Priscila Medeiros1,2,3, Ieda Regina Dos Santos2, Ivair Matias Júnior4, Enza Palazzo5, José Aparecido da Silva2,6,7, Hélio Rubens Machado1,4, Sérgio Henrique Ferreira1,8, Sabatino Maione5,9, Norberto Cysne Coimbra1,2,3, Renato Leonardo de Freitas1,2,6,8. 1. Laboratory of Neurosciences of Pain & Emotions and Neuroelectrophysiology Multi-User Centre, Department of Surgery and Anatomy, Ribeirão Preto Medical School of the University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil. 2. Laboratory of Neuroanatomy and Neuropsychobiology, Department of Pharmacology, Ribeirão Preto Medical School of the University of São Paulo (FMRP-USP), Ribeirão Preto, São Paulo, Brazil. 3. Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil. 4. Laboratory of Pediatric Surgery, Department of Surgery and Anatomy, Ribeirão Preto Medical School of the University of São Paulo, Ribeirão Preto, São Paulo, Brazil. 5. Division of Pharmacology, Department of Experimental Medicine, University of Campania "L. Vanvitelli," Naples, Italy. 6. Department of Psychology, Ribeirão Preto School of Philosophy, Sciences and Literature of the University of São Paulo, Ribeirão Preto, São Paulo, Brazil. 7. Psychology Department, Federal University of Juiz de Fora (UFJF-MG), Juiz de Fora, Minas Gerais, Brazil. 8. Biomedical Sciences Institute, Federal University of Alfenas (UNIFAL-MG), Str. Gabriel Monteiro da Silva, Alfenas, Minas Gerais, Brazil. 9. IRCCS Neuromed, 86077, Pozzilli-Caserta, Italy.
Abstract
BACKGROUND: Chronic constriction injury (CCI) is a model of neuropathic pain induced by four loose ligatures around the sciatic nerve. This work aimed to investigate the sensory, affective, cognitive, and motor changes induced by an adaptation of the CCI model by applying a single ligature around the sciatic nerve. METHODS: Mechanical allodynia was measured from day 1 to day 28 postsurgery by the von Frey test. The beam walking test (BWT) was conducted weekly until 28 days after surgery. Anxiety- and depression-like behaviors, and cognitive performance were assessed through the open field (OF), forced swimming (FS), and novel object recognition (NOR) tests, respectively, 21 days after surgery. RESULTS: The two CCI models, both Bennett and Xie's model (four ligatures of the sciatic nerve) and a modification of it (one ligature), induced mechanical allodynia, increased immobility in the FS, and reduced recognition index in the NOR. The exploratory behavior and time spent in the central part of the arena decreased, while the defensive behavior increased in the OF. The animals subjected to the two CCI models showed motor alterations in the BWT; however, autotomy was observed only in the group with four ligatures and not in the group with a single ligature. CONCLUSIONS: Overall these results demonstrate that our adapted CCI model, using a single ligature around the sciatic nerve, induces sensory, affective, cognitive, and motor alterations comparable to the CCI model with four ligatures without generating autotomy. This adaptation to the CCI model may therefore represent an appropriate and more easily performed model for inducing neuropathic pain and study underlying mechanisms and effective treatments.
BACKGROUND:Chronic constriction injury (CCI) is a model of neuropathic pain induced by four loose ligatures around the sciatic nerve. This work aimed to investigate the sensory, affective, cognitive, and motor changes induced by an adaptation of the CCI model by applying a single ligature around the sciatic nerve. METHODS:Mechanical allodynia was measured from day 1 to day 28 postsurgery by the von Frey test. The beam walking test (BWT) was conducted weekly until 28 days after surgery. Anxiety- and depression-like behaviors, and cognitive performance were assessed through the open field (OF), forced swimming (FS), and novel object recognition (NOR) tests, respectively, 21 days after surgery. RESULTS: The two CCI models, both Bennett and Xie's model (four ligatures of the sciatic nerve) and a modification of it (one ligature), induced mechanical allodynia, increased immobility in the FS, and reduced recognition index in the NOR. The exploratory behavior and time spent in the central part of the arena decreased, while the defensive behavior increased in the OF. The animals subjected to the two CCI models showed motor alterations in the BWT; however, autotomy was observed only in the group with four ligatures and not in the group with a single ligature. CONCLUSIONS: Overall these results demonstrate that our adapted CCI model, using a single ligature around the sciatic nerve, induces sensory, affective, cognitive, and motor alterations comparable to the CCI model with four ligatures without generating autotomy. This adaptation to the CCI model may therefore represent an appropriate and more easily performed model for inducing neuropathic pain and study underlying mechanisms and effective treatments.
Authors: Geiza Fernanda Antunes; Ana Carolina Pinheiro Campos; Danielle Varin de Assis; Flavia Venetucci Gouveia; Midiã Dias de Jesus Seno; Rosana Lima Pagano; Raquel Chacon Ruiz Martinez Journal: PLoS One Date: 2022-07-12 Impact factor: 3.752