Effects of high‐fat diet intake and endurance training on CLOCK gene in rat skeletal muscle

Abstract

【Objective】Excess caloric intake is associated with the development of obesity. A number of recent studies suggest that attenuation of CLOCK gene amplitude by high‐fat diet causes obesity. Normalizing to the CLOCK gene amplitude can be considered to contribute for the prevention of obesity. Also endurance training has the effect for prevention of obesity, but influence on the disorder of CLOCK gene by high‐fat diet intake is not clear. In the present study, we investigated the effects of high‐fat diet intake and endurance training on CLOCK gene in rat skeletal muscle.
 【Methods】Adult male Wistar rats (∼260 g) were used. Animals were randomly divided into three groups; control diet (CON), high‐fat diet (HF) and high‐fat diet+ training (HF+Tr). The CON animals were received a standard diet. HF and HF+Tr animals were received high‐fat diet containing of 62% fat as calories. All animals were feeding two times per day. The rats of each group were provided equal food volume per day for six weeks. HF+Tr animals were exercised on treadmill (90 min/day and 5 days a week). The mRNA expression of CLOCK genes (Bmal1, Clock, and Per2 ) in skeletal muscle were tested at four points (ZT2, ZT8, ZT14 and ZT20) .
 【Results and Conclusion】 The body weight of HF was heavy significantly compared with CON and HF+Tr. In skeletal muscle Bmal1 and Per2 gene expressions were not affected by high‐fat diet. On the other hand, the amplitude of Clock expression was attenuated in the HF and HF+Tr. In the present study, we consider the attenuation of Clock expression in skeletal muscle might be caused by lipid metabolism abnormality. Therefore, high‐fat diet intake was suggested to become obesity.