Effect of Resistance Training on Capillary Density Around Slow and Fast Twitch Muscle Fibers in Diabetic and Normal Rats

Abstract

Background:It is well accepted that skeletal muscle conforms to exercise stimulus by increasing capillary density and angiogenesis, but there is less evidence regarding the effect of resistance training on capillary density in flexor hallucis longus (FHL) and soleus muscle.Objectives:In this study, we evaluated the effect of resistance training on capillary density around soleus and FHL muscles in type 1 diabetic rats.Materials and Methods:Thirty-six male rats were divided into four groups: (1) control; (2) diabetic; (3) diabetic trained and (4) control trained (n = 9 each). A Single intraperitoneal injection of Streptozotocin at a dose of 55 mg/kg was used for induction of diabetes. The rats in the trained group undertook one training session per day for 3 days/week. Training was done with the use of a 1 meter high ladder inclined at 80°. After 4 weeks, the plasma nitrite concentrations were measured. Capillary/fiber ratio was determined around soleus and FHL muscles by immunohistochemistry.Results:Plasma Nitric Oxide (NO) concentration was increased after resistance training in diabetic animals (P < 0.05). Capillary/fiber ratio around the soleus muscle of diabetic group was more than control rats. Resistance training did not alter capillary/fiber ratio in diabetic animals (1.00 ± 0.6 vs. 1.07 ± 0.07, respectively). Capillary/fiber ratio around FHL muscle was significantly different between diabetic and control and did not alter after exercise (diabetes: 1.1702 ± 0.09; diabetic trained: 1.1714 ± 0.08; control: 0.79 ± 0.08; control trained: 0.73 ± 0.03). There was a positive correlation between plasma NO concentration and capillary density in the soleus muscle (R2 = 0.65).Conclusions:Resistance training could not improve capillary/fiber ratio in soleus and FHL muscle of diabetic animals in spite of increase in some angiogenic factors including NO.

Estrogen deficiency in ovariectomized rats: can resistance training re-establish angiogenesis in visceral adipose tissue?

“…Increases in the capillary network play important roles in improving aerobic capacity, facilitating oxygen transport, enhancing conductance, and increasing muscle contraction, thus increasing maximal oxygen uptake and physical conditioning. Karimian et al 39 demonstrated that Rt performed by climbing ladders does not change the capillary/fiber ratio in flexor hallucis longus (FHL) or soleus muscles but does increase plasma nitric oxide (NO) concentration, an important factor for regulating and enhancing angiogenesis in diabetic animals.…”

Resistance Exercise Training Attenuates the Loss of Endogenous GLP-1 Receptor in the Hypothalamus of Type 2 Diabetic Rats

“…The resistance training protocol was adapted from a previous study [ 28 ]. Rats in the exercise-trained group (DM + EXE) were trained to climb a 135-cm ladder (85 °C incline) with weight secured to their tails.…”

Cardiovascular Adaptations Induced by Resistance Training in Animal Models

“…In concert with the findings described above, Mota et al, 62 showed the effectiveness of RT to treat endothelial dysfunction and prevent an increase in arterial BP in type 1 diabetic rats. Karimian et al 63 showed increased plasma angiogenic factors such as NO in diabetic rats after RT.…”