Refeeding abolishes beneficial effects of severe caloric restriction from birth on adipose tissue and glucose homeostasis of adult rats.

Abstract Caloric restriction (CR) is an important intervention to reduce adiposity and improve glucose homeostasis. Recently we have found that in rats a severe caloric restriction (SCR) since birth up to adult age promotes positive effects on cardiometabolic risk factors and heart. Here, we investigated the effects of this new model of SCR on adipose tissue and glucose homeostasis of rats. Also, we evaluated the effects of refeeding. From birth to 90 days of age rats were divided into ad libitum (AL) group, which had free access to food, and CR50 group, which food was limited to 50% of that consumed by AL. From this moment, half of the CR50 animals had free access to food, called the refeeding group CR50-R, and the another half continued 50% restricted for an additional period of 90 days. Food intake was assessed daily and body weight weekly. In the last week of the SCR/refeeding protocol, oral glucose and intraperitoneal insulin tolerance tests were performed. Thereafter, rats were euthanized, visceral fat was collected and used for histological and western blot analysis. SCR since birth up to the adult life promoted a large decrease in visceral adiposity, improvement in glucose/insulin tolerance and up regulation of adipose PCNA, SIRT1, PPAR-y and adiponectin. Refeeding abolished all these effects. SCR from birth to adult age promoted beneficial effects on adipose tissue/glucose homeostasis and refeeding abolished these effects.