Delayed Processing of Muscle Biopsy Specimens: Does it Really Compromise Enzyme Histochemistry?

Abstract

Delayed freezing of a skeletal muscle biopsy for enzyme histochemistry reportedly compromises pathologic diagnosis. We specifically examined the effects of delayed freezing on enzyme histochemistry. Normal (2) and diseased (9) skeletal muscle biopsy specimens were divided into multiple sections for freezing. One cross-section was immediately frozen. The remaining cross-sections, kept at room temperature, were subsequently frozen at time intervals of 24 and 48 hr. Eight-um thick cross-sections of all frozen blocks were then stained with hematoxylin and eosin, alkaline phosphatase, oil red O , rapid Gomori trichrome, NADH, acid phosphatase, periodic acid Schiff, cytochrome C oxidase, esterase, sulfated alcian blue, and ATPase (differentiation at pH 4.6 and pH 9.8). Pathologic diagnoses in the diseased muscle group included: neurogenic atrophy (N = 4), chronic rnyopathy (N = 2), mitochondria1 niyopathy (N = 1), type I atrophy (N = 1), and nonspecific fiber atrophy (N = 1). At intervals of 30 min, 24 hr, and 48 hr delayed freezing, stained slides were compared in the normal and diseased muscles. No appreciable differences were observed in the quality of enzyme reactivity of the histochemical stains. We conclude that delays in freezing muscle biopsy specimens for up to 48 hr for enzyme histochemistry have no effect on staining quality for the examined stains. (The J Histotechnol 21:305–308, 1998)

Keywords:

• skeletal muscle