Efeito da Estimulação Transcraniana por Corrente Contínua (ETCC) sobre parâmetros comportamentais, morfológicos, e bioquímicos em modelo experimental de dor induzida por inflamação crônica

Abstract

The chronic pain process is, in the most part of the times, related to factors that lead to changes in cognition, appetite, as well as chronic stress, insomnia, increased anxiety, irritability manifestations. Therefore, it results in restrictions on the execution of professional and social activities. The imbalance of the nociceptive system triggers the release of inflammatory mediators and modulators activation of glial cells. Molecules such as brain-derived neurotrophic factor (BDNF), protein kinases, cytokines, neurotransmitters and pre and / or post-inflammatory, which actively participate in the mechanism of chronic inflammatory pain. Studies show that non-pharmacological methods, non-invasive and that act on the central nervous system through electrical stimulation are excellent tools in the treatment of diseases such as chronic pain. The transcranial direct-current stimulation (tDCS) is a modulation method capable of promoting the markers involved in the signaling of inflammatory processes. Therefore, the aim of this study was to evaluate the effect of tDCS on behavioral, morphological and biochemical parameters in rats subjected to a chronic inflammation model. This experimental study used 54 Wistar rats, which were divided into two groups (control group and CFA group). Thus, the control group received saline injection and CFA group was submitted to chronic inflammation induced by Freund's adjuvant, and later to 7 days were treated with tDCS. The behavioral parameters such as the von Frey and the hot plate were evaluated immediately, 24 hours and 8 days after treatment, whereas the size of the paw edema and weight of the animals only once and 8 days of treatment. The morphological features were assessed by histological techniques and biochemical assays occurred through commercial kits analyzed by ELISA. hus, the von Frey test, all animals receiving CFA decreased the nociceptive threshold. However, the animals of group CFA tDCS showed an increase of nociceptive threshold immediately after last session of tDCS, lasting from 24 hours to 8 days of the last tDCS session. BDNF levels measured in the prefrontal cortex and hippocampus showed no significant difference between the groups, but in serum levels was observed significant difference in group CFA Sham- ETTC and CFA tDCS compared to tDCS control group.This study aimed to better understand the involvement of tDCS in signaling chronic inflammatory pain.