人牙髓淋巴管相关标志物的表达和超微结构分析

目的：探讨健康牙髓中是否存在淋巴管。方法：选择因正畸拔除的牙30颗，取出牙髓，以健康牙龈组织做阳性对照，利用淋巴管特异性标志物D2-40和LYVE-1以及血管标志物CD31和CD34进行免疫组织化学染色，Western印迹法检测D2-40的表达，透射电镜进行超微结构分析。结果：健康牙髓组织中，管腔结构的内皮细胞均显示CD31和(或)CD34阳性，D2-40除成牙本质细胞弱阳性表达外，管腔结构均阴性表达。Western印迹法检测显示，用胶原酶去除牙髓成牙本质细胞后，D2-40所对应的分子量40 kDa的条带消失。牙髓管腔结构的内皮细胞电镜检测显示出血管而不是淋巴管的特征，即由单层内皮细胞组成，外有周细胞围绕，基底膜完整。结论：在人正常牙髓组织中可能不存在淋巴管，淋巴系统是否参与牙髓炎症的引流过程尚有待进一步研究。

Specific markers and ultrastructure of lymphatic vessel in healthy human dental pulp

PURPOSE: To explore the existence of lymphatic vessels in healthy human dental pulp. METHODS: Thirty healthy human dental pulps were obtained from non-carious premolars removed for orthodontic reasons. Immunohistochemistry was performed using the antibodies specific for lymphatic endothelium such as D2-40 and LYVE-1, and for vascular endothelial cell such as CD31 and CD34. The expression of D2-40 was detected by Western blotting and ultrastructure was examined by transmission electron microscopy. RESULTS: In healthy human dental pulps, we failed to detect any reactivity for the lymphatic markers D2-40 and LYVE-1 in the observed vessels. These vessels were positive stained by blood endothelial markers CD34 and CD31. Odontoblasts were weakly stained with D2-40. Western blotting performed on collagenase-treated human dental pulps did not show a band at 40 kDa, corresponding to the molecular weight of the lymphatic marker D2-40. Transmission electron microscopy indicated that vessels in dental pulp consisted of endothelial monolayer surrounded by pericytes and complete basement membrane, which were typical ultrastructural characteristics of blood vessels rather than lymphatic vessel. CONCLUSIONS: Human dental pulp does not contain true lymphatic vessels under healthy conditions. Whether lymphatic system is involved in dental pulp interstitial fluid circulation during inflammation deserved further study.