Journal of Applied Physiology, Vol 56, Issue 1 244-247, Copyright © 1984 by American Physiological Society
Estimation of skeletal muscle fiber number by mean fiber dry weight
B. F. Timson and G. A. Dudenhoeffer
The purpose of this study was to determine whether skeletal muscle fiber
number could be accurately estimated by the determination of mean fiber dry
weight (MFD) and total muscle dry weight. The muscles studied were the
soleus, plantaris, gastrocnemius, extensor digitorum longus, tibialis
anterior, and biceps brachii of the rat, the anterior latissimus dorsi of
the chicken, and the flexor carpi radialis of the cat. Bundles of fibers
were carefully separated from the muscle following nitric acid digestion
(ND) and placed in groups of similar length. MFD determined from 400 to 800
fibers from each group was used to estimate the number of fibers in the
remainder of the group. Estimated fiber number was compared with the fiber
number determined in the muscle from the contralateral limb by the ND
method. No difference in fiber number was observed between the ND method
and the MFD estimation method for any of the muscles used in the study. The
results indicate that the MFD estimation method is an accurate and
relatively rapid method of fiber number determination in skeletal muscle.
