异搏定对Ca^2＋增加牙髓神经纤维诱发放电的抑制作用

目的：了解钙离子及钙通道在牙齿激发痛传导中的作用。方法：应用牙齿激发痛动物模型观察低浓度ＣａＣｌ２及钙通道阻滞剂异搏定对牙髓神经诱发放电的影响。结果：０．８５％ＣａＣｌ２溶液可增加气流刺激诱发牙髓神经放电数目。异搏定可抑制气流刺激诱发的牙髓神经放电，并抑制ＣａＣｌ２增加牙髓神经诱发放电的作用，两种抑制作用与异搏定的浓度有关。结论：０．８５％ＣａＣｌ２增加诱发放电的作用与Ｃａ２＋通道有关     

牙髓神经痛过敏的外周机制

８０年代，随着神经肽的发现，人们对牙髓肽能神经纤维（特别是Ｃ纤维）的认识不断深化。本文就牙髓内肽能神经纤维（特别是Ｃ纤维）的走行，分布，受刺激后的动态变化以及其生理特性与牙髓神经痛过敏的联系进行了综述，并提出了牙髓神经痛过敏产生的可能外周机制。     

牙髓神经痛过敏的外周机制

80年代,随着神经肢的发现,人们对牙髓肽能神经纤维(特别是C纤维)的认识不断深化。本文就牙髓内肽能神经纤维(特别是C纤维)的走行、分布、受刺激后的动态变化以及其生理特性与牙髓神经痛过敏的联系进行了综述,并提出了牙髓神经痛过敏产生的可能外周机制。     

牙髓慢性炎症中P物质阳性神经纤维的变化

目的：观察Ｐ物质阳性（ＳＰ－ＩＲ）神经纤维在正常牙髓中的分布,及其在慢性炎症过程中的变化,探讨ＳＰ与牙髓炎症的关系。方法：大鼠牙髓炎模型和免疫组织化学技术。结果：ＳＰ－ＩＲ神经纤维广泛分布于整个牙髓中,少量纤维进入牙本质小管;炎症早期ＳＰ－ＩＲ神经纤维数量增多、染色加重;炎症晚期,冠髓大量ＳＰ－ＩＲ神经纤维围绕于牙髓脓肿周围,根髓纤维发生出芽现象。结论：ＳＰ可能参与了牙髓炎症、修复过程,并可能与牙髓炎性痛过敏的发生有关。     

牙髓炎症中降钙素基因相关肽阳性神经纤维的变化

本研究的目的在于探讨牙髓炎症及修复过程的分子生物学机理。在大鼠磨牙制备近髓窝洞，封入新鲜龋坏组织，建立了大鼠牙髓炎模型。用免疫组织化学方法观察正常牙髓及炎症４天、８天、１４天牙髓降钙素基因相关肽（ＣＧＲＰ）阳性神经纤维的变化。结果表明，ＣＧＲＰ阳性神经纤维广泛存在于正常牙髓中，大量阳性纤维进入牙本质小管；炎症４天组的牙髓中及进入牙本质小管内的阳性神经纤维均明显增多；炎症８天组冠髓部分坏死，阳性神经纤维包绕坏死区周围，根髓阳性神经纤维显著增多并可见大量“出芽”（ｓｐｒｏｕｔｉｎｇ）；炎症１４天组牙髓已大部分坏死，尖周膜腔阳性神经纤维聚集。结果提示，ＣＧＲＰ可能参与了牙髓炎症及其修复过程。     

人牙乳头细胞分化过程中胞内Ca^2＋浓度变化和1，25（OH）2D3对Ca^2＋影响

目的：探讨人牙乳头细胞不同分化阶段和1,25（OH）2D3作用下细胞内Ca^2 的变化。方法：体外培养人牙乳头细胞,利用激光共聚焦显微镜观察细胞内Ca^2 浓度的变化。结果：具有某些成牙本质细胞表型的细胞（21d)胞内Ca^2 浓度比无分化表型的细胞（14d)高约2倍;1,25（OH）2D3使21d组细胞胞内Ca^2 明显升高,而14d组则无明显变化。结论：人牙乳头细胞在分化过程中胞内Ca^2 浓度上调;1,25（OH）2D3能提高牙乳头细胞静息内Ca^2 水平以达新的Ca^2 稳态,促进牙乳头细胞分化。     

