Effect of caloric restriction on liver function in young and old ApoE/LDLr-/- mice

Caloric restriction (CR) leads to decrease metabolic intensity, which results in a reduction of oxygen consumption and the amount of free radicals. This can affect the function of the liver. Studies show that caloric restriction does not alter or significantly increase the enzyme activity associated with gluconeogenesis, but the effect was different according to the age of the model animals.

The aim of the study was to determine the effect of caloric restriction on liver function in young and old ApoE/ LDLr-/- mice.

Dietary experiments were performed on 2 and 5 month old male ApoE/LDLr-/- mice. Animals were divided into 3 experimental groups (n=6) and fed AIN’93G diet for 8 and 5 weeks, respectively. Control animals were fed ad libitum (AL) and housed in a colony cages. These animals were checked for dietary intake. The second group were also fed ad libitum but the animals were kept individually in cages (stress AL- sAL). Similarly to sAL group, the animals from the CR group were kept individually but received a 30% less diet compared to AL group. At the end of the experiment animals were euthanized and the blood, liver and adipose tissue have been collected. Alanine aminotransferase (ALT) as well as aspartate aminotransferase (AST) were measured in plasma. Fatty acid profile was evaluated (relative %) in adipose tissue (GC-MS). Liver’s stetosis was assessed. Results were analyzed statistically (ANOVA, STATISTICA v.10.0).

CR ApoE/LDLr-/- mice showed significantly lower body weight compared to animals, both AL and sAL. There were no significant differences between ALT and AST in both younger and older animals. However, negative tendencies were more pronounced in younger animals. In young animals CR significantly increased liver weight compared to AL (4.14 vs 3.73g/100g). In adipose tissue fatty acid profile differed in CR mice compared to control in young animals.

Caloric restriction did not affect liver enzymes in mice. Caloric restriction showed similar but not identical metabolic activity in young and old mice.