舌黏膜结构特点及其与药物吸收关系

Morphological characteristics of the lingual mucosa and its relationship with drug absorption

目的：通过对大鼠舌黏膜和黏膜下层结构特点的观察，为多肽类药物跨舌黏膜吸收的途径和能力，提供结构基础方面的依据。方法：选用成年SD大鼠，进行H—E染色与酶组织化学显色、扫描以及透射电镜观察和摄像。将酶组织化学显色的组织切片再次应用扫描电镜，进行二次电子图像（SEI）和背散射电子图像（BED的观察和摄像。结果：酶组织化学显色与H—E染色切片的结构相似，但可明显区分管腔结构。扫描电镜显示，舌腹侧面与背侧面分界清楚，形态差异较大。酶染组织切片的扫描电镜（SEI及BEI）观察舌腹侧黏膜下层和肌层内，淋巴管较多、管径较大。透射电镜观察表明，舌内毛细血管的管壁较厚，而舌内毛细淋巴管仅由一层内皮细胞构成，管腔较大而且不规则，内皮外无周细胞，存在开放性间隙，管壁外缺乏基膜。结论：大鼠舌腹侧与舌背侧的黏膜形态存在较大的差异，可能与功能有关；舌的毛细淋巴管的管径和通透性，远远大于毛细血管，舌下含服多肽类药物的吸收途径，可能更易通过淋巴系统，然后进入血液循环。

Objective： To explore the morphological characteristics of lingual mucosa and submucosa of rat, and to provide therefore structural basis for the route and ability of polypeptide drugs administrated by lingual mucosa. Methods： The morphological characteristics of the mucous membrane of tonugue in rats were observed by HE stain, enzyme histochemistry, scanning electron microscope （SEM） and transmission electron microscope （TEM）. The secondary electrom images （SEI） and backscattered electron images （BED were obtained. Results： The morphological structures exhibited both in HE stain and enzyme histochemistry stain were similar and the lumina could be distinguished. The results from SEM showed that the dorsum and base of tongue were distincted due to their different appearance. The SEI and BEI showed that there were more lymphatic vessels with bigger diameters within the submucosa and muscular layer. The figures from TEM showed that the walls of capillaries within the tongue were thicker, whereas the walls of the lymphatic capillaries were formed by single layer of endothelial cells. The lymphatic capillaries had bigger lumia and no pericytes were found. The basement membrane was undetectable outside of wall of lymphatic capillaries, whereas the open gaps were found. Conclusion： Mophological differences between the dorsum and base of tongue might relate to the different function. The advantage in permeability of lymphatic capillaries may lead to a preferring absorption of drug to blood circulation.