1 Instituto de Biología, Laboratorio de Microscopía Electrónica, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
2 Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
J Dent Res. 2018 Mar;97(3):347-355. doi: 10.1177/0022034517733967. Epub 2017 Oct 3.
Schwann cells are glial cells that support axonal development, maintenance, defense, and regeneration in the peripheral nervous system. There is limited knowledge regarding the organization, plasticity, and aging of Schwann cells within the dental pulp in adult permanent teeth. The present study sought to relate changes in the pattern of Schwann cell phenotypes between young and old adult teeth with neuronal, immune, and vascular components of the dental pulp. Schwann cells are shown to form a prominent glial network at the dentin-pulp interface, consisting of nonmyelinating and myelinating phenotypes, forming a multicellular neuroimmune interface in association with nerve fibers and dendritic cells. Schwann cell phenotypes are recognized by the expression of S100, glial fibrillary acidic protein (GFAP), myelin basic protein (MBP), Sox10, GAP43, and p75NTR markers. In young adult teeth, a dense population of nonmyelinating Schwann cells projects processes in close association with sensory nerve terminals through the odontoblast layer, reaching the adjacent predentin/dentin domain. While GAP43 and p75NTR are highly expressed in nonmyelinating Schwann cells from young adult teeth, the presence of these markers declines significantly in old adult teeth. Myelinated axons, identified by MBP expression, are mainly present at the Raschkow plexus and within nerve bundles in the dental pulp, but their density is significantly reduced in old adult versus young adult teeth. These data reveal age-related changes within the glial network of the dental pulp, in association with a reduction of coronal dental pulp innervation in old adult versus young adult teeth. The prominence of Schwann cells as a cellular component at the dentin-pulp interface supports the notion that their association with sensory nerve terminals and immune system components forms part of an integrated multicellular barrier for defense against pathogens and dentin repair.
许旺细胞是神经胶质细胞，在周围神经系统中支持轴突的发育、维持、防御和再生。关于成年恒牙牙髓内许旺细胞的组织、可塑性和衰老，人们知之甚少。本研究旨在探讨牙髓内许旺细胞表型的变化与牙髓内神经元、免疫和血管成分之间的关系。结果表明，许旺细胞在牙本质-牙髓界面形成一个突出的神经胶质网络，由无髓鞘和有髓鞘表型组成，与神经纤维和树突状细胞形成一个多细胞神经免疫界面。许旺细胞表型通过 S100、胶质纤维酸性蛋白（GFAP）、髓鞘碱性蛋白（MBP）、Sox10、GAP43 和 p75NTR 标志物的表达来识别。在年轻恒牙中，大量无髓鞘许旺细胞的突起与感觉神经末梢紧密相关，通过成牙本质细胞层到达相邻的前期牙本质/牙本质区域。虽然 GAP43 和 p75NTR 在年轻恒牙的无髓鞘许旺细胞中高度表达，但在老年恒牙中这些标志物的表达显著下降。通过 MBP 表达鉴定的有髓轴突主要存在于牙髓的 Raschkow 丛和神经束中，但在老年恒牙中其密度明显低于年轻恒牙。这些数据揭示了牙髓内神经胶质网络的年龄相关性变化，与老年恒牙与年轻恒牙相比，冠部牙髓神经支配的减少有关。许旺细胞作为牙本质-牙髓界面的细胞成分的突出地位支持这样一种观点，即它们与感觉神经末梢和免疫系统成分的关联构成了一个整合的多细胞防御屏障的一部分，以抵御病原体和牙本质修复。
