Magnesium Sulfate Does Not Protect Spinal Cord Against Ischemic Injury

Abstract

ABSTRACTObjective: We tested various doses of MgSO4 to investigate the effect of Mg on a spinal cord ischemia. Methods: Rats were treated with either MgSO4 (30, 100, or 300 mg/kg; group Mglow, group Mgmedium, group Mghigh, respectively, n = 10 for each) or saline (control group; n = 10) before ischemia. Spinal cord ischemia was induced using a balloon-tipped catheter placed on proximal descending aorta. During surgery, hemodynamic variables were recorded before ischemia, during aortic occlusion and after reperfusion. Neurologic function was assessed using the motor deficit index (MDI; 0 = normal, 6 = complete paralysis) until seven days after reperfusion, and histologic examination of spinal cord was performed. Results: After reperfusion, the mean arterial pressure in the group Mghigh was significantly lower than other groups. Compared to the control group, the groups Mglow and Mgmedium did not show any difference in MDI and the group Mghigh showed significantly higher MDI. The number of normal motor neurons was similar among other groups except the group Mghigh had a significantly fewer normal motor neurons. Conclusions: Intravenous MgSO4 with low or medium dose (30, or 100 mg/kg) did not improve neurological injury following spinal cord ischemia. Furthermore, higher dose of MgSO4 (300 mg/kg) resulted in hemodynamic instability and aggravated neurologic outcome.