Clinical evaluation of oxidative stress in patients with diabetes mellitus type II -- impact of acute exercise.

BACKGROUND/AIM: Exercise is a well recognized model of oxidative stress and, also, an important tool in diabetes management. The aim of our study was to evaluate oxidative stress in patients with diabetes mellitus type 2 and to determine influence of acute exercise training on the investigated parameters.
METHODS: To evaluate oxidative stress in the patients, we determinated following parameters: triglycerides (TG), total cholesterol, low density lipoprotein cholesterol (LDL), oxidized LDL cholesterol (Ox LDL), superoxide dismutase (SOD), glutathione peroxidase (GSHPx), plasminogen activator inhibitor (PAI) which were measured at rest and immediately after the acute bout of cardiopulmonary exercise cycle-ergometer test.
RESULTS: In basal condition, diabetic patients compared to controls have significant higher values of TG (3.12 +/- 1.09 vs 1.74 +/- 0.9 mmol/L, p < 0.01), Ox LDL (84.73 +/- 16.90 vs 79.00 +/- 29.26 mmol/L, p < 0.05) and SOD enzyme activity (913.38 +/- 120.36 vs 877.14 +/- 153.18 U/g Hb, p < 0.05). During the acute exercise test, there was significant increase of Ox LDL in both the study patients (from 84.73 +/- 16.90 to 92.33 +/- 23.29 mmol/L, p < 0.05) and in the control group (from 79.00 +/- 29.26 to 89.30 +/- 29.07 mmol/L, p < 0.05). SOD activity was significantly increased in both groups during exercise, in diabetic patients from 913.38 +/- 120.36 to 921.50 +/- 130.03 U/gHb, p < 0.05, and in the controls from 877.14 +/- 153.18 to 895.00 +/- 193.49, U/gHb, p < 0.05. GSH-Px activity was significantly increased only in the diabetic patients after the acute exercise (from 45.04 +/- 11.19 to 51.81 +/- 15.07 U/gHb, p < 0.01), but not in the controls (from 44.63 +/- 13.73 to 43.97 +/- 25.97 U/gHb, p = ns). PAI significantly decreased during the exercise test, only in the healthy subjects (from 2.60 +/- 0.35 to 2.22 +/- 0.65, p < 0.05). Type 2 diabetic patients with complications had only significant increase in GSH-Px activity (from 47.10 +/- 7.37 to 54.52 +/- 11.97 U/gHb, p < 0.01).
CONCLUSION: Elevated Ox LDL, SOD and GSH-Px levels are associated with acute exercise in type 2 diabetic patients. We suggest that it could be a compensatory mechanism to preventing free radicals tissue damage. We hypothesize that a physical training program induces an enhance of muscular and liver antioxidant enzymes activity and reduces oxidative stress. Further studies are needed to explore the relationship between exercise and antioxidant system in diabetic patients with and without complications.