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The blue infarct: a simple method for the quantification of myocardial damage in the rat
C A Flores1, R Melo, S H Ferreira
1Departamento de Farmacologia da Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brasil.
Insights
Evans blue dye revealed increased content in infarcted rat heart regions after coronary occlusion (CO). Dexamethasone treatment prevented this dye extravasation, suggesting its role in protecting against myocardial damage.
Area of Science:
- Cardiovascular Research
- Pharmacology
- Myocardial Infarction Studies
Background:
- Coronary occlusion (CO) leads to myocardial infarction, affecting heart tissue.
- Understanding blood flow dynamics in infarcted areas is crucial for therapeutic development.
- Evans blue dye is a common marker for assessing tissue perfusion and damage.
Purpose of the Study:
- To investigate blood flow and dye extravasation in the infarcted left ventricle of rats after coronary occlusion.
- To evaluate the effects of dexamethasone, indomethacin, and BW755C on dye extravasation in myocardial infarction.
Main Methods:
- Intravenous injection of Evans blue dye into rats 24 hours prior to left coronary occlusion.
- Quantification of dye content in different cardiac ventricles post-occlusion.
- Administration of dexamethasone, indomethacin, or BW755C to assess their impact on dye extravasation.
Main Results:
- A progressive 2-3 fold increase in Evans blue dye content was observed in the infarcted portion of the left ventricle up to 24 hours post-coronary occlusion.
- No significant difference in dye content was found between the right ventricle and the non-infarcted portion of the left ventricle.
- Dexamethasone administration abolished dye extravasation, while indomethacin and BW755C did not.
Conclusions:
- The increased dye content in the infarcted area suggests the presence of collateral circulation or blood backflow.
- Dexamethasone demonstrates a protective effect by preventing dye extravasation, indicating a potential role in mitigating myocardial infarction damage.
Abstract:
Evans blue dye was injected iv into rats 24 h before left coronary occlusion (CO) and the dye content extracted with formamide was estimated after various time intervals in the 1) right ventricle, 2) left ventricle above the ligature and 3) the rest of the left ventricle. There was no difference between portion 1 and 2 but portion 3 showed a progressive increase in dye content (2 to 3 fold) up to 24 h after CO. This result indicates that either the infarcted area possesses collateral circulation or a continuous blood backflow occurred. Dexamethasone (0.5 mg/kg) but not indomethacin (2 mg/kg) or BW755C (10 mg/kg) abolished extravasation of the dye.