Exogenous H2S protects H9c2 cardiac cells against high glucose-induced injury and inflammation by inhibiting the activation of the NF-κB and IL-1β pathways

摘要

Hyperglycemia has been reported to activate the nuclear factor?κB?(NF?κB) pathway. We have previously demonstrated that exogenous hydrogen sulfide?(H2S) protects cardiomyocytes against high glucose?(HG)?induced injury by inhibiting the activity of p38 mitogen?activated protein kinase?(MAPK), which can activate the NF?κB pathway and induce interleukin?(IL)?1β production. In the present study, we aimed to investigate the hypothesis that exogenous H2S protects cardiomyocytes against HG?induced injury and inflammation through the inhibition of the NF?κB/IL?1β pathway. H9c2 cardiac cells were treated with 35?mM glucose?(HG) for 24?h to establish a model of HG?induced damage. Our results demonstrated that treatment of the cells with 400?μM sodium hydrogen sulfide?(NaHS, a donor of H2S) or 100?μM pyrrolidine dithiocarbamate?(PDTC, an inhibitor of NF?κB) for 30?min prior to exposure to HG markedly attenuated the HG?induced increase in the expression levels of the phosphorylated?(p)?NF?κB p65 subunit. Notably, pre?treatment of the H9c2 cardiac cells with NaHS or PDTC significantly suppressed the HG?induced injury, including cytotoxicity, apoptosis, oxidative stress and mitochondrial insults, as evidenced by an increase in cell viability, as well as a decrease in the number of apoptotic cells, the expression of cleaved caspase?3, the generation of reactive oxygen species?(ROS) and the dissipation of mitochondrial membrane potential?(MMP). In addition, pre?treatment of the cells with NaHS or PDTC ameliorated the HG?induced inflammatory response, leading to a decrease in the levels of IL?1β, IL?6 and tumor necrosis factor?α?(TNF?α). Importantly, co?treatment of the H9c2 cells with 20?ng/ml IL?1 receptor antagonist?(IL?1Ra) and HG markedly reduced the HG?induced increase in p?NF?κB?p65 expression, cytoto-xicity, the number of apoptotic cells, as?well?as the production of TNF?α. In conclusion, the present study presents novel mechanistic evidence that exogenous H2S protects H9c2 cardiac cells against HG?induced inflammation and injury, including cytotoxicity, apoptosis, overproduction of ROS and the dissipation of MMP, by inhibiting the NF?κB/IL?1β pathway. We also provide new data indicating that the positive interaction between the NF?κB pathway and IL?1β is critical in HG?induced injury and inflammation in H9c2 cardiac cells.