Femoral artery ligation stimulates capillary growth and limits training-induced increases in oxidative capacity in rats.

OBJECTIVE

The purpose of this study was to assess the interaction of arterial insufficiency and exercise training on soleus and plantaris muscle capillarity and oxidative capacity in adult rats.

METHODS

Arterial insufficiency was created by ligation (LIG) of the right femoral artery, and exercise training (TR) was performed on a rodent treadmill. The left hindlimb served as a normally (NORM) perfused control. Capillary:fiber ratio number of capillary contacts per fiber, and citrate synthase activity (CS) were evaluated in the plantaris (Plant) and soleus (Sol) muscles.

RESULTS

In sedentary rats, CS was similar between LIG and NORM (Plant: 24.4 vs. 24.3 mumol.min-1.g-1; Sol: 16.6 vs. 16.9 mumol.min-1.g-1), but capillaries per fiber and capillary contacts per fiber were significantly elevated in the plantaris muscle of LIG (2.46 vs. 2.10 caps/fiber, 5.78 vs. 5.03 capillary contacts). CS was elevated in both limbs of TR but was lower in LIG than in NORM (Plant: 28.5 vs. 32.4 mumol.min-1.g-1; Sol: 21.1 vs. 24.9 mumol.min-1.g-1). Treadmill training did not significantly affect capillarity in NORM. However, muscles in the ligated limb of TR tended to have greater capillarity than comparable muscles in either NORM of TR of LIG in SED.

CONCLUSIONS

These results demonstrate capillary proliferation in the plantaris but not soleus muscle of rat hindlimbs with femoral artery ligation. Capillarity and CS adaptations were not obligatorily related in LIG, and femoral artery ligation and exercise training appeared to have interactive effects on skeletal muscle capillarity.