Sprouting of bladder afferents after spinal cord injury: the role of growth inhibitory proteins at the lumbosacral spinal cord

Event Abstract Back to Event Sprouting of bladder afferents after spinal cord injury: the role of growth inhibitory proteins at the lumbosacral spinal cord Sílvia S. Chambel1, Raquel Oliveira1, Martin Schwab2 and Célia D. Cruz1* 1 Faculty of Medicine, University of Porto, Portugal 2 University of Zurich, Switzerland Spinal cord injury (SCI) leads to neurogenic detrusor overactivity (NDO), reflecting abnormal lumbosacral extension of central processes of bladder afferents. Mechanisms regulating this abnormal sprouting are still unresolved but may involve changes in expression of inhibitory cues that block axonal growth, including Nogo-A and Phosphacan. It is unclear if these proteins are regulated in the lumbosacral cord after thoracic injury and if bladder afferents adjust growth accordingly. Adult female rats were divided into three groups (n=8/group). The spinal cord was left intact in one group. Two groups underwent SCI at T8/T9 spinal segments and recovered for 7 or 28 days. Seven or 28 days post-injury (7 and 28 dpi), animals underwent 1-hour cystometry under urethane anesthesia, followed by tissue collection. Lumbosacral cords (L5-S1) were processed for Western Blotting and Immunohistochemistry to evaluate GAP43, Phosphacan and Nogo-A expression levels. Control animals presented normal bladder activity while bladder reflex contractions were abolished at 7 dpi in SCI rats (p≤0.0001 vs control). At 28 dpi, NDO was evident in SCI animals, with increased frequency and amplitude of bladder contractions (p≤0.0001 vs 7 dpi animals). Lumbosacral expression of Nogo- A and Phosphacan increased 7 dpi (p≤0.05 versus spinal intact) but significantly reduced at 28 dpi (Phosphacan; p≤0.05 vs 7 dpi animals). A time-dependent increase in GAP43 expression was found. Nogo-A expression in the dorsolateral funiculus was stronger at 7 dpi than in control animals. In controls, Phosphacan was expressed in the superficial dorsal horn, dorsolateral and ventral funiculus and some motoneurons. At 7dpi, staining intensity increased. In both cases, expression returned to baseline levels at 28 dpi. GAP43 was present in the superficial dorsal horn, dorsal commissure, corticospinal tract and dorsolateral funiculus in control animals, increasing at 7 and 28 dpi. We found absence of GAP43 in Phosphacan and Nogo-A positive spinal areas. This study demonstrates that changes in repulsive cues expression are not restricted to the injury but also occur at the lumbosacral cord, indicating the presence of a widespread event likely impacting recovery and NDO emergence. Ongoing studies aim to evaluate whether bladder afferents recognize centrally expressed growth-repellent cues. Figure 1 Keywords: spinal cord injury, Bladder, repulsive cues, cystometry, Urinary incontience Conference: XVI Meeting of the Portuguese Society for Neuroscience (SPN2019), Lisboa, Portugal, 30 May - 1 Jun, 2019. Presentation Type: Poster presentation Topic: Cellular and Molecular Neurosciences Citation: Chambel SS, Oliveira R, Schwab M and Cruz CD (2019). Sprouting of bladder afferents after spinal cord injury: the role of growth inhibitory proteins at the lumbosacral spinal cord. Front. Cell. Neurosci. Conference Abstract: XVI Meeting of the Portuguese Society for Neuroscience (SPN2019). doi: 10.3389/conf.fncel.2019.01.00038 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 16 Apr 2019; Published Online: 27 Sep 2019. * Correspondence: Prof. Célia D Cruz, Faculty of Medicine, University of Porto, Porto, Portugal, ccruz@med.up.pt Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Sílvia S Chambel Raquel Oliveira Martin Schwab Célia D Cruz Google Sílvia S Chambel Raquel Oliveira Martin Schwab Célia D Cruz Google Scholar Sílvia S Chambel Raquel Oliveira Martin Schwab Célia D Cruz PubMed Sílvia S Chambel Raquel Oliveira Martin Schwab Célia D Cruz Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.