Background and objective: Diabetes mellitus affects skeletal muscle and free radicals
are probably implicated in the manifestations of diabetes complications. Antioxidants
have been proposed as therapeutic strategies to protect against diabetes-induced
muscle dysfunction. The present study aimed to investigate and compare the effects of
vitamin E or selenium on fast twitch gastrocnemius muscle of streptozotocine induced
type 2 diabetic rats via recording twitch tension, time to peak tension, half relaxation
time and peak tetanic tension and determination of muscle malondialdehyde and
glutathione peroxidase as markers for oxidant status, specially, for our knowledge, the
effects of vitamin E or selenium on contractile parameters of diabetic fast twitch
muscles have not been previously investigated.
Material and methods: 24 male rats of local breed were randomly divided into 4
groups (n=6), control group, diabetic group in which diabetes was induced by i.p.
injection of streptozotocin 40 mg.kg-1 , vitamin E supplemented diabetic group (600
mg.kg-1 daily) and selenium supplemented diabetic group (5 micromole.kg-1 daily) for 4
weeks starting 3 days after induction of diabetes.
Results: Diabetes significantly reduced twitch tension and peak tetanic tension of
gastrocnemius muscle with no significant change in time to peak tension and half
relaxation time. Vitamin E or selenium administration to diabetic rats reversed the
oxidative imbalance and improved muscle contractile status with more significant
effect in selenium supplemented rats.
Conclusion: Vitamin E or selenium can protect against the alterations in fast twitch
muscle properties associated with diabetes.