MORPHOLOGICAL ADAPTATION OF CAPILLARY NETWORK IN COMPENSATORY HYPERTROPHIED RAT PLANTARIS MUSCLE

The aim of this study was to examine the morphological adaptation of t he capillary network in hypertrophied plantaris muscles by examining b oth capillary numbers and luminal circumferences. Hypertrophy of the p lantaris muscle was induced by myectomy of the gastrocnemius muscle. T his hypertrophy was characterised by increases in muscle mass and fibr e cross-sectional area. All capillary parameters were determined using morphometric methods in perfusion-fixed plantaris muscle. Increased c apillary-to-fibre ratio was observed in the overloaded plantaris muscl e while no change was observed in the capillary luminal circumference. No differences were observed in the capillary density and the capilla ry-to-fibre perimeter ratio of the normal and the hypertrophied planta ris muscle. These results indicated that chronic overload-induced neoc apillarization, but not enlargement of capillary luminal circumference , contributed to the prevention of decreases in the capillary-to-fibre perimeter ratio in the plantaris muscle in the hypertrophied process.