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 m uscle capillarity and oxidative capacity in adult rats. Methods: Arter ial insufficiency was created by ligation (LIG) of the right femoral a rtery, and exercise training (TR) was performed on a rodent treadmill. The left hindlimb served as a normally (NORM) perfused control. Capil lary:fiber ratio, number of capillary contacts per fiber, and citrate synthase activity (CS) were evaluated in the plantaris (Plant) and sol eus (Sol) muscles. Results: In sedentary rats, CS was similar between LIG and NORM (Plant: 24.4 vs. 24.3 mu mol.min(-1).g(-1); Sol: 16.6 vs. 16.9 mu mol.min(-1).g(-1)), but capillaries per fiber and capillary c ontacts per fiber were significantly elevated in the plantaris muscle of LIC (2.46 vs. 2.10 caps/fiber, 5.78 vs. 5.03 capillary contacts). C S was elevated in both limbs of TR but was lower in LIG than in NORM ( Plant: 28.5 vs. 32.4 mu mol.min(-1).g(-1); Sol: 21.1 vs. 24.9 mu mol.m in(-1).g(-1)). Treads mill training did not significantly affect capil larity in NORM. However, muscles in the ligated limb of TR tended to h ave greater capillarity than comparable muscles in either NORM of TR o f LIG in SED. Conclusions: These results demonstrate capillary prolife ration in the plantaris but not soleus muscle of rat hindlimbs with fe moral artery ligation. Capillarity and CS adaptations were not obligat orily related in LIG, and femoral artery ligation and exercise trainin g appeared to have interactive effects on skeletal muscle capillarity.