Recuperação funcional após traumatismo cranioencefálico: um modelo experimental

Abstract

Traumatic brain injury (TBI) is a neurotrauma with a complex pathophysiology caused by an external mechanical force. The damage from TBI can be divided into primary and secondary. The primary damage is related to mechanical collision of the brain and the secondary, related to neurochemical and immunoexcitotoxic processes caused by the temporal progression of the injury. Called the “silent epidemic”, it is the biggest cause of disability for young adults around the world. Animal models of TBI are used to mimic pathophysiological processes and allow the investigation of new therapies and interventions. The Weight-drop models allows the induction of TBI in rodents without previous surgical interventions, allowing a better understanding of the pathophysiological cascades of TBI. In addition, in this model, considered to be the closest to the human TBI, the monitoring of basic vital parameters can be used as an aid in the classification and prognosis related to TBI. In the present study, we propose a new weight-drop model apparatus to induce moderately severe closed-head TBI. We evaluated the effect of a 48.5g free-fall projectile from a height of 1.10 m in 8-week-old young adult rats. Control (sham), G1 (1h post-trauma), G2 (3 days post-trauma) and G3 (7 days post-trauma) groups were used. After the induction of TBI groups and the Sham group, had daily weight assessment, temperature within 1h post-TB and daily within the 7 days. Also, they underwent behavioral tests such as Open Field, to assess motor parameters and Novel Object Recognition test, to assess cognitive impairments. In addition, the prefrontal cortex, hippocampus and hypothalamus samples of the animals were used to assess levels of oxidative stress. Our results demonstrated that the TBI animals had less weight gain during the 7 days of evaluation, as well as significant fluctuations in body temperature. The TBI groups, also showed motor and cognitive deficits, especially on the 7th day after the injury. In addition, it showed higher levels of oxidative stress in the prefrontal cortex, hippocampus and hypothalamus compared to sham group. These findings suggest that the present model may be a possible candidate for translational studies.