Effect of Cannabidiol Treatment on Chronic Pain and Comorbidities Associated with Fibromyalgia

• Grant number: 24/05935-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2024
• End date: July 31, 2025
• Field of knowledge: Health Sciences - Nursing - Psychiatric Nursing
• Principal Investigator: Priscila Medeiros de Freitas
• Grantee: Victor Mathews Ribeiro Battisti
• Host Institution: Escola de Enfermagem de Ribeirão Preto (EERP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Chronic Pain (CP) is associated with high levels of disability. During CP, central sensitization phenomena are observed, with neuronal hyperexcitability of the somatosensory system to harmful or non-harmful agents. Fibromyalgia (FM) is a syndrome mainly characterized by musculoskeletal CP in multiple anatomical points. According to the IASP, FM is classified as a generalized primary CP. FM is correlated with CNS (cortical and spinal) sensitization. This triggers modifications in the neural mechanisms for processing and regulating pain, which can amplify pain or reduce its inhibition in individuals with the syndrome. These changes are not limited to a single region and can expand to other brain areas related to the processing of different functions, potentially explaining in a cortical way the presence of some comorbidities associated with FM (e.g. depression and memory impairment). Cannabidiol (CBD) has also been widely studied as an alternative in the management of CP and FM comorbidities. Thus, the objective of the present project will be to study the neuromolecular and psychopharmacological bases of FM through CBD treatment on CP pain, anxiety, depression, and memory impairments associated with FM. Initially, the animals will have their nociceptive thresholds assessed (von Frey, acetone, hotplate, and facial expression) weight and body temperature assessed. FM will be induced by administration of reserpine in mice [1 ml/kg (SC) once a day for 3 consecutive days]. On the fourth day, treatment with CBD (0.3, 1, and 3mg/kg) will begin up to 21 days after the last administration of reserpine. At the end of treatment, the animals will be evaluated in nociceptive and behavioral tests (object recognition test, Y-maze to evaluate mnemonic cognitive impairments) and by the elevated plus maze and open field tests (used to assess anxiety) and suspension test. of the tail and sucrose spray (used to evaluate predictive responses for depression) after 21 days of FM induction and treatment with CBD. The day after the end of all experiments, perfusion will be carried out to remove the brains, and subsequent neuromolecular studies.