Protective Effects of Magnesium Against Ischaemia–reperfusion Injury Through Inhibition of P‐selectin in Rats

Abstract

1. The leucocyte-mediated inflammatory response plays a pivotal role in ischaemia-reperfusion injury. P-Selectin and CD11b are important mediators for the recruitment of leucocytes into the endothelium. However, the time-course of changes in P-selectin and CD11b expression during reperfusion is not defined. Magnesium has been shown to have a protective role in reperfusion injury, but the mechanism of its action is not yet clear. 2. In the present study, 90 male Sprague-Dawley rats were randomized into three groups, namely a sham-operated group, an IR group (subjected to 45 min of coronary occlusion followed by reperfusion for up to 6 h) and an MgSO(4)-treated group, which received an infusion of MgSO(4) starting 30 min before occlusion and continuing until the onset of reperfusion. The expression of P-selectin on platelets and CD11b on leucocytes, endothelial P-selectin on cardiac microvessels and P-selectin mRNA in myocardial tissue were measured by flow cytometry, immunohistochemistry and reverse transcription-polymerase chain reaction, respectively, at different time points during reperfusion. The degree of myocardial necrosis and arrhythmia was assessed. 3. The present study shows that P-selectin expression on platelets and cardiac microvessels, P-selectin mRNA in myocardial tissue and CD11b expression on leucocytes in the IR group were significantly upregulated compared with the sham-operated group in a time-dependent manner during reperfusion. Treatment with MgSO(4) attenuated the upregulation of P-selectin expression, in addition to inhibiting myocardial necrosis and arrhythmia, but had no effect on CD11b expression on leucocytes. 4. These results suggest that the expression of P-selectin and CD11b is upregulated after reperfusion and magnesium pretreatment plays a cardioprotective role in ischaemia-reperfusion injury, possibly by inhibiting the upregulation of P-selectin expression.

Magnesium—Essentials for Anesthesiologists

“…176 Infarct size could also be limited when magnesium was administered within 15-45 min after reperfusion of the coronaries. 168,169,177…”

Comparison of trace element levels after cardiopulmonary bypass between cyanotic and acyanotic patients

“…[26][27][28] An animal study demonstrated the cardioprotective role of magnesium pre-treatment in ischaemia re-perfusion injury. 29 Marinque et al 30 showed that the incidence of postoperative junctional ectopic tachycardia can be reduced by magnesium sulphate administration during the re-warming phase of cardiopulmonary bypass. In adult cardiac surgery, the role of magnesium in postoperative atrial fibrillation in unclear or controversial.…”

Magnesium Lowers the Incidence of Postoperative Junctional Ectopic Tachycardia in Congenital Heart Surgical Patients: Is There a Relationship to Surgical Procedure Complexity?

“…Using a Langendorff rat model of hypoxia-re-oxygenation injury, Sato et al demonstrated that high intra-myocardial levels of magnesium prevented intracellular calcium overload, but also facilitated the opening of mitochondrial KATP channels [20, 23], preserving resting membrane potential. In another rat model study, magnesium pretreatment played a cardio-protective role in ischemia-reperfusion injury, possibly by inhibiting the upregulation of P-selectin expression [24]. …”