The different histochemical ATPase properties of myosins separating the muscle fiber
types have been utilized in diagnostic muscle biopsy routine for more than four decades.
The ATPase staining method is rather laborious and has several disadvantages, such
as weakening of staining over time and non-specific staining of capillaries, making
the distinction of extremely atrophic muscle fibers difficult. We have developed a
reliable and advanced immunohistochemical myosin double staining method for the identification
of fiber types, including highly atrophic fibers in routine diagnostics. With this
double staining method, we are able to distinguish among type I (ATPase type 1), IIA
(ATPase type 2A), IIX (ATPase type 2B) and remodeled ATPase type 2C fibers expressing
both fast and slow myosins using a one slide technique. Immunohistochemical double
staining of myosin heavy chain isoforms can be used as an alternative for the conventional
ATPase staining method in routine histopathology. The method provides even more detailed
information of fast fiber subtypes and highly atrophic fibers on one single slide.