Effect of alpha-tocopherol on glucose uptake and contractility in rat skeletal muscle.
BACKGROUND
Free radicals and associated oxidative stress play an important role in the causation and subsequent complications of diabetes mellitus. Type I diabetes can be induced in experimental animals by administration of streptozotocin which causes selective destruction of B islet cells, probably by a free radical mediated mechanism. The objective of this study was to determine the effect of administration of alpha-tocopherol two weeks before and two weeks after streptozotocin injection on contractility and glucose uptake of rat hemidiaphragm.


METHODS
Male Wistar rats were used for this experiment. In the first phase, all the rats received an ordinary diet, while some were given alpha-tocopherol; in the second phase, diabetes was induced with streptozotocin, while the animals in the experimental group were given alpha-tocopherol two weeks before and two weeks after diabetes induction.


RESULTS
Streptozotocin decreased the height of the indirect contraction and the time for 50% decrease in height of contraction of indirect responses. At the same time, the glucose uptake of the diaphragm muscle was also decreased. Administration of alpha-tocopherol (600 mg/kg-1, i.m.) ameliorated the inhibitory effect of diabetes on the skeletal muscle and reversed the decrease in time (s) of the 50% decrease in the height of contraction of the indirect responses of the rat hemidiaphragm preparation. Additionally, alpha-tocopherol increased glucose uptake by diaphragm muscles towards control level.


CONCLUSIONS
Alpha-tocopherol supplementation probably protected against the inhibitory effect of oxidative stress observed in diabetes mellitus and contributed to improved contractility.
Haidara
Mohamed A
MA
Department of Physiology, College of Medicine, King Saud University, Riyadh, Saudi Arabia.
Ibrahim
Ibrahim M
IM
Al-Tuwaijri
Ali S
AS
Awadalla
Sitelbanat A
SA
Yaseen
Hanna
H
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology; D003964:Diaphragm / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D016166:Free Radical Scavengers / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism* / Q000503:physiopathology; D018384:Oxidative Stress / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D024502:alpha-Tocopherol / Q000494:pharmacology*
D016166:Free Radical Scavengers; D024502:alpha-Tocopherol; D005947:Glucose