Dietary walnut oil modulates liver steatosis in the obese Zucker rat.
OBJECTIVE
Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome. We aimed to clarify the impact of dietary walnut oil versus animal fat on hepatic steatosis, representing the initial step of multistage pathogenesis of NAFLD, in Zucker obese rats.


METHODS
Zucker lean ad libitum (a.l.), Zucker obese a.l. or Zucker obese pair fed (p.f.) to the lean received isocaloric diets containing 8% walnut oil (W8), W14 or 14% lard (L14) (n = 10/group). Body weight, clinical serology, liver weight, lipid content and fatty acid composition and hepatic lipid metabolism-related transcripts were evaluated.


RESULTS
Compared to lean, Zucker obese a.l. and p.f. showed hepatic triacylglyceride (TAG) accumulation. In Zucker obese p.f., W14 compared to W8 and L14 reduced liver lipids, TAG as well as hepatic omega-6 (n-6)/n-3 ratio and SCD activity index [(C18:0 + C18:1)/C18:0 ratio] paralleled by decreased lipoprotein lipase mRNA in obese p.f. and elevated microsomal triglyceride transfer protein mRNA in lean and obese. Further, W14 elevated the fasting blood TAG and reduced cholesterol levels in obese.


CONCLUSIONS
In our model, consumption of W14 inhibited hepatic lipid accumulation along with modulated hepatic gene expression implicated in hepatic fatty acid influx or lipoprotein assembly. These results provide first indication that dietary lipids from walnut oil are modulators of hepatic steatosis as the initial step of progressive NAFLD pathogenesis.
Department of Physiology and Biochemistry of Nutrition, Max Rubner-Institut, Haid-und-Neu-Str. 9, 76131, Karlsruhe, Germany.
Anja
A
Fink
Corinna E
CE
Rüfer
Julie
J
Le Grandois
Alexander
A
Roth
Dalal
D
Aoude-Werner
Eric
E
Marchioni
Achim
A
Bub
Stephan W
SW
Barth
D000818:Animals; D002352:Carrier Proteins / Q000235:genetics; D004032:Diet; D004041:Dietary Fats; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage*; D005227:Fatty Acids / Q000032:analysis; D005234:Fatty Liver / Q000150:complications / Q000378:metabolism*; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D031324:Juglans; D050356:Lipid Metabolism / Q000187:drug effects / Q000235:genetics; D008055:Lipids / Q000032:analysis / Q000097:blood; D008071:Lipoprotein Lipase / Q000235:genetics; D008099:Liver / Q000737:chemistry / Q000378:metabolism; D024821:Metabolic Syndrome / Q000150:complications; D065626:Non-alcoholic Fatty Liver Disease; D009765:Obesity / Q000150:complications*; D010938:Plant Oils / Q000008:administration & dosage* / Q000737:chemistry; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011924:Rats, Zucker; D014280:Triglycerides / Q000032:analysis / Q000378:metabolism
D002352:Carrier Proteins; D004041:Dietary Fats; D004042:Dietary Fats, Unsaturated; D005227:Fatty Acids; D008055:Lipids; D010938:Plant Oils; D012333:RNA, Messenger; D014280:Triglycerides; C106092:microsomal triglyceride transfer protein; D008071:Lipoprotein Lipase; C029310:lard