Novel Fluorescence-Based Methods to Determine Infarct and Scar Size in Murine Models of Reperfused Myocardial...

Area of Science:

• Cardiovascular Research
• Histopathology
• Animal Models

Background:

• Assessing infarct and scar size post-myocardial infarction (MI) is crucial for evaluating cardioprotective treatments in animal studies.
• Current histological methods are tissue-intensive and limit parallel analyses.
• There is a need for improved techniques to quantify infarct size and area at risk more efficiently.

Purpose of the Study:

• To develop and validate a new fluorescence staining technology for determining infarct area and area at risk after MI.
• To compare the efficacy of this new method with traditional staining techniques like TTC and Sirius Red.
• To assess the feasibility of performing parallel analyses on the same tissue sample.

Main Methods:

• Male mice underwent induced myocardial infarction (MI).
• Hearts were extracted at various time points (24 h, 7, 21, 28 days) post-MI.
• Fluorescence staining using Hoechst and phalloidin was employed, with subsequent comparison to TTC/Evans Blue and Sirius Red staining.

Main Results:

• The fluorescence staining method demonstrated high correlation with TTC/Evans Blue staining at 24 h post-MI (r=0.8334).
• For scar size determination (>7 days post-MI), fluorescence staining showed strong accuracy compared to Sirius Red (r=0.9752), Masson's (r=0.9920), and Gomori's Trichrome (r=0.8082).
• The protocol allowed for clear visualization of infarct area, area at risk, and co-localization of immune cells.

Conclusions:

• The developed fluorescence staining procedure is a viable alternative to traditional methods for determining post-MI infarct and scar size.
• This technique offers significant advantages, including unbiased software-assisted analysis and preservation of tissue for additional studies.
• The method enhances data quality and supports the 3R principles in animal experimentation by reducing animal numbers.