26.8. Alpha lipoic acid supplementation can induce antioxidant protection in skeletal muscle

Public examination of a doctoral dissertation in the field of physiology

Doctoral candidate: MSc Susanna Kinnunen

Time and venue: 26.8.2011 at 12 noon, Mediteknia Auditorium, Kuopio Campus

The doctoral dissertation of MSc Susanna Kinnunen shows that alpha lipoic acid supplementation can enhance cellular protection against exercise-induced oxidative stress and muscle damage in horses.

The relationship between exercise and oxidative insults is well demonstrated and has been implicated in muscle damage and decreased muscle performance. During heavy physical exercise the oxygen flux to active skeletal muscle increases several folds, which enhances production of reactive oxygen species (ROS). Studies examining racehorses in training have shown that the most common reasons for retraction of the trotters from racecourses are musculoskeletal injuries. This may be in part due to an exercise-induced increase in ROS production.

This study presents an overview of ROS-related insults and tissue protection mechanisms in skeletal muscle after controlled trials on a high-speed treadmill in horses. The antioxidant effects of a natural thiol compound and redox-modulator, α-lipoic acid (LA), were also studied. In addition to the acute effects of exercise, important data during the recovery period of up to 48 hours were also gained.

One bout of acute, submaximal exercise increased the concentrations of oxidised protein and lipid products as well as the antioxidant capacity in plasma and in muscle. However, submaximal exercise had no effect on muscle stress protein levels. LA supplementation reduced the rate of free radical formation in skeletal muscle, activated stress protein induction and simultaneously decreased the concentrations of oxidised protein and lipid peroxidation products. LA appeared also to decrease ROS formation within muscle cells.

Based on this study, it can be concluded that trotters are prone to exercise-induced oxidative stress. However, LA supplementation may be used to improve performance by decreasing the formation of free radicals and by increasing the rate of stress protein expression and inducing antioxidant protection in horse skeletal muscle.

A broad-based knowledge in exercise-induced oxidative insults will improve our understanding of oxygen-related insults and their management. The results of this thesis support previous studies that micronutrient supplementation can increase the total antioxidant status and enhance cellular protection against exercise-induced oxidative stress and muscle damage. However, it should be kept in mind that prolonged mega-dose supplementation of micronutrients may attenuate the normal exercise-related responses of tissues and blunt training-induced adaptations.

The doctoral dissertation of Master of Science Susanna Kinnunen, entitled Oxidative stress in skeletal muscle after acute exercise, will be examined at the Faculty of Health Sciences. The opponent in the public examination will be Professor Heikki Kainulainen of the University of Jyväskylä and the custos will be Professor (Emer.) Osmo Hänninen of the University of Eastern Finland.

Photo available for download at http://www.uef.fi/uef/vaitoskuvat

For further information, please contact: MSc Susanna Kinnunen, University of Eastern Finland,Institute of Biomedicine, GSM +358 40 7177211, susanna.kinnunen@uef.fi

Publishing year: 2011

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