Protective Effect of Isoflurane on Hypoxia/Reoxygenation‐Induced Myocardial Injury via miR‐548a‐5p Regulation of PTEN

ABSTRACT

Ischemia–reperfusion (I/R) injury induces cardiomyocyte apoptosis, oxidative stress and elevated myocardial injury markers. This study aimed to investigate whether the microRNA‐548a‐5p (miR‐548a‐5p)/phosphatase and tensin homolog deleted on chromosome 10 (PTEN) axis mediates the cardioprotection conferred by isoflurane (ISO). An in vitro hypoxia/reoxygenation (H/R) injury model was established using H9c2 cardiomyocytes, including control, H/R and ISO pretreatment groups. We detected miR‐548a‐5p and PTEN expression by RT‐qPCR, and evaluated cell viability, apoptosis, myocardial injury markers including creatine kinase‐MB (CK‐MB), cardiac troponin I (cTnI), lactate dehydrogenase (LDH), and reactive oxygen species (ROS) using CCK‐8, flow cytometry, ELISA and DCFH‐DA staining. Dual‐luciferase reporter assay validated the direct binding between miR‐548a‐5p and PTEN. H/R downregulated miR‐548a‐5p and upregulated PTEN, accompanied by decreased cell viability, increased apoptosis, myocardial injury and oxidative stress. 1.0% ISO pretreatment reversed these adverse alterations, restored miR‐548a‐5p and suppressed PTEN expression. miR‐548a‐5p inhibition attenuated ISO‐elicited cardioprotection, whereas PTEN silencing restored the cardioprotective capacity compromised by miR‐548a‐5p inhibition. In conclusion, ISO exerts cardioprotective effects via the miR‐548a‐5p/PTEN signaling axis, offering a potential therapeutic target for I/R injury.