Dexmedetomidine attenuates hypoxia/reoxygenation-induced cardiomyocyte injury in association with ADRA2A/ADRA2B and Notch1/Hes1 modulation.

Abstract

This study evaluated whether dexmedetomidine (Dex) attenuates hypoxia/reoxygenation (H/R)-induced injury in H9c2 cells and examined concurrent changes in adrenergic receptor candidates, Notch receptor 1 (Notch1), and hairy and enhancer of split-1 (Hes1) expression to develop a hypothesis-generating model of Dex-associated protection. H9c2 cells underwent 12 h of hypoxia followed by 4 h of reoxygenation. Cell viability, myocardial injury markers, oxidative stress, inflammatory cytokines, apoptosis, candidate-gene expression, and NOTCH1 and HES1 protein abundance were assessed. Notch1 overexpression was used to test the functional relevance of increased Notch1 abundance. Network pharmacology, qRT-PCR profiling of six intersection targets, and molecular docking were integrated to prioritize receptor candidates and generate testable hypotheses. Dex improved cell viability and reduced myocardial injury following H/R. Dex increased alpha-2A adrenergic receptor (Adra2a) and alpha-2B adrenergic receptor (Adra2b) mRNA expression and reduced Notch1/Hes1 expression. Notch1 overexpression weakened several Dex-associated protective effects. Network pharmacology and six-target qRT-PCR validation prioritized ADRA2A and ADRA2B as Dex-responsive receptor candidates. Molecular docking further predicted favorable Dex binding to ADRA2B and ADRA2A, with AutoDock Vina scores of - 8.8 and - 7.4 kcal/mol, respectively. Dex attenuated H/R-induced injury in H9c2 cells. This protective phenotype was accompanied by increased Adra2a and Adra2b mRNA expression and reduced Notch1/Hes1 expression, whereas Notch1 overexpression weakened several Dex-associated protective effects. These correlative findings propose a hypothesis-generating model, providing a focused rationale for future studies to investigate the specific receptor-level mechanisms underlying Dex-mediated cardioprotection.