Effects of Ginseng Supplementation and Endurance-Exercise in the Artery-Specific Vascular Responsiveness of Diabetic and Sedentary Rats

Abstract

This study examined the effects of 12 weeks North-American ginseng supplementation, exercise training, and sedentary behavior on vascular responses in type I diabetic rats. The following hypotheses were tested: (1) ginseng supplementation would result in improved vascular responsiveness and sensitivity; (2) exercise training would result in further improvement in these vascular responses; (3) control rats with no access to exercise would show a depressed vascular response compared to control rats that were not exposed to a sedentary lifestyle. Groups: non-diabetic sedentary control (C_S), sedentary diabetic (D_S), sedentary diabetic with ginseng supplementation (D_S+GS), diabetic with ginseng supplementation and high-intensity endurance exercise (D+GS+EX), and control not exposed to sedentary behavior (C). Diabetes was induced by streptozotocin. Arteries were excised, cleaned, and mounted onto a myography system. Percent vasorelaxation to acetylcholine (ACh) (10^-8 M ACh to 10^-4 M ACh) of the carotid artery was similar in C_S (57 ± 31%), C (66 ± 35%), D_S (58 ± 36%), D+GS+Ex (71 ± 37%), and D_S+GS (64 ± 37%) (p > 0.05). Percent vasorelaxation of the aorta was smaller in C_S (23 ± 17%) compared to C (46 ± 35%), D_S (60 ± 40%), D+GS+Ex (64 ± 40%), and D_S+GS (56 ± 39%) (p < 0.05), and smaller in C compared to D+GS+Ex (p < 0.05). In the femoral, the percent vasorelaxation was reduced in D_S (18 ± 16%) compared to all the other conditions (C_S, 43 ± 22%; C, 79 ± 28%; D+GS+Ex, 55 ± 27%; D_S+GS, 45 ± 26%; p < 0.05), but larger in C compared to the other conditions (C_S, D_S, D+GS+Ex, D_S+GS; p < 0.05). Diabetes and sedentary lifestyle have detrimental effects on vascular responses that are evident in the femoral arteries of the diabetic rats. Ginseng supplementation restored the loss of sensitivity, with no added vascular protection of exercise training.

Keywords: aerobic training; endothelium-dependent vasorelaxation; type I diabetes; vascular kinetics; vessel myography.

FIGURE 1

Model fits for a representative carotid (A), aorta (B), and femoral (C). Open circles are the raw data and the red lines represent the linear (baseline) and mono-exponential (ACh infusion starting at time 0) model fits.

FIGURE 2

Time-to-Steady-Stated of the vasorelaxation response for each vessel in each experimental conditions. ^∗ Significantly different from Control Sedentary; † significantly different from Control.

FIGURE 3

Scatterplot displaying the time-to-steady-state of the vasorelaxation response as a function of serum glucose for the carotid and aorta arteries.

FIGURE 4

vasorelaxation responses to cumulative doses of ACh. ^∗ Significantly different from C_S; † significantly different from C; § significantly different from D_S; ‡ significantly different from D_S+GS; # significantly different from D+GS+Ex.