Nerve function and oxidative stress in diabetic and vitamin E-deficient rats.
Nerve dysfunction in diabetes is associated with increased oxidative stress. Vitamin E depletion also leads to enhanced presence of reactive oxygen species (ROS). We compared systemic and endoneurial ROS activity and nerve conduction in vitamin E-depleted control and streptozotocin-diabetic rats (CE- and DE-), and in normally fed control and diabetic animals (CE+ and DE+). Nerve conduction was reduced in both diabetic groups. Vitamin E depletion caused a small further nerve conduction deficit in the diabetic, but not in the control animals. The combination of vitamin E deficiency and streptozotocin-diabetes (group DE-) appeared to be lethal. In the remaining groups, an important rise in sciatic nerve malondialdehyde (MDA) was observed in the vitamin E-depleted control rats. In contrast, plasma MDA levels were elevated in group DE+ only, whereas hydrogen peroxide levels were increased in group CE-. Endoneurial total and oxidized glutathione and catalase were predominantly elevated in group DE+. These data show that nerve lipid peroxidation induced by vitamin E depletion does not lead to reduced nerve conduction or changes in antioxidant concentrations as observed in STZ-diabetes. The marked systemic changes in MDA and antioxidants suggest that nerve dysfunction in experimental hyperglycemia is rather a consequence of systemic than direct nerve damage.
van Dam
P S
PS
Department of Medical Pharmacology, Rudolf Magnus Institute for Neurosciences, Utrecht University, The Netherlands.
van Asbeck
B S
BS
Bravenboer
B
B
van Oirschot
J F
JF
Gispen
W H
WH
Marx
J J
JJ
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000150:complications / Q000503:physiopathology*; D003929:Diabetic Neuropathies / Q000503:physiopathology*; D006861:Hydrogen Peroxide / Q000097:blood; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008833:Microcirculation; D009431:Neural Conduction / Q000502:physiology; D018384:Oxidative Stress / Q000502:physiology*; D010525:Peripheral Nerves / Q000098:blood supply; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012584:Sciatic Nerve / Q000378:metabolism; D014811:Vitamin E Deficiency / Q000503:physiopathology*
D000975:Antioxidants; D017382:Reactive Oxygen Species; D008315:Malondialdehyde; D006861:Hydrogen Peroxide