Dietary restriction reduces blood lipids and ameliorates liver function of mice with hyperlipidemia

Dietary restriction (DR) can delay senescence, prolong lifespan of mammals and improve their learning-memory activity. The purpose of the study was to explore the effects of DR on hypolipidemic action and liver function of mice with hyperlipidemia. To investigate these effects, hyperlipidemia mouse models were established with high-fat diet (HFD) (34% of energy), then randomly divided into HFD group, DR30% group and DR50% group. Mice in DR30% and DR50% group were respectively supplied with HFD as much as about 70% and 50% of the consumption of HFD in the mice of HFD group. Rats in control group were fed routinely. After DR for 5 weeks, the average body weight, liver weight, liver index, serum lipids and glucose levels in both DR groups decreased significantly as compared with the HFD group (P < 0.05 or P < 0.01), so did alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) levels and the ratio of LDL-C/HDL-C in the DR50% group (P < 0.05 or P < 0.01). Histopathology examination of liver tissues further proved ameliorative effect of DR on liver function. Western blotting showed that DR significantly increased the expression of silent mating type information regulation 2 homolog 1 (SIRT1) in liver and adipose, while notably decreased the expression of peroxisome proliferators-activated receptors-gamma (PPAR gamma) in adipose (P < 0.05 or P < 0.01). The increase of SIRT1 and decrease of PPAR gamma may be a mechanism by which DR reduces blood lipids and ameliorates liver function.