Diet and feeding condition induced gene expression in rat peripheral blood mononuclear cells

This study analyzed gene expression of rat peripheral blood mononuclear cells by microarray analysis following different feeding conditions (ad libitum feeding, fasting and refeeding) in normoweight (control) and in diet-induced obese rats (cafeteria rats). The aim of this study was to identify genes and biological pathways that were altered by feeding conditions in normoweight and diet-induced obese rats. Keywords: Dietary treatment, analysis of feeding conditions Gene expression of Peripheral blood mononuclear cells (PBMC) was assesed by whole genome microarray analysis. Normoweight and diet-induced obese (cafeteria-fed) Wistar rats were submitted to ad libitum feeding, fasting and re-feeding feed conditions. Two-month-old male Wistar rats (n=29) were assigned into two dietary groups for 4 months: the control group (n=14) was fed with a standard chow diet, whereas the second group (cafeteria group, n=15) was fed with a fat-rich hypercaloric cafeteria diet in addition to the standard chow. At 6 months of age each group of rats was distributed in three subgroups submitted to different feeding conditions (n=4 or 5 for each condition): feeding (animals provided with ad libitum access to diet), fasting (animals deprived of food for 14 h) and re-feeding (fasted animals with a posterior free access to diet for 6 h). For PBMC isolation, blood samples were collected from the safena vein, using heparine in NaCl (0.9%) as anticoagulant; immediately after the blood collection, PBMC were isolated by Ficoll gradient separation, and RNA was extracted. One sample in the control group was excluded because of low amount of RNA. Gene expression changes were assessed using the Agilent rat whole genome microarray (G4131F Agilent Technologies).