In diabetic mice, giving semaglutide for 8 weeks helped keep tiny heart blood vessels healthy. It fixed vessel structure, reduced scar tissue around vessels, and lowered inflammation, oxidative stress, and cell death. These benefits were linked to several molecular pathways that semaglutide turned on or off.

Cardiac microvascular injury from hyperlipidaemia and hyperglycaemia is associated with increased major adverse cardiovascular events (MACE). Semaglutide, a long-acting GLP-1 receptor agonist, reduces diabetic cardiovascular complications beyond its glycaemic and weight-lowering effects. However, the impact of semaglutide on diabetes-induced coronary microvascular injury and the integrated mechanisms involved remain unclear. A combined streptozotocin (STZ) and high-fat diet (HFD) induced diabetes model was established in ApoE^-/- mice, followed by 8 weeks of semaglutide treatment. Microvascular morphology in myocardial tissue was assessed by scanning electron microscopy, and CD31 expression was evaluated using immunofluorescence. Key pathways related to oxidative stress, inflammation, and apoptosis were examined by TUNEL staining, western blotting (WB), and reverse-transcription quantitative real-time PCR (RT-qPCR). Diabetic mice showed disrupted cardiac microvascular structure and reduced microvascular density. Semaglutide attenuated or reversed these changes. It reduced advanced glycation end products (AGEs) and their receptors, activated the Nrf2/HO-1/NQO1 pathway, inhibited the MCP-1/CCR2a/NF-κB pathway, lowered inflammatory cytokines, and reduced apoptosis, exerting a protective effect on the cardiac microvascular system. Early and sustained semaglutide treatment mitigates diabetes-related cardiac microvascular injury via multiple mechanisms, including preserving microvascular structure and density, inhibiting perivascular fibrosis, and attenuating inflammation, oxidative stress, and apoptosis.