Related Experiment Video
Updated: Jun 21, 2026
Use of a Hanging Weight System for Coronary Artery Occlusion in Mice
Published on: April 19, 2011
Comparison of the effects of different magnesium administration times on infarct size
Diego R Martínez Demaría1, Horacio E Cingolani, Susana M Mosca
1Fellow in Cardiology, Residencia Hospitalaria Universitaria del Hospital Italiano de La Plata, La Plata; and.
Background:
The protection of high magnesium on infarct size remains controversial.
Objective:
To examine the effects of magnesium administered before ischemia or early in reperfusion on infarct size in a rat model of global ischemia
Methods:
Isolated rat hearts were submitted to 40 min of normothermic global ischemia and 2 h of reperfusion. After 20 min of stabilization, four protocols were performed: ischemic control (IC) hearts; 15 mM of magnesium chloride administered 15 min before ischemia (MgI); 15 mM of magnesium chloride administered during the first 15 min of reperfusion (MgR); or 15 mM magnesium plus 5 mM calcium (Mg+Ca) before ischemia. Infarct size was measured by triphenyltetrazolium staining. Contractile function was assessed by left ventricular developed pressure and the maximal velocity of rise of left ventricular presssure.
Results:
The infarct size in IC hearts was 44+/-5%. In MgI and MgR hearts, the infarct diminished to 4.5+/-1.5% and 18+/-4%, respectively. In Mg+Ca hearts, the protection was also obtained (19+/-3%). Myocardial function also improved significantly by magnesium treatment. At the end of reperfusion, left ventricular developed pressure and maximal velocity of rise of left ventricular pressure values were 23+/-6% and 22+/-3% in MgI; and 10+/-3% and 9+/-2.6% in MgR versus 2+/-0.7% and 2.3+/-0.8% in IC hearts, respectively.
Conclusion:
The treatment with magnesium either before ischemia or early in reperfusion has an infarct size limiting effect in a model of global ischemia. This protective effect is partially due to its calcium antagonistic action.
