Objective: To summarize the improvement of various muscle staining techniques and discuss their application in diagnosis of neuromuscular diseases.
Methods: Three hundred cases of skeletal muscle biopsy samples were examined by histopathological methods. The flash-freezing techniques were used for the preparation of frozen section, which were stained with HE, Gomori trichromic (GMR), glycogen (PAS), and fat acid (oil red O); the enzyme histochemical staining with myosin adenosine triphosphatase (ATPase), and NADH-TR. Those stained methods had been improved. The immunohistochemical staining with dystrophin; and transmission electronic microscopy were used.
Results: Deepfreeze with heteropentane-liquid nitrogen and flash-freezing techniques could avoid artifacts of ice crystal vacuolation. GMR staining mainly showed the degenerative and necrotic lesions of mitochondria and muscle fibers. Oil red O staining showed the increase of lipid in muscle fibers. PAS staining mainly showed glycogen and glycoprotein. Application of frozen sections in muscular tissue was better than that of paraffin sections. NADH-TR staining and ATPase staining could distinguish the two types of muscle fibers, and show the changes of inner structure of muscle fibers and mitochondria enzymes.
Conclusion: The distribution and characteristic pathological changes of the two types of muscle fibers can be showed clearly by enzyme and non-enzyme histochemical staining techniques of the skeletal muscle. These methods can compliment with each other. Only after understanding the technical principles can we master and apply these methods.