Heart lipid accumulation in obese non-diabetic rats: effect of weight loss.
OBJECTIVE
The aim of this study was to investigate lipid content and expression of genes involved in lipid metabolism, in lean and obese non-diabetic rats and in obese rats undergoing food restriction and weight loss.


RESULTS
We studied lean and genetically obese Zucker rats (fa/fa). Another group of obese rats were food restricted to lose 20% of initial body weight. We measured expression of genes involved in lipid oxidation and synthesis. Tissue triglyceride content, cell apoptosis and tissue fibrosis were also evaluated. The hearts of obese rats have higher triglyceride content compared to lean controls despite an increased expression of genes involved in fatty acid oxidation (PPAR alpha, PGC-1 alpha, CPT-I, ACO, UCP3). No differences were found in apoptosis and tissue fibrosis between the two phenotypes. Weight loss resulted in a significant reduction in heart lipid content, while the expression of genes involved in fatty acid oxidation remained elevated.


CONCLUSIONS
In contrast to data reported in diabetic rats, pathways of lipid oxidation are increased rather than decreased in insulin-resistant obese rats. Food restriction reduced heart triglyceride content while lipid-oxidizing genes remained elevated, probably as a consequence of lipid oversupply coming from the endogenous source.
Pagano
Claudio
C
Endocrine Metabolic Unit, Department of Medical and Surgical Sciences, University of Padova, via Ospedale 105, 35100 Padova, Italy. claudio.pagano@unipd.it
Calcagno
Alessandra
A
Granzotto
Marnie
M
Calabrese
Fiorella
F
Thiene
Gaetano
G
Federspil
Giovanni
G
Vettor
Roberto
R
D000818:Animals; D017209:Apoptosis; D004038:Diet, Reducing; D005784:Gene Amplification; D005786:Gene Expression Regulation; D050356:Lipid Metabolism / Q000235:genetics*; D008297:Male; D009206:Myocardium / Q000737:chemistry / Q000378:metabolism*; D009765:Obesity / Q000178:diet therapy / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D011897:Random Allocation; D051381:Rats; D011924:Rats, Zucker; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013851:Thinness / Q000235:genetics / Q000378:metabolism*; D014280:Triglycerides / Q000032:analysis / Q000378:metabolism*; D015431:Weight Loss / Q000502:physiology*
D014280:Triglycerides