Newsletter

Acute myocardial infarction (AMI) causes rapid changes in the cardiac microenvironment, including impaired blood flow, inflammatory cell recruitment, and alterations in lymphatic function. Understanding these dynamic responses is important for investigating the progression of cardiac injury and subsequent tissue recovery.

Mouse model: Acute myocardial infarction (AMI) mouse model

• Model & Imaging Approach
  A Rose Bengal-mediated photothrombosis model was established in C57BL/6 wild-type mice. Following Rose Bengal administration, 561 nm laser illumination was used to induce localized thrombus formation. Blood vessels and platelets were visualized using CD31 and CD41 labeling, respectively. FSD555 was used as a fluorescent dye control to evaluate whether laser illumination alone induced changes in platelet accumulation or blood flow.

• Key Imaging Findings
  Following laser illumination, progressive platelet accumulation was observed within cardiac blood vessels, accompanied by disruption and eventual arrest of blood flow. In contrast, the fluorescent dye control showed no noticeable changes in platelet accumulation or blood flow under the same illumination conditions.

• Research Insight
  This model enables real-time visualization of the sequence of thrombus formation and blood flow disruption during myocardial microinfarction. It provides a useful platform for investigating platelet vascular interactions, microvascular obstruction, and the early events associated with ischemic cardiac injury.

• Model & Imaging Approach
  LysM-GFP transgenic mice were fed a high-fat diet for up to 8 weeks. Cardiac blood vessels were labeled with CD31, immune cells expressing LysM-GFP were visualized in vivo, and lipid droplets were labeled with SF44. Z-stack imaging was performed from the cardiac surface into deeper tissue layers to examine the spatial distribution of lipids and immune cells.

• Key Imaging Findings
  Substantial lipid droplet accumulation was observed on the cardiac surface, while immune cells were predominantly detected in deeper tissue regions. Compared with the 4-week stage, 8 weeks of high-fat diet exposure resulted in increased lipid deposition accompanied by greater immune cell infiltration.

• Research Insight
  These findings reveal distinct spatial patterns of lipid accumulation and immune cell localization within the heart. By imaging across multiple tissue depths, intravital microscopy provides a dynamic and spatially resolved view of how prolonged high-fat diet exposure alters the cardiac microenvironment and is associated with progressive immune responses.

DATE: October 22, 2026