SDH Assay

The succinate dehydrogenase, or SDH, assay enables us to distinguish between oxidative and low-oxidative muscle fibers. SDH is an enzyme that is found in the inner mitochondrial membrane that is active during the citric acid cycle (Krebs cycle), where it oxidizes succinate to fumarate.

Nitro blue tetrazolium is used to stain for SDH, which gives a purple color and visualizes of a muscle cell's ability to work under aerobic conditions. SDH is located in the mitochondria, and given the nature of mitochondrial placement within the cell, a stained cell can appear mottled. More intensely stained cells will be more oxidative than pale or non-stained fibers.

Histochemical assay of muscle fibers using the enzyme succinate dehydrogenase. Muscle fibers are illustrated in different shapes and sizes, laying close to each other. The oxidative muscle fibers are colored dark purple and the low-oxidative fibers are lighter colored. Most of the fibers in this illustration are light colored and are therefore low-oxidative muscle fibers

Fig.1 SDH staining of skeletal muscle

Referred from:

Article

Histochemistry staining