PGC1α isoforms expression in skeletal muscle of trained and/or CLA supplemented mice

Abstract

It has been reported that Conjugated Linoleic Acid (CLA) improves muscle hypertrophy [1], steroidogenesis [2], physical activity, and endurance capacity in mice [3]. Recently, it has been reported that endurance exercise increased the expression of PGC1 isoforms in murine skeletal muscle [4]. The aim of the present study was to quantify the expression of any of the peroxi- some proliferator-activated receptor γ coactivator 1α (PGC1α) isoforms in gastrocnemius and plantaris muscles of trained and/or CLA supplemented mice. Mice were randomly divided in four groups: placebo sedentary, CLA sedentary, placebo trained, or CLA trained. The CLA groups were gavaged with 35μl per day of Tonalin® FFA 80 food supplement containing CLA throughout the 6-week experimental period, whereas the placebo groups were gavaged with 35μl sunflower oil each day. Each administered dose of CLA corresponded to approximately 0.7g/kg or 0.5%, of the dietary daily intake. Trained groups ran 5days per week on a Rota-Rod for 6 weeks at increasing speeds and durations. Mice were sacrificed by cervical dislocation and hind limb posterior muscle groups were dissected and used for histological and molecular anal- yses. Endurance training increased the expression of PGC1α isoforms (tot, α1, α2, and α3), but CLA supplementation did not increased PGC1α isoforms expression in trained and/or seden- tary mice. In the plantaris muscle, CLA supplementation induced a fibre-type-specific hypertro- phy of type IIx muscle fibres.