Cardioprotective effect of Shenxiong glucose injection on acute myocardial infarction in rats via reduction in myocardial intracellular calcium ion overload

Purpose: To explore the cardioprotective effects and potential mechanisms of Shenxiong Glucose Injection (SGI) in rat acute myocardial infarction (AMI).
Methods: AMI model was created by ligating left anterior descending coronary artery. After 7 days’ consecutive intravenous administration of SGI, serum samples were used to conduct biochemical analysis while hearts were excised and processed for infraction size, enzyme activity, histopathology and qPCR studies. Intracellular Ca²⁺ {(Ca²⁺)i} overload in H9c2 cells was measured by laser scanning confocal microscope (LSCM).
Results: In AMI rats, pretreatment with SGI significantly ameliorated myocardial histopathologic damage. It exerted cardioprotective effect by decreasing myocardial infarct size, electrocardiogram (ECG) ST segment elevation, and CK, cTnI, BNP levels in serum. In addition, SGI significantly decreased calmodulin (CaM) and calmodulin-dependent protein kinase II (CaMK II) mRNA expression, but increased Ca²⁺-Mg²⁺-ATPase and Na+-K+-ATPase activities in myocardium. In doxorubicin (DOX)-induced H9c2 cells injury model, SGI reversed (Ca²⁺)i overload to protect cells.
Conclusion: The results demonstrate SGI exerts cardioprotective effect by decreasing myocardial infarct size, restoring ST segment and reversing (Ca²⁺)i overload. It suggests that SGI may be a new clinical candidate to treat myocardial infarction.

Keywords
Shenxiong glucose injection; Tanshinol; Ligustrazine; Myocardial infarction; Intracellular Ca²⁺ overload; Calmodulin; Calmodulin-dependent protein kinase II