Exercise Improves Visual Deficits Tested by Visual Evoked Potentials in Streptozotocin-Induced Diabetic Rats

Abstract

Visual evoked potentials (VEP) can be used as an objective non-invasive method to study the electrical activity of the visual system. Latency and amplitude measurements of VEP demonstrated that diabetes mellitus has been associated with increases in the latencies whereas the amplitude measurements revealed contradictory results. Although physical exercise has been reported to reduce the complications of diabetes mellitus, the effect of exercise on the visual system remains unknown. We investigated the effects of long-term moderate physical exercise on VEP in streptozotocin (STZ)-diabetic rats. We also measured brain thiobarbituric acid-reactive substances (TBARS) to explore the possible contribution of lipid peroxidation on the visual system. Animals were divided into four groups: control (C), control exercise (CE), diabetic (D) and diabetic exercise (DE) groups. Diabetes was induced by a single intraperitoneal injection of STZ (60 mg/kg). Three days after the confi rmation of diabetes, DE and CE groups were trained by running on a motor-driven treadmill with a progressive eightweek programme. The animals began running at 10 m/min, 0° slope, 10 min/day and reached a level of 28 m/min, 6° slope, 60 min/day by week 8. TBARS were elevated and VEP latencies were delayed in diabetic rats, indicating diabetes-induced defects in the optic pathway. These prolonged latencies were restored by exercise training. VEP amplitudes of the DE group were found unaltered with the exception of a decrement in P 2 N 2 which represents an early component of VEP, suggesting that exercise improves visual system defects in diabetic animals at different levels of the optic pathway. diabetes mellitus; visual evoked potentials; exercise; lipid peroxidation; rat © 2007 Tohoku University Medical PressPhysical exercise is well known to have many benefi cial effects on human health. Recently, attention has largely focused on the increase of free radicals generated during exercise, especially during aerobic activities. This increase is related to the elevation of electron transport fl ux, mitochondrial oxygen consumption, energy demand, oxygen supply and body

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Can regular moderate exercise lead to changes in miRNA-146a and its adapter proteins in the kidney of streptozotocin-induced diabetic male rats?

“…Th ey received an intraperitoneal (i.p.) injection of streptozotocin (STZ) 60 mg/kg BW dissolved in 0.1 mol/l citrate buff er (pH 4.5) aft er fasting for 12 h (Ozkaya et al 2007). Control groups received an i.p.…”

The Role of Physical Exercise on Lipid Peroxidation in Diabetic Complications

“…As an early marker of visual system deficits observed in diabetic state, visual evoked potential (VEP) latencies were measured in STZ-induced diabetic rats in our laboratories. The results of the previous studies were demonstrated that visual evoked potential (VEP) latencies were prolonged in STZ-induced diabetic rats whereas the latencies were restored by moderate physical exercise [60,141,142]. The VEP alterations were found to be accompanied with the increased TBARS concentration in the brain tissues of the diabetic rats.…”