大鼠食管肌间神经元nNOS与calbindin的共存及其与衰老关系的研究(英文)

本实验通过观察一氧化氮合酶(nNOS)与细胞内钙结合蛋白(calbindin, CB)共存情况,旨在研究大鼠食管内NO类神经元的神经化学特性并试图寻找出引起食管NO类神经元在衰老过程中丢失的可能原因。取自不同年龄组及种系(Wistar和S-D)大鼠的食管组织,制成肌间神经丛铺片,经nNOS与CB免疫组化双重染色后在荧光显微镜下观察。结果显示,nNOS与CB的免疫阳性反应物均见于大鼠食管肌间神经元胞体内。根据二者共存情况,大鼠食管内nNOS免疫阳性神经元可分为两大亚类:nNOS+/CB+及nNOS+/CB-。而且我们首次发现在大鼠食管腹腔段含有大量nNOS+/CB+神经元,约占NO类神经元总体的30% ~40%,与食管其它部位相比有显著差异(P<0.001)。另外,大鼠食管腹腔段绝大多数CB免疫阳性神经元同时也为nNOS免疫阳性(约占95% ~100%)。上述特征均见于本实验所观察的所有不同年龄及不同种系的大鼠食管内。在大鼠衰老过程中,nNOS+/CB+神经元的相对百分比的变化具有种系特异性。线形回归实验分析表明:年轻SD大鼠食管内nNOS+/CB+神经元的百分比含量与衰老过程中NO类神经元丢失数量的百分比之间存在显著负相关性(correlation coefficient 0.99;P<0.05)。结果提示在S-D大鼠衰老过程中其食管内NO类神经元的丢失可能与其细胞内钙结合蛋白含量的变化有关。但nNOS/CB共存神经元在分布上有明显差异的生物学意义尚有待于进一步研究。

CO-LOCALISATION OF nNOS AND CALBINDIN IN THE MYENTERIC NEURONES OF RAT ESOPHAGUS WITH A SPECIFIC REGIONAL DISTRIBUTION PATTERN AND THEIR RELATIONSHIP WITH AGING

In order to characterize the neurochemical features of nitrergic myenteric neurons in the rat esophagus and to disclose some possible cause of nitrergic neuronal cell loss in the rat esophagus during aging, whole-mount preparations from different esophageal segments of different age- and strain-groups were studied by double immunohistochemistry of neuronal nitric oxide synthase (nNOS) and calbindin (CB). We found for the first time co-localization of nNOS and CB in myenteric neuronal bodies with a specific distribution pattern along the entire length of rat esophagus: significantly higher percentage of nNOS/CB immunoreactive (ir) myenteric neurons (ca 30%-40%) were found in the abdominal segment in comparison with the other segments of the organ (P<0.001). Nitrergic myenteric neurons in the rat esophagus could be subdivided at least into two groups: nNOS~+/CB~+ and nNOS~+/CB~-. Moreover, the majority of CB-ir myenteric neurons,especially in the abdominal esophagus expressed nNOS-ir (ca 95%-100%). All these features were persisted in all age and strain groups of rats studied. The relative percentages of the nNOS-/CB-ir neurons among the total nitrergic population varied strain-dependently during aging. Regression analysis yielded a significant negative correlation between the percentage of nNOS-/CB-ir neurons found in the young Sprague-Dawley rats and percentage of nitrergic neuronal loss during aging (correlation coefficient 0.99; P< 0.05). However, the functional significance of the regional differences in nNOS-/CB-ir neurons along the rat esophagus remains to be elucidated.