咬合创伤致牙髓血管及CGRP阳性神经的改变

Changes of pulp vessels and CGRP-immunoreactive fibres induced by occlusal trauma

目的:探讨咬合创伤对大鼠牙髓降钙素基因相关肽(CGRP)阳性纤维及牙髓血管的影响,和牙髓神经和血管反应间的关系。方法:HE和免疫组织化学染色方法,观察右下颌第一磨牙咬合创伤大鼠,右下牙槽神经干切断大鼠及空白对照大鼠的右下颌第一磨牙牙髓血管形态、CGRP阳性纤维末梢的形态变化。分析比较二者间的关系。结果:咬合创伤3-30天组,牙髓血管扩张程度和例数进行性增加。无细胞区CGRP-阳性纤维密度逐渐增加。相邻切片对比后显示扩张的血管和毛细血管的相应位置,CGRP-免疫阳性表达增强。牙髓炎症区内炎细胞浸润和血管扩张渗出处,CGRP-免疫阳性结构明显增多、表达增强。60-90天组,牙髓变性坏死例数增多,使牙髓血管扩张例数相对减少,扩张区域伴有CGRP-免疫阳性表达增强。咬合创伤并切断下牙槽神经干组,可见无细胞区有少量CGRP免疫阳性物质,呈淡染的颗粒状,短丝状。血管扩张不明显。1例标本牙髓血管明显扩张,相应区域CGRP阳性纤维束呈浓密的树枝状。结论:咬合创伤引起神经形态的改变及神经源性炎症,神经纤维和牙髓血管在分布上和变化上有一致性。

Objective： To investigate the. effect of occlusal trauma on the pulp CGRP-immunoreactice fibres and pulp blood vessels in rat, and observe the relation between pulp nerves and blood vessels. Methods： The morphology of CGRP- immunoreactive fibres and blood vessels in right first mandibular molar pulp tissue of occlusal trauma, inferior alveolar nerve （IAN） resection and control group in rat were compared using HE staining and Immunohistochemical staining. Results： In the group of occlusal trauma from 3 to 30 days, vasodilation in pulp progressively enhanced and the density of CGRP- positive fibres gradually increased in the cell free zone. CGRP-immunoreactive expression enhanced in the capillary area, and CGRP-immunoreactive expression increased in the region of inflammatory infiltration and vasodilation. In occlusal trauma 60-90 days group, because of the degeneration and necrosis of pulpal tissue, CGRP-immunoreactive expression gradually reduced in the cell free zone, but still without recovering to the level of control. Degenerative and necrotic range of pulp expanded, and vasodilative area were observed to shrank relatively. In IAN resection group, at 30 days of occlusal trauma, CGRP-immunoreactive fibres showed hypochromic granule and short filaments in the cell free zone. Vasodilation in pulp was not present. CGRP-immunoreactive fibre in one case bound in pulp chamber and appeared dense tree-like struc- ture; the pulp vasodilation was obvious in relevant area. Conclusions： Occlusal trauma could change the morphology of the nerve and cause the neurogenic inflammation. The change of pulp circulation following occlusal trauma was confirmed to consistent with the distribution and density of nerve fibers, which might be a mechanism of pulposis induced of occlusal trauma.