Correlation between subacute sensorimotor deficits and brain water content after surgical brain injury in rats

Abstract

Brain edema is a major contributor to poor outcome and reduced quality of life after surgical brain injury (SBI). Although SBI pathophysiology is well-known, the correlation between cerebral edema and neurological deficits has not been thoroughly examined in the rat model of SBI. Thus, the purpose of this study was to determine the correlation between brain edema and deficits in standard sensorimotor neurobehavior tests for rats subjected to SBI. Sixty male Sprague-Dawley rats were subjected to either sham surgery or surgical brain injury via partial frontal lobectomy. All animals were tested for neurological deficits 24 post-SBI and fourteen were also tested 72 hours after surgery using seven common behavior tests: modified Garcia neuroscore (Neuroscore), beam walking, corner turn test, forelimb placement test, adhesive removal test, beam balance test, and foot fault test. After assessing the functional outcome, animals were euthanized for brain water content measurement. Surgical brain injury resulted in a significantly elevated frontal lobe brain water content 24 and 72 hours after surgery compared to that of sham animals. In all behavior tests, significance was observed between sham and SBI animals. However, a correlation between brain water content and functional outcome was observed for all tests except Neuroscore. The selection of behavior tests is critical to determine the effectiveness of therapeutics. Based on this study’s results, we recommend using beam walking, the corner turn test, the beam balance test, and the foot fault test since correlations with brain water content were observed at both 24 and 72 hours post-SBI.

Recombinant Slit2 attenuates neuroinflammation after surgical brain injury by inhibiting peripheral immune cell infiltration via Robo1-srGAP1 pathway in a rat model

“…However, there was no significant difference in neurological function after Slit2 siRNA knockdown compared to the SBI group. Given that Garcia test and beam balance test examine the overall gross sensorimotor deficits, it is possible that these tests were not sensitive enough to detect fine sensorimotor deficits which may result from the perisurgical site edema (Krafft et al, 2014, McBride et al, 2015). Additionally, these tests include parameters that evaluate function of the bilateral side and it is likely that the rats compensated for deficits using the uninjured side which may have reduced sensitivity of these tests (Krafft et al, 2014).…”

Modification of kynurenine pathway via inhibition of kynurenine hydroxylase attenuates surgical brain injury complications in a male rat model

“…The modified Garcia test consisted of evaluation of seven parameters for the SBI model (Garcia, Wagner, Liu, & Hu, ; McBride, Wang, Sherchan, Tang, & Zhang, ). These parameters included: (a) Spontaneous activity: animals were placed in a large cage and observations were made on the animal's level of activity for 5 min.…”

“…The test examined the animal's ability to walk on a beam (100cm x 2.25cm diameter) connected by two platforms at the ends. Each animal received a score ranging from 0 to 4 with higher scores indicating better performance (McBride et al, ; Zausinger, Hungerhuber, Baethmann, Reulen, & Schmid‐Elsaesser, ). The scoring was as follows: 5, animal reached platform within 25 s; 4, animal reached platform between 25 and 40 s; 3, animal moved halfway to a platform and stayed on the beam for at least 25 s; 2, animal moved less than halfway on the beam and stayed on the beam for at least 25 s; 1, animal did not move and stayed on the beam for 40 s; and 0, animal fell off the beam in less than 25 s.…”

Crotalus atrox venom preconditioning increases plasma fibrinogen and reduces perioperative hemorrhage in a rat model of surgical brain injury

“…The brain was removed and dissected into left and right hemispheres. Hematoma volume was quantified by spectrophotometric assay of brain hemoglobin content as described previously48. A standard curve was obtained by adding incremental volumes of homologous blood to perfused brain tissue of naïve animals.…”