A high-fat diet combined with food deprivation increases food seeking and the expression of candidate biomarkers of addiction
A mouse model has been developed to study the effect of dietary fat combined with food deprivation periods on palatable food seeking and on the expression of three potential addiction biomarkers in the nucleus accumbens: fumarate hydratase (FH), ATP synthase subunit alpha (ATP5a1) and transketolase (TKT). Forty C57BL/6 J male mice, four-week old, were fed either with a high-fat (HF) diet or standard diet along the experiment. After 3 weeks of differential feeding, animals underwent a two-week training period of two daily sessions where visual cues were paired either to palatable food (chocolate cereals) or no food at all. This training was prolonged one more week with similar, one daily sessions preceded by 12 hours of food deprivation. A behavioural test was finally conducted where mice were confined for 30 minutes either in food unpaired compartments or in compartments previously paired with cereals, but now with empty food trays. Total activity during this behavioural test and serum corticosterone levels right after it were similar in all experimental groups. Mice tested in food-paired compartments showed a marked preference for the empty food tray that gradually disappeared in standard diet-fed individuals but persisted in HF-fed mice. HF-fed mice also overexpressed FH, ATP5a1 and TKT, which positively correlated with the persistence of preference for the empty food tray. It is suggested that HF diets combined with food deprivation may enhance food seeking behaviours while upregulating FH/ATP5a1/TKT, which are further envisaged as biomarkers of addiction.