Experimental Diffuse Brain Injury in Rats-Comparative Study of Hypothermia and MgSO4

초록

Introduction: Given that diffuse brain injury(DBI) causes high mortality and that the management of DBI is very intricate, countless efforts have been taken to evaluated the pathophysiology of DBA both clinically and experimentally. With some promising results of these efforts, several new trials for the DBI treatment are being carried out. Method: The experiment was performed using hypothermia and MgSO4 experimental groups. For this experiment, 80 Sprague-Dawley rats were divided into four groups; a control group, a group treated with MgSO4, a group treated with hypothermia, and a group treated with both MgSO4 and hypothermia. In the hypothermic group, the rats were aintained at a rectal temperature of 32 degrees for an one hour after the injury and warmed back to their normothermic level over about 30 minutes. For The MgSO4 experimental group, the rats were treated with 750 umol/Kg of MgSO4 intramuscularly 30 minutes after the trauma. The group which had both treatments were kept hypothermic and given MgSO4. After 12 hours, 24 hours, one, and two weeks. Rats in each group were sacrificed and their apoptosis and axonal injury were evaluated. In the case of apoptosis use was made of terminal deoxynucleotidyl-transferase-mediated biotin dUTP nick end labelling(TUNEL) stain and axonal injury was evaluated with immunohistochemical stain for B-amyloid precursor protein(B-APP). Results: In the hypothermic and MgSO4 experiments, all treated groups had a significant reduction at each of the four time periods in apoptotic cells and damaged axonal density(which was marked by B-APP) in comparison with thew control group(p<0.001). However, the hypothermic groups(treated with or without MgSO4) showed a significant reduction in apoptotic cells than group treated with MgSO4 two weeks after trauma(p<0.001). However, the hypothermic group treated also with MgSO4 showed no significant reduction in apoptotic cells compared to the hypothermia only group(p>0.05). Immunohistochemical