Salidroside rescues hypoxic cardiomyocytes by regulating the EGLN1/HIF‑1α pathway

Myocardial infarction is characterized by oxygen deficiency caused by arterial flow restriction. Salidroside (SAL) protects against myocardial damage via antioxidant production and inhibition of apoptosis. The present study aimed to investigate potential rescue mechanism of SAL on hypoxic cardiomyocytes. H9C2 cardiomyocytes were divided into normoxia, hypoxia and hypoxia + SAL groups. The inhibitory rate of hypoxia and the optimal concentration and rescue effect of SAL were determined using Cell Counting Kit-8 assay and flow cytometry. Ca²⁺ concentration following hypoxia treatment and SAL intervention were detected by Fluo-4/acetoxymethyl. Tandem mass tag (TMT) proteomics was used to analyze the differential expression of hypoxia-associated proteins among the three groups. SAL exerted a protective effect on hypoxia-injured cardiomyocytes by enhancing aerobic metabolism during hypoxia and rescuing cardiomyocytes from hypoxic damage. SAL promoted cell proliferation, decreased apoptosis and increased Ca²⁺ levels in cell membranes of hypoxic cardiomyocytes. TMT proteomics results showed that the expression levels of intracellular hypoxia inducible factor-1 (HIF)-1α and Egl-9 family HIF 1 (EGLN1) in H9C2 cells were elevated under hypoxic conditions. However, SAL significantly decreased expression levels of HIF-1α and EGLN1. SAL inhibited mitochondrial calcium overload in hypoxic cardiomyocytes and attenuated expression of hypoxia-associated factors. SAL exerted its rescue effect on hypoxic cardiomyocytes through the EGLN1/HIF-1α pathway, thereby suppressing cardiomyocyte apoptosis, improving mitochondrial energy metabolism efficiency and rescuing cardiomyocytes from hypoxic injury.