Lipid metabolism in adipose tissue and liver from diet-induced obese rats: a comparison between Wistar and Sprague-Dawley strains
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Some researchers have proposed important variations in adipose tissue among different strains of rats and mice in response to a high-caloric (hc) diet, but data concerning the mechanisms underlying these differences are scarce. The aim of the present research was to characterize different aspects of triacylglycerol (TG) metabolism and clock genes between Sprague-Dawley and Wistar rats. For this purpose, 16 male Sprague-Dawley and 16 male Wistar rats were divided into four experimental groups (n = 8) and fed either a normal-caloric (nc) diet or a hc diet for 6 weeks. After sacrifice, liver and epididymal, perirenal, mesenteric, and subcutaneous adipose tissue depots were dissected, weighed and immediately frozen. Liver TG content was quantified, RNA extracted for gene expression analysis and fatty acid synthase enzyme activity measured. Two-way ANOVA and Student’s t test were used to perform the statistical analyses. Under hc feeding conditions, Wistar rats were more prone to fat accumulation in adipose tissue, especially in the epididymal fat depot, due to their increased lipogenesis and fatty acid uptake. By contrast, both strains of rats showed similarly fatty livers after hc feeding. Peripheral clock machinery seems to be a potential explanatory mechanism for Wistar and Sprague-Dawley strain differences. In conclusion, Wistar strain seems to be the best choice as animal model in dietary-induced obesity studies.
KeywordsHigh-caloric feeding Obesity Strain Wistar Sprague-Dawley Rats
The technical assistance of Asier Leniz in RNA isolation and quality assessment is gratefully acknowledged.
This study was supported by grants from the Instituto de Salud Carlos III (CIBERObn), Government of the Basque Country (IT-572-13) and University of the Basque Country (UPV/EHU) (ELDUNANOTEK UFI11/32). Itziar Eseberri is a recipient of a doctoral fellowship from the University of the Basque Country. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Compliance with ethical standards
All animal experimental protocols were reviewed and approved by the ethics committee on animal welfare of our institution (Comité Ético de Experimentación Animal de la Universidad del País Vasco, CEEA-UPV/EHU).
Conflict of interest
The authors declare that there are no conflicts of interest.
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