Magnesium Sulfate Does Not Protect Spinal Cord Against Ischemic Injury

ABSTRACT

Objective: 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 Mg_low, group Mg_medium, group Mg_high, 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 Mg_high was significantly lower than other groups. Compared to the control group, the groups Mg_low and Mg_medium did not show any difference in MDI and the group Mg_high showed significantly higher MDI. The number of normal motor neurons was similar among other groups except the group Mg_high 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.

Keywords: :

• magnesium
• spinal cord ischemia
• thoracoabdominal aortic surgery
• hypotension

ACKNOWLEDGMENTS

This study was supported by grant number 11-2009-028 from Seoul National University Bundang Hospital research fund.

Declaration of Interest: The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.