神经肌肉接头在肠神经元发育异常病变肠段中的分布

Distribution of neuromuscular junctions in the bowel affected by mal development of intestinal innervation

目的应用两种神经肌肉接头的重要标记物———突触导素（ＳＹ）和神经细胞粘附分子（ＮＣＡＭ），对肠神经元发育异常症神经肌肉接头分布模式进行免疫组化的研究。方法分别取３０例先天性无神经节细胞症（ＨＤ）、３例肠神经节发育不良（ＮＩＤ）、２例肠神经节细胞减少症（ＨＹＰＧ）及１例神经节细胞未发育（ＩＭＧ）的病变肠壁全层作为病变组，取其正常的结肠壁全层作为对照组，采用免疫组化的方法对这两组肠壁的ＳＹ及ＮＣＡＭ分布方式进行光镜检查。结果正常组粘膜下神经丛和肌间神经丛有大量ＳＹ和少量ＮＣＡＭ染色的神经纤维，粘膜肌层、环肌和纵肌层有丰富的突触。ＨＤ病人组粘膜肌层、环肌和纵肌层ＳＹ染色的神经纤维及突触数量在狭窄段则明显稀少，ＮＣＡＭ染色的神经纤维数量明显增多；３例ＮＩＤ中，１例的粘膜肌层、环肌和纵肌层ＳＹ染色神经纤维数量减少明显，１例纵肌层和１例粘膜肌层无ＳＹ染色活性；在神经节细胞减少症组的肌间丛和肌层中只有少数神经肌肉接头。结论神经肌肉接头在肠神经元发育异常症中呈异常分布可能是肠神经发育异常症重要的发病机制，并可能是此类疾病肠运动障碍的原因之一。

Objective By using two important neuromuscular junction markers synaptophysin(SY) and neural cell adhesion molecule (NCAM) to investigate immunohistochemically the innervation pattern in maldlelopment of intestinal innervation. Methods Full thickness bowel specimens were obtained from the affected and normal intestinal segments of 30 patients with aganglionosis, 3 with NID, 2 with hypoganglionosis(HYPG), and 1 immature ganglia(IMG). Using immunohischemistry for light microscopy, we compared the pattern of the distribution of SY and NCAM in bowel of HD, NID, HYPG and IMG with that from normal controls. Results In normal bowel, SY immunoreactivity was abundant and NCAM immunoreactivity was sparse in the muscularis mucosae, circular and longitudinal muscle layers. In HD, there were sparse SY positive synapses within the circular and longitudinal muscle layers in the aganglionodsis sengment. However, of the speicmens from NID, there was absence of SY in muscularis muconsae, circular and longitudinal muscle layers in one; no immunoreactivity in the longitudinal muscle layers in another and no immunoreactivity in the muscularis mucosae in the other. In HYPG, these were a few neuromuscular junctions in the myenteric plexuses and muscle layers.Conclusion Abnormal distribution of neuromuscular junctions in the mal developed intestinal innervation may explain the bowel dysmotility seen in these patients.