Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, Monza (MB).
Department of Veterinary Sciences, University of Turin, Grugliasco (TO).
Eur J Histochem. 2021 Oct 19;65(s1):3276. doi: 10.4081/ejh.2021.3276.
Dorsal root ganglia (DRGs) are clusters of sensory neurons that transmit the sensory information from the periphery to the central nervous system, and satellite glial cells (SGCs), their supporting trophic cells. Sensory neurons are pseudounipolar neurons with a heterogeneous neurochemistry reflecting their functional features. DRGs, not protected by the blood brain barrier, are vulnerable to stress and damage of different origin (i.e., toxic, mechanical, metabolic, genetic) that can involve sensory neurons, SGCs or, considering their intimate intercommunication, both cell populations. DRG damage, primary or secondary to nerve damage, produces a sensory peripheral neuropathy, characterized by neurophysiological abnormalities, numbness, paraesthesia and dysesthesia, tingling and burning sensations and neuropathic pain. DRG stress can be morphologically detected by light and electron microscope analysis with alterations in cell size (swelling/atrophy) and in different sub-cellular compartments (i.e., mitochondria, endoplasmic reticulum, and nucleus) of neurons and/or SGCs. In addition, neurochemical changes can be used to portray abnormalities of neurons and SGC. Conventional immunostaining, i.e., immunohistochemical detection of specific molecules in tissue slices can be employed to detect, localize and quantify particular markers of damage in neurons (i.e., nuclear expression ATF3) or SGCs (i.e., increased expression of GFAP), markers of apoptosis (i.e., caspases), markers of mitochondrial suffering and oxidative stress (i.e., 8-OHdG), markers of tissue inflammation (i.e., CD68 for macrophage infiltration), etc. However classical (2D) methods of immunostaining disrupt the overall organization of the DRG, thus resulting in the loss of some crucial information. Whole-mount (3D) methods have been recently developed to investigate DRG morphology and neurochemistry without tissue slicing, giving the opportunity to study the intimate relationship between SGCs and sensory neurons in health and disease. Here, we aim to compare classical (2D) vs whole-mount (3D) approaches to highlight "pros" and "cons" of the two methodologies when analysing neuropathy-induced alterations in DRGs.
背根神经节 (DRG) 是感觉神经元的集群，它们将来自外周的感觉信息传递到中枢神经系统，卫星神经胶质细胞 (SGC) 是其支持营养细胞。感觉神经元是一种假单极神经元，具有异质的神经化学特性，反映了它们的功能特征。DRG 不受血脑屏障的保护，容易受到不同来源的应激和损伤（即毒性、机械性、代谢性、遗传性）的影响，这些损伤可能涉及感觉神经元、SGC 或考虑到它们之间的密切相互交流，这两种细胞群。DRG 损伤，无论是原发性还是继发性的神经损伤，都会导致感觉周围神经病变，其特征是神经生理学异常、麻木、感觉异常和感觉异常、刺痛和烧灼感以及神经性疼痛。DRG 应激可以通过光镜和电子显微镜分析来检测，其特征是神经元和/或 SGC 细胞大小（肿胀/萎缩）和不同亚细胞区室（即线粒体、内质网和细胞核）的改变。此外，神经化学变化可用于描绘神经元和 SGC 的异常。常规免疫染色，即组织切片中特定分子的免疫组织化学检测，可用于检测、定位和定量神经元（即核表达 ATF3）或 SGC（即 GFAP 表达增加）、细胞凋亡标志物（即半胱天冬酶）、线粒体损伤和氧化应激标志物（即 8-OHdG）、组织炎症标志物（即巨噬细胞浸润的 CD68）等特定损伤标志物。然而，经典的（2D）免疫染色方法破坏了 DRG 的整体组织，因此会丢失一些关键信息。全（3D）方法最近已经开发出来，用于研究 DRG 形态和神经化学，而无需组织切片，从而有机会在健康和疾病状态下研究 SGC 和感觉神经元之间的密切关系。在这里，我们旨在比较经典（2D）与全（3D）方法，以突出两种方法在分析 DRG 神经病变诱导改变时的“利弊”。
