大鼠IFMs的肌纤维类型组成和终板形态可能有助于理解大鼠模型中IFMs在周围神经损伤后刺激IHMs再支配时的病理和功能变化。
