Effects of fatty acids on skeletal muscle cell differentiation in vitro

Division of Nutritional Sciences, University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough, UK.
British Journal Of Nutrition (Impact Factor: 3.45). 04/2006; 95(3):623-30. DOI: 10.1079/BJN20051711
Source: PubMed


Previous studies have shown stimulatory effects of linoleic acid (LA, C18:2) on differentiation of rat muscle cells in culture (Allen et al. 1985), but there appears to be little investigation of the effects of other fatty acids. The present study therefore compared the effects of different fatty acids on muscle cell differentiation in vitro. L6 myoblasts were cultured (Dulbecco's Modified Eagles Medium + 10 % fetal calf serum) in six-well plates until 80 % confluent (day 0). Cells were then either harvested or the medium switched to differentiation medium (Dulbecco's Modified Eagles Medium+2 % horse serum), supplemented with fatty acid or drug treatments. Cells were harvested on days 0-5 and assayed for creatine kinase (CK), protein and DNA contents, to give a measure of differentiation (CK/DNA). Initial studies indicated a stimulatory effect of the cis9,trans11 (c9,t11) isomer of conjugated linoleic acid (CLA) relative to control. By contrast, the trans10,cis12 (t10,c12) isomer of CLA inhibited differentiation. Further experiments indicated that inhibition of differentiation by the t10,c12 CLA isomer was dose-dependent (up to 200 microm) and may be via increased cell proliferation. LA and c9,t11 CLA stimulated differentiation at low concentrations (up to 50 microm), but inhibited differentiation at high concentrations (200 microm). In contrast, oleic acid stimulated differentiation at all concentrations, whereas the saturated fatty acid, palmitic acid, had no effect. The mechanism appeared not to involve either peroxisome proliferator-activated receptors alpha or gamma. The data suggest that only unsaturated fatty acids have an effect and the presence or absence of a cis-9 double bond may be important.

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    • "Absorption at 340 nm was measured at 30 8C every 5 min over a 30-min period. DNA content (mg/well) of the thawed cell lysate was measured using a fluorescence plate reader assay adapted from Rago et al. (Rago et al. 1990, Hurley et al. 2006). Protein content (mg/well) was measured via the Lowry method (Lowry et al. 1951) adapted for 96-well plate format. "
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    • "Specific nutrients. Due to the effects of maternal undernutrition on muscle cell proliferation/differentiation observed in the various in vivo studies, Brameld and co-workers have also investigated direct effects of nutrients on muscle differentiation in vitro (Hurley et al., 2006). They found that a number of unsaturated fatty acids (both poly-and mono-unsaturated) altered differentiation of L6 muscle cells, with no effect of palmitic acid, the only saturated fatty acid studied. "
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