Exogenous MOTS-c mitigates myocardial ischemia-reperfusion injury: experimental and in silico evidence from rat heart...

The mitochondrial-derived peptide MOTS-c regulates metabolic and cellular stress responses, but its dose-response profile and direct cardioprotective mechanisms in myocardial ischemia-reperfusion injury (MIRI) remain undefined. This proof-of-concept study aimed to identify the optimal cardioprotective dose of exogenous MOTS-c and delineate its multi-pathway mechanisms using an ex vivo rat heart IR model with in silico support. Isolated Langendorff-perfused rat hearts underwent 30-min global ischemia and 60-min reperfusion with or without MOTS-c (0.25-0.7 mg/kg) delivered via Krebs-Henseleit buffer during the first 10 min of reperfusion. Hemodynamics, infarct size (TTC), oxidative stress markers, inflammation, and apoptotic gene expression were quantified. Peptide-protein interactions with survival pathways were predicted computationally. MOTS-c at 0.5 mg per kg conferred maximal protection, producing a 73% reduction in infarct size compared with ischemia-reperfusion alone, improving heart rate, left ventricular developed pressure, and rate-pressure product, and lowering end-diastolic pressure. Lactate dehydrogenase release decreased by 65%. Antioxidant defenses improved with increased superoxide dismutase, catalase, and glutathione redox ratio, along with reduced lipid peroxidation. Myeloperoxidase activity normalized, pro-apoptotic genes including caspase 3, caspase 7, caspase 9, BAX, and PARP were downregulated, while cytoprotective genes including BCL2, GPX4, and FOXO were increased. Molecular docking demonstrated high-affinity interactions of MOTS-c with MAPK, mTOR, AMPK, NRF2, PI3K, and caspase 3. This ex vivo study identifies 0.5 mg/kg as the optimal dose within the tested range, producing coordinated anti-apoptotic, antioxidant, and anti-inflammatory effects. Although the isolated heart model isolates direct myocardial actions, the lack of systemic influences and limited dose range necessitate broader dosing and pharmacokinetic studies before translational application.