Histochemical demonstration of skeletal muscle fibre types and capillaries on the same transverse section

Serial transverse sections of m. vastus lateralis biopsies from six healthy men were reacted: (1) for myofibrillar adenosine triphosphatase (mATPase) to identify fibre types; or, (2) with alpha-amylase, periodic acid-Schiff (alpha PAS) to visualize capillaries. Sections were also processed with a new histochemical method for identification of fibre types and capillaries on the same skeletal muscle slice (mATPase/alpha PAS). Fibre type composition using either method was 41% type I, 37% type IIA and 22% type IIB. Types I, IIA and IIB least diameter areas (mean +/- SE, micron2) were similar in sections processed for mATPase/alpha PAS or mATPase (3976 +/- 338, 5187 +/- 373 and 4389 +/- 514 vs. 4092 +/- 345, 5100 +/- 360 and 4289 +/- 474, respectively). The number of capillaries per mm2 and per fibre did not differ in sections processed using the alpha PAS (315 +/- 29 and 1.48 +/- 0.12) or mATPase/alpha PAS (317 +/- 25 and 1.43 +/- 0.10) method. The number of capillaries was greater (P less than 0.05) around types I or IIA than type IIB fibres whether a section was processed for mATPase/alpha PAS (4.5 +/- 0.2 or 4.6 +/- 0.2 vs. 3.4 +/- 0.3) or when fibre profiles of serial sections reacted for mATPase or alpha PAS were 'matched' (4.5 +/- 0.2 or 4.4 +/- 0.2 vs. 3.4 +/- 0.3). The results indicate that histochemical and morphometric measures can be made on the same transverse section using the new method with substantial savings of time, cost and energy.