The Influence of dietary lipid composition on skeletal muscle mitochondria from mice following eight months of calorie restriction

Abstract

Calorie restriction (CR) has been shown to decrease reactive oxygen species (ROS) production, attenuate oxidative damage and retard aging in a variety of species. CR has also been observed to alter membrane composition towards saturation. This has led to a theory that changes in membrane saturation are central to the actions of CR. As a first step towards testing this theory, C57BL/6 mice were assigned to 4 dietary groups (control and 3 CR groups) and fed AIN‐93G diets at 95% (control) or 60% (CR) of ad libitum. To manipulate membrane composition, the primary dietary fats for the CR groups were soybean oil (also used in the control diet), fish oil or lard. The diets were fed for 8 months and then mitochondria from hindlimb skeletal muscle were isolated for measures of mitochondrial lipid composition, proton leak, and H2O2 production. Changes in mitochondrial phospholipid fatty acids in the CR mice reflected the dietary lipid sources. The capacity of mitochondrial complex III to produce ROS was decreased in the CR lard compared to either the CR soybean or fish oil groups. However, diet lipid composition did not alter proton leak kinetics between the CR groups. The results of this study indicate that mitochondrial lipid composition can influence ROS production in the CR regimens. It remains to be determined if lard or other mixtures of dietary oils can maximize the CR‐induced decrease in ROS production. (Supported by NIH RO1 AG028125)