Identification of Skeletal Muscle Fiber Types with Histochemical Staining Technique

Using ATPase staining to identify the skeletal muscle fiber types,slow-twitch type(typeⅠ) and fast-twitch type(typeⅡ).Several adult male Sprague-Dawley(S-D) rats were euthanized,and their medial gastrocnemii of left hind limbs were collected immediately and processed into frozen cross sections at a thickness of 10 μm in a freezing cryostat at-20℃.The two types of muscle fibers were identified after staining for myofibrillar ATPase.After alkaline pre-incubation(pH 10.4),the type Ⅱ muscle fibers were stained to dark brown,the typeⅠjust stained slightly;on the contrary,after acid pre-incubation(pH 4.3),the type Ⅰ muscle fibers were stained to dark brown,the typeⅡ just stained slightly.The results demonstrate,no matter using an acid pre-incubation(pH 4.35)or an alkaline pre-incubation(pH 10.4),both kinds of ATPase staining can identify the types of skeletal muscle fibers.This experiment not only makes students understand the types of skeletal muscle fibers better,but also let them contact the histochemical staining technique,which is widely used in life scientific studies currently.The cost of the reagents and consumptive materials in this experiment is not expensive,so it is worth using and spreading.