牙髓神经纤维的特点和牙痛的外周机制

牙髓内的神经纤维主要有Aδ纤维和C纤维,它们的自由神经纤维末梢构成牙髓的痛觉感受器。牙髓神经活动的记录有牙本质记录和单一神经纤维记录两种方式。由于两类神经纤维组织结构、发育、分布不同,它们的传导速度、感受方式、耐受性、介导疼痛性质以及对内、外源性刺激的反应性也有所不同。本文还对一些药物对牙髓神经活动的影响,神经电生理研究与临床牙痛的相关性作一简要综述。     

EphA7在炎症状态下人牙髓组织中的表达和意义

目的:探讨Eph A7基因在牙髓的炎症反应和牙源性疼痛中的作用及意义。方法:收集健康牙髓、具有疼痛症状的牙髓炎牙髓和无疼痛症状的牙髓炎牙髓各18例,分别采用免疫组化染色和Western印迹法检测Eph A7蛋白在不同状态牙髓组织中的表达水平。结果:免疫组化染色显示:Eph A7在健康牙髓中仅阳性表达于血管内皮细胞和成牙本质细胞;而在炎症牙髓中,Eph A7的表达显著升高,除阳性表达于上述细胞外,同时还阳性表达于成纤维细胞、炎症细胞以及神经纤维组织中。Western印迹法检测结果显示:与健康牙髓相比,牙髓炎牙髓中Eph A7蛋白的表达水平显著增高(P<0.05),具有疼痛症状的牙髓中Eph A7蛋白的表达水平显著高于无疼痛症状的牙髓(P<0.05)。结论:Eph A7基因可能是反映牙髓组织炎症活动和疼痛状态的一个标记物。     

正常与炎症牙髓中降钙素基因相关肽免疫反应神经纤维的研究

目的观察人正常与炎症牙髓中降钙素基因相关肽免疫反应神经纤维（CGRP－IRF）的分布，为深入探讨神经系统如何参与牙髓的各种生理，病理改变的调节作用提供新的资料。方法采用ABC免疫组化法观察人正常牙髓中CGRP－IRF的分布及龋源性炎症牙髓中CGRP－IRF的改变。结果牙髓中CGRP－IRF为许多串珠状棕褐色点状连成的线条，含明显的膨体。正常牙髓中，CGRP－IRF多沿血管走行并分布在血管周围，一些单根CGRP－IRF远离血管，主要分布在造牙本质细胞下神经丛。髓角处，偶尔可见CGRP-IRF突入造牙本质细胞层。炎症牙髓中，在病损下方和血管周围CGRP－IRF明显增多。结论CGRP－IRF广泛分布于人牙髓中，在牙髓炎症中起重要作用。     

人牙髓干细胞来源外泌体促进周围神经损伤修复的实验研究

目的:研究人牙髓干细胞(human dental pulp stem cells,hDPSCs)来源外泌体对周围神经损伤修复的作用.方法:将36只成年SD大鼠随机分为2组,实验组为坐骨神经损伤后hDPSCs来源外泌体注射组,对照组为坐骨神经损伤后PBS注射组.分别于损伤后第3、7、14天观察大鼠的行为学改变,取材后进行...     

牙髓干细胞在周围神经损伤修复中的研究进展

周围神经损伤(peripheral nerves injury,PNI)是口腔临床常见病,极易造成患者功能丧失和美观异常,牙髓干细胞(dental pulp stem cells,DPSCs)结合组织工程在PNI修复中的应用是目前研究热点.DPSCs具有来源丰富、提取简单、免疫原性低以及体外增殖率高等优点,其可分化成雪...     

