Effects of fatty acids on skeletal muscle cell differentiation in vitro.
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.
Hurley
Matthew S
MS
Division of Nutritional Sciences, University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough, UK.
Flux
Claire
C
Salter
Andrew M
AM
Brameld
John M
JM
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D002478:Cells, Cultured; D003402:Creatine Kinase / Q000032:analysis; D004247:DNA / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D005227:Fatty Acids / Q000494:pharmacology*; D019787:Linoleic Acid / Q000494:pharmacology; D044243:Linoleic Acids, Conjugated / Q000494:pharmacology; D018482:Muscle, Skeletal / Q000166:cytology*; D032446:Myoblasts / Q000166:cytology / Q000187:drug effects*; D019301:Oleic Acid / Q000494:pharmacology; D019308:Palmitic Acid / Q000494:pharmacology; D047492:Peroxisome Proliferator-Activated Receptors / Q000819:agonists; D020025:Peroxisome Proliferators / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D051381:Rats; D000077154:Rosiglitazone; D045162:Thiazolidinediones / Q000494:pharmacology
D005227:Fatty Acids; D044243:Linoleic Acids, Conjugated; D047492:Peroxisome Proliferator-Activated Receptors; D020025:Peroxisome Proliferators; D011743:Pyrimidines; D045162:Thiazolidinediones; D000077154:Rosiglitazone; D019301:Oleic Acid; D019308:Palmitic Acid; C006253:pirinixic acid; D004247:DNA; D019787:Linoleic Acid; D003402:Creatine Kinase