IMD protects H9c2 myocardial cells against the toxic injury induced by doxorubicin through suppressing the endoplasmic reticulum stress

WU Si-si; CHEN Hua-li; DING Yu; JIANG Wei

doi:10.3969/j.issn.1001-9448.2017.12.003

Abstract：Objective To study the pharmacologic actions and the underlying mechanisms of a cardiovascular active peptide, intermedin (IMD), against the cardiac injury induced by DOX exposure in DOX-treated H9c2 cells.Methods Cell damage model was established on H9c2 cells with DOX.Cells were challenged with different treatments and divided into the control group, Dox (2 μmol/L) group, IMD17-47 (1 μmol/L) group and 3 different dosages of IMD8-47 (10-8, 10-6 and 10-5mol/L) groups.CCK-8 method was used to detect cell viabilities;malondialdehyde (MDA) assay was used to determine the cellular oxidative stress levels;and western blot was used to evaluate the protein levels of the active caspase-3 fragment and the marker of endoplasmic reticulum stress, glucose-regulated protein 78 kD (GPR78).Furthermore, the mRNA expression levels of endogenous IMD and its receptors were detected by a real-time PCR method.Results Compared with control, DOX exposure significantly reduced cell viabilities, increased intracellular MDA contents, cleaved-caspase-3 and GPR78 levels.Compared with DOX group, supplementation of the IMD receptor antagonist IMD17-47 blocked the actions of DOX-induced endogenous IMD, and leaded to lower cell viability, higher intracellular MDA content, cleaved-caspase-3 and GPR78 levels;exogenous IMD supplementation promoted cell viabilities, reduced cellular MDA contents, apoptosis and endoplasmic reticulum stress levels in a concentration-dependent manner.In addition, DOX treatment significantly increased the mRNA expression of endogenous IMD and its receptors in H9c2 cells.Conclusion DOX exposure stirs the expression of endogenous IMD and its receptors in myocardial cells.Both endogenous IMD and exogenous IMD supplementation provide pharmacological protections against cardiac toxicity through DOX-upregulated IMD receptor systems, and effectively suppress DOX-induced oxidative stress and endoplasmic reticulum stress, thus promote myocardial cell survival and inhibit cell apoptosis.