Inflammatory nerve responses in the dental pulp

Tooth pulp has a dense innervation and a rich vascular supply to maintain homeostasis and to preserve the integrity of the tissue. Function, trauma, and antigenic challenges make teeth and supporting tissues susceptible to tissue injury and inflammation, partially due to the lack of collateral blood and nerve supply and to their low compliance. This review focuses on dental nerve functions and adaptive changes in the pulpal nerve supply following inflammation and peripheral injury. Overviews of dental innervation and its development and of the peptidergic innervation of oral tissues are presented, followed by a discussion of peripheral and central changes after local insults to teeth and peripheral nerve injuries. The functional implications of these adaptive changes are considered.
Received 13 February 2009; accepted 3 September 2009.     

Freeze-fracture electron microscopy of non-myelinated nerve fibres in the human dental pulp

Freeze-fracture replicas from the subodontoblast region gave a good three-dimensional comprehension of the structure of non-myelinated nerve fibres. Each Schwann cell ensheathed 1-15 axons with a mean diameter of 0.4 micron (0.1-1.2 micron). Many axons were not entirely ensheathed but were exposed to the extracellular space to various degrees. Tightening membrane specializations were not found in the mesaxons. The Schwann-cell plasmalemma exhibited caveolae with necks surrounded by evenly-sized intramembranous particles, typical of endocytosis. The nuclear envelope of Schwann cells showed a few typical pores and perinuclear cisterna. In tangential fractures, the axolemma displayed intramembranous particles evenly distributed over the axolemmal fracture planes. There was a marked difference in particle density between the P (600-650/micron2) and E (150-200/micron2) faces.     

Lymphangiogenesis in human dental pulp

AIM: To investigate the impact of inflammation on lymphangiogenesis in human dental pulp. METHODOLOGY: Eleven samples of dental pulp without inflammation and 11 dental pulps with moderate to intense mononuclear cell inflammatory infiltrate associated with dentine caries were selected. The streptavidin-biotin complex stain was used to detect CD31, vascular endothelial growth factor receptor-3 (VEGFR-3) and alpha-smooth muscle actin. The number of lymphatic vessels was obtained by counting the number of vessels positive for CD31 and VEGFR-3 and negative for alpha-smooth muscle actin. RESULTS: The results demonstrated that the mean number (+/-SD) of vessels positive for CD31 and VEGFR-3 (lymphatic vessels) in the group with inflammation (6.09 +/- 1.81) was statistically higher (P = 0.0123) than the mean number in the group without inflammation (3.73 +/- 2.20). CONCLUSION: Increased co-immunostaining of CD31 and VEGF-3 in vessels associated with human dental pulp inflammation occurred, which suggests lymphangiogenesis.     

Expression of ecto-ATPase NTPDase2 in human dental pulp

Dental pulpal nerve fibers express ionotropic adenosine triphosphate (ATP) receptors, suggesting that ATP signaling participates in the process of dental nociception. In this study, we investigated if the principal enzymes responsible for extracellular ATP hydrolysis, namely, nucleoside triphosphate diphosphohydrolases (NTPDases), are present in human dental pulp. Immunohistochemical and immunofluorescence experiments showed that NTPDase2 was predominantly expressed in pulpal nerve bundles, Raschkow's nerve plexus, and in the odontoblast layer. NTPDase2 was expressed in pulpal Schwann cells, with processes accompanying the nerve fibers and projecting into the odontoblast layer. Odontoblasts expressed the gap junction protein, connexin43, which can form transmembrane hemichannels for ATP release. NTPDase2 was localized close to connexin43 within the odontoblast layer. These findings provide evidence for the existence of an apparatus for ATP release and degradation in human dental pulp, consistent with the involvement of ATP signaling in the process of dentin sensitivity and dental pain.