ABSTRACT
BACKGOUND: This study was purposed to evaluate the effects of Mg2+ pretreatment on cerebral ischemic injury in cats. METHODS: Global cerebral ischemia was induced by ligation of both innominate arteries following ligation of inferior vena cava under lowered mean blood pressure for 20 minutes followed by 3 hrs of reperfusion. Ten cats were divided into 2 groups: Group 1 (n=5) is the control group, for group 2 (n=5) (Mg2+ group), the animals were pretreated with 90 mg/kg of Mg2+ intravenously before subjected to ischemia. RESULTS: Phosphocreatine/inorganic phosphate (Pcr/Pi) and pH decreased after ischemia and did not recovered during reperfusion. And there were no significant differences between the two groups. The ratios of lactate/N-acetyl aspartate (Lac/NAA) and lactate/creatine (Lac/Cr) increased after ischemia and not recovered during reperfusion. But the ratios were higher for the group 2 than the group 1 during reperfusion (p<0.05). For the Mg2+ group, blood pressure during reperfusion was lower than the control group. CONCLUSIONS: Mg2+ intravenous pretreatment had no protective effect on this global cerebral ischemia animal model. Even it deteriorated brain energy metabolism by lowering blood pressure.
