Role of adipogenic and thermogenic genes in susceptibility or resistance to develop diet-induced obesity in rats

ABSTRACT

The aim of the present work was to assess whether changes in adipose tissue geneexpression related with adipogenesis and/or thermogenesis could be involved in themechanism conferring susceptibility or resistance to develop obesity in high-fat fedoutbreed rats. For this purpose, male Wistar rats were fed with standard laboratorydiet (control group) or high fat diet. After 15 days, two groups of rats with significantdifferences on body weight gain in response to the high fat diet were characterizedand identified as diet-induced obesity (DIO) and diet resistant (DR) rats. A significantincrease in visceral white adipose tissue (WAT) PPARã and aP2 (p<0.05)mRNA levels associated to a decrease in RARã expression (p<0.05) was observed inDIO rats, suggesting an increase of adipogenesis. Furthermore, our data showed amarked increase in brown adipose tissue (BAT) of UCP1 mRNA in DIO animals(p<0.01) (without affecting PGC-1á gene expression), whereas no changes werefound in WAT UCP2 gene expression. All these data suggest that the variationsfound in the expression pattern of PPARã, aP2 and RARã by high-fat diet could beinvolved, at least in part, in the differences in body weight gain and adiposityobserved between DR and DIO animals. The compensatory adaptations through theincrease in energy expenditure by changes on the expression levels of UCP1 seem notto be enough to avoid the obesity onset in the DIO group (AU)

RESUMEN

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