Les effets du fentanyl sur la douleur et la motricité suite à une hémorragie intracérébrale induite chez le rat
The pain associated with traumatic brain injury is linked with the central nervous system sensitization and chronic cephalalgia when pain is not treated. However, analgesics in human patient must be done with caution since they are associated with cognitive and motor deficits. The present study aims to assess the efficiency of fentanyl to treat pain and evaluate motor behaviors on a rat model of intracerebral hemorrhage (IH).   Twenty-one male Sprague-Dawley rats underwent a stereotaxic surgery to produce a collagenase-induced IH with an injection of 2 µL of colagenase (0.5 UI) in the right caudoputamen nucleus. The control group (n=6) received saline subcutaneously (SC), and experimental groups received either 5 (n=6), 10 (n=6), or 20 (n=3) µg/kg of fentanyl SC, 2h following surgery and on the 2 subsequent days. The rat grimace scale, a neurological examination, balance beam test and rotarod test were performed for 5 consecutive days postoperatively to evaluate pain and motor performance. At the end of the experimentation, the animals were euthanized, the brains were collected and evaluated to determine hematoma volume, the number of reactive astrocytes and necrotic neurons.  When compared to controls, the grimace scale has showed that 5 µg/kg fentanyl significantly alleviated pain on day 2 only (p<0.01) and that 10 µg/kg alleviated pain on days 1 (p<0.01), 2 (p<0.001), and 3 (p<0.01). For the rotarod test, only the 10 µg/kg group showed significant decreases in performance on days 5 (p<0.05) and 6 (p<0.02). The neurologic exam was not significantly different between groups, but only the hopping test showed a poor recuperation for the 5 and 10 µg/kg fentanyl group when compared to saline (p<0.01). During brains exams, no differences were found between groups for the results of the 3 parameters.  Fentanyl, at a dose of 10 µg/kg SC, has provided a substantial analgesia following a collagenase-induced intracerebral hemorrhage in rats; however it can alter motor performance following analgesic treatments.
Céphalalgie Histopathologie Analgesia Cephalalgia Grimace scale Histopathology Neurological exam Rats