2D <em>vs</em> 3D morphological analysis of dorsal root ganglia in health and painful neuropathy

Abstract

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.

MRI-based radiomics features uncover the micro-change of dorsal root ganglia lesion for patients with post-herpetic neuralgia

“…The dorsal root ganglia (DRG) comprise diverse populations of sensory and satellite glial cells with varying neurochemical profiles. DRG stress can induce notable changes in cell size (swelling/atrophy) and in distinct subcellular structures (e.g., mitochondria, endoplasmic reticulum, and nucleus) of neurons and/or satellite glial cells ( 27 ). Consequently, leveraging the DRG’s heterogeneity and coarse texture via radiomics could facilitate the investigation of postherpetic neuralgia (PHN) at the cellular and molecular levels.…”

Engineering a multicompartment in vitro model for dorsal root ganglia phenotypic assessment

“…39,[62][63][64][65][66] However, in 3D culture, cells are embedded within a matrix where the mechanical properties are tunable by modifying the composition. 61,[67][68][69][70] Specifically, increasing matrix stiffness of a 3D hydrogel has been correlated with decreased neurite length of sensory neurons from neonatal rat superior cervical ganglia 71 ; therefore, it is important to use a matrix with mechanical properties that mimic native neuronal tissue. It is important to note that both dissociated and 3D explant DRGs have been cultured in 3D matrices in previous literature, as indicated in Table 1.…”

Label‐Free Visualization and Morphological Profiling of Neuronal Differentiation and Axonal Degeneration through Quantitative Phase Imaging

“…These approaches encompass investigations into neuronal morphology, electrical responses, and the expression of molecular markers. [ 7–8 ] Compromised sensory functions have been notably associated with morphological changes, including distal fiber loss, demyelination, and axonal degeneration. [ 9 ] In this regard, neurite length measurement stands out as one of the most commonly used assays for in vitro axon degeneration investigations, due to its simplicity.…”