Myocardial Infarction - Nitroblue Tetrazolium Stain

Nitroblue Tetrazolium (NBT) is a substrate for lactic dehydrogenase (LDH). This enzyme transforms the NBT from a yellow substance to a formazan salt which is deep purple in color. Thus NBT staining is useful to detect viable myocardium (purple) and the non-viable myocardium does not stain. Thus, NBT is a very sensitive technique to identify myocardial infarcts as early as 30 minute post infarction when the dead myocytes start leaking LDH into the bloodstream and do not transform NBT into formazan.The images below show examples of myocardial infarcts detected with NBT staining.

Triphenyl tetrazolium is also useful, giveing a paler burgundy collor to the myocardium. A disadvantage is that it is soluble in alcohol and the stain disappears if the tissue is exposed to alcohol.

A. The left upper image shows transverse sections of the ventrtricular myocardium from two different cases. The left image is normal myocardium without evidence of infarction. The image on the right shows a faint (pale brown area) of myocardial infarct in lateral and posterial wall.  in the left section. B. A circumferential left ventricular infarct is present in this image. Note the pale brown non-staining trabecular myocardium which contrasts with the compact zone myocardium staining purple. C. This example shows a transmural right ventricular infarct in addition to a transmural posterior infarct in the left ventricle. D. Thse three cuts show faint circumferential subendocardial infarct of the left ventricle and a massive transmural infarct of the right ventricle.


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