Laboratory of Histophysiology, Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Hyogo, Japan.
Department of Anatomy, Division of Histology and Cell Biology, Jichi Medical University, School of Medicine, Tochigi, Japan.
J Vet Med Sci. 2023 Feb 1;85(2):123-134. doi: 10.1292/jvms.22-0433. Epub 2022 Dec 13.
Our previous studies and others have revealed detailed characteristics of the mucosal nerve network in the small intestine, but much remains unknown about the corresponding network in the large intestine. We herein investigated regional differences in the expression of neurochemical markers, the nerve network structure, and the cells in contact with nerve fibers by histological analysis using both immunohistochemistry and serial block-face scanning electron microscopy (SBF-SEM). Immunohistochemistry revealed that immunopositive structures for protein gene product 9.5, vasoactive intestinal peptide (VIP), calretinin and vesicular acetylcholine transporter were more prevalent in the lamina propria of the ascending colon than the cecum and descending colon (DC). There was no significant difference in the frequency of most neurochemical markers between the cecum and DC, but the frequencies of VIP structures were higher in the cecum than in the DC. SBF-SEM analysis showed that the nerve network structure was more developed on the luminal side of the DC than the cecum. The cells that nerve fibers abundantly contacted were subepithelial and lamina propria fibroblast-like cells and macrophages. In addition, nerve fibers in the cecum were in more frequent contact with immune cells such as macrophages and plasma cells than nerve fibers in the DC. Thus, the present histological analysis suggested that the mucosal nerve network in the large intestine possessed both regional universality and various specificities, and revealed the intimate relationship between the nerve network and immune cells, especially in the cecum.
我们之前的研究和其他研究已经揭示了小肠黏膜神经网络的详细特征，但大肠相应网络的许多方面仍不清楚。我们通过免疫组织化学和连续块面扫描电子显微镜（SBF-SEM）的组织学分析，研究了神经化学标志物表达、神经网络结构和与神经纤维接触的细胞在大肠不同区域的差异。免疫组织化学显示，在升结肠的固有层中，蛋白基因产物 9.5、血管活性肠肽（VIP）、钙视网膜蛋白和囊泡乙酰胆碱转运体的免疫阳性结构比盲肠和降结肠更为普遍。大多数神经化学标志物在盲肠和降结肠之间的频率没有显著差异，但 VIP 结构的频率在盲肠中高于降结肠。SBF-SEM 分析显示，在降结肠的腔侧，神经网络结构比盲肠更为发达。神经纤维大量接触的细胞是黏膜下和固有层成纤维细胞样细胞和巨噬细胞。此外，与降结肠中的神经纤维相比，盲肠中的神经纤维与巨噬细胞和浆细胞等免疫细胞的接触更为频繁。因此，本组织学分析表明，大肠黏膜神经网络既具有区域性普遍性，又具有各种特异性，并揭示了神经网络与免疫细胞之间的密切关系，特别是在盲肠中。
