Study of the effect of photobiomodulation in a model of comorbidity between post-traumatic stress and chronic neuropathic pain in an environment threatened by snakes

• Grant number: 22/12293-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2022
• End date: November 30, 2023
• Field of knowledge: Health Sciences - Medicine - Psychiatry
• Principal Investigator: Norberto Cysne Coimbra
• Grantee: Matheus Mazo Caffeu
• Host Institution: Instituto de Neurociências e Comportamento (INEC). Ribeirão Preto , SP, Brazil

Abstract

Post-traumatic stress disorder (PTSD) is considered by the Diagnostic and Statistical Manual of Mental Disorders as a disorder related to trauma and stressors caused by the experience of a traumatic event where, after such an event, there is an involuntary recall of it, triggering intense fear responses. In humans, there is a relationship between PTSD and chronic pain, in which PTSD potentially facilitates the onset of chronic pain. It is also known that patients with chronic pain are more likely to develop PTSD when exposed to a traumatic event. Recently, a new experimental model of PTSD associated with chronic neuropathic pain was proposed in the literature, based on the repeated exposure of laboratory animals to snakes and their exuvia as a way to study some behavioural reactions related to both unconditioned and conditioned fear. In this experimental model, the laboratory animal (prey) is confronted with a snake (a potential predator) and its exuvia and, subsequently, re-exposed to the aversive context with the exuvia (Mendes-Gomes et al., 2020). There is promising evidence from studies with photobiomodulation, mainly considering its brain effects. Therefore, the present work aims the submission of Rattus norvegicus with chronic neuropathic pain (caused by a chronic constriction injury of the ischiadicus nervus) to a prey versus predator paradigm, to trigger behavioural responses similar to those manifested in patients diagnosed with PTSD in comorbid with chronic pain. Subsequently, the potential anxiolytic and panicolytic-like effect of photobiomodulation procedure in a 10-day subchronic treatment will be analysed in each rodent.