Sweroside Effectively Protects Against Ischemia/Reperfusion Injury by Regulating Excitation-contraction Coupling / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo explore the effect of sweroside on the protection of cardiac systolic/diastolic function during ischemia/reperfusion （I/R） injury. MethodTwenty-four healthy male SD rats were randomly divided into control group， model group， 10 μmol·L-1 sweroside group and 1 μmol·L-1 digoxin group. The I/R injury was modeled by Langendorff and ligation of the left anterior descending coronary artery. The infarct size in each group was measured by 2，3，5-triphenyltetrazolium chloride （TTC） staining and hemodynamic parameters such as left ventricular diastolic pressure （LVDP）， left ventricular end-diastolic pressure （LVEDP）， left ventricular end-systolic pressure （LVESP）， maximum rate of rising of left ventricular pressure （+dp/dtmax） and maximum rate of decreasing of left ventricular pressure （-dp/dtmax） of rat isolated heart were detected by Powerlab. In addition， neonatal rat cardiomyocytes （NRCMs） were isolated and randomly divided into control group， model group， 1 μmol·L-1 sweroside group and 10 μmol·L-1 sweroside group. Hypoxia/reoxygenation （H/R） injury model was established. Cardiac systolic function and calcium transients were examined by multi-functional cell imaging analyzer and laser confocal microscope. Furthermore， real-time polymerase chain reaction（Real-time PCR） was used to verify the mRNA expression of excitation-contraction coupling genes such as L-type calcium channel （Cacnb2）， cytochrome c oxidase subunit 6A2 （Cox6a2）， troponin （Tnnc1， Tnni3， Tnnt2）， actin （Actc1）， and myosin （Myh6， Myl2， Myl4） according to the results of previous transcriptome sequencing and literature investigation. Differentially expressed genes were subjected to cluster analysis. ResultCompared with the conditions in the control group， increased cardiac infarction size （P<0.01） and LVEDP （P<0.01） and decreased LVDP （P<0.01） and LVESP （P<0.05） were observed in the model group， with +dp/dtmax of increasing trend while -dp/dtmax decreasing. Moreover， the cell viability， heart rate and contraction amplitude of NRCMs was reduced （P<0.01）， while the contraction duration， time to peak and relaxation time was elevated （P<0.01） in the model group. Interestingly， sweroside could reverse these indicators （P<0.05）. In addition， the expression of Cacnb2， Cox6a2， Tnnc1， Tnni3， Tnnt2， Actc1， and Myh6， Myl2， and Myl4 was down-regulated in the model group （P<0.05， P<0.01）， but sweroside could up-regulate the expression of the above genes （P<0.05）. ConclusionSweroside effectively regulated Ca2+ level in NRCMs， enhanced cardiac systolic function， and protected against H/R injury by regulating excitation-contraction coupling.