[Protective effect of ophiopogonin D against isoproterenol-induced cardiomyocyte injury and targets].

This study aims to unveil the effect of ophiopogonin D(OPD) on isoproterenol(ISO)-induced apoptosis of rat cardiomyocytes and the possible targets, which is expected to provide clues for further research on the myocardial protection of ophiopogonins. Cell count kit-8(CCK-8) assay was used to detect viability of cells treated with OPD and ISO, Western blot to examine the effect of OPD and ISO on the expression of endoplasmic reticulum stress-related Bip, Bax, Perk, ATF4, caspase-12, and CHOP, flow cytometry to determine cell apoptosis rate, and Hoechst 33258 and Tunel staining to observe cell apoptosis and morphological changes. In addition, the probe for calcium ion-specific detection was employed to investigate calcium ion release from the endoplasmic reticulum, and OPD-bond epoxy-activated agarose solid-phase microspheres were prepared and used as affinity matrix to capture OPD-binding target proteins in H9 c2 cell lysate. For the target proteins of OPD identified by high-resolution mass spectrometry, the related signal pathways were enriched and the potential targets of OPD against cardiomyocyte injury were discussed. The experimental result showed that 10 μmol·L~(-1) ISO can significantly induce the expression of endoplasmic reticulum stress-related proteins and promote cell apoptosis. Different concentration of OPD can prevent the damage of myocardial cells caused by ISO. According to mass spectrometry results, 19 proteins, including Fam129 a and Pdia6, were involved in multiple signaling pathways such as the unfolded protein reaction bound by the ERN1 sensor, tricarboxylic acid cycle, and Nrf2 signal transduction pathway. The above results indicate that OPD protects cardiomyocytes by regulating multiple signaling pathways of target proteins and affecting cell cycle progression.