Effect of Mg₂SO₄ usage on spinal cord ischemia-reperfusion injury: Electron microscopic and functional evaluation

Objectives: To evaluate the effects of intravenous magnesium sulfate (Mg₂SO₄) administration on ischemia-reperfusion injury of the spinal cord. Material and Methods: Sixteen rabbits were randomly assigned to the control (group I, 8 rabbits) and the study group (group II, 8 rabbits). The abdominal aorta was clamped for a period of 30 min followed by a reperfusion period of 60 min. The animals in group II received 0.25 ml/kg/h Mg₂SO₄ intra-venous infusion (15% Mg₂SO ₄) throughout this procedure. The animals were then observed for 24 h after which their neurological states were evaluated and tissue samples obtained from the spinal cord were examined with electron microscopy. Results: Aortic pressure distal to the cross-clamp during the occlusion period was 9 ± 3 mm Hg in group I and 19 ± 6 mm Hg in group II. All animals in group I were paraplegic at the end of the study. In group II the neurological outcome of 1 animal was poor while the other 7 animals were neurologically in a good condition. Electron microscopic examinations of the spinal cord tissues of group I revealed severe injury but the ultrastructure was well preserved in group II. Conclusions: Intravenous Mg₂SO₄ administration may have protective effects on the ischemia-reperfusion injury of the spinal cord. We propose that Mg₂SO₄ may be an additional protective pharmacological agent in thoracal and thoracoabdominal aortic surgery.