Stereological analysis of capillaries in electrostimulated human muscles

The effects of two methods of electrical stimulation on the capillary density in skeletal muscle was studied. Twenty-two male physical education students randomly divided into two groups participated in the experiment. Groups I and II were subjected to the procedure of electrical stimulation of m. triceps surae daily for a period of 21 days. Group I was stimulated by an alternating current of relatively low frequency (50 Hz), and group II was stimulated by an alternating current of relatively high frequency (2000 Hz). Biopsy specimens were obtained from the lateral portion of m. gastrocnemius 1 week before the stimulation and 1 day after the completion of the stimulation period. The capillary network was analyzed using morphometric and stereological techniques. Significant changes were found for capillary number in cross section, capillary density, intercapillary distance, tissue cylinder corresponding to one capillary (Krogh's cylinder) in both groups, and for capillary number-to-fiber area ratio in group I. Differences between the results of groups I and II were not significant in any cases. The changes observed speak in favor of an improved capillary supply to skeletal muscle after electrical stimulation.