Reductions in cellular oxygen consumption (V̇o2) and reactive oxygen species (ROS) production have been proposed as mechanisms underlying the anti-aging effects of calorie restriction (CR). Mitochondria are a cell's greatest “sink” for oxygen and also its primary source of ROS. The mitochondrial proton leak pathway is responsible for 20–30% of V̇o2 in resting cells. We hypothesized that CR leads to decreased proton leak with consequential decreases in V̇o2, ROS production, and cellular damage. Here, we report the effects of short-term (2-wk, 2-mo) and medium-term (6-mo) CR (40%) on rat muscle mitochondrial proton leak, ROS production, and whole animal V̇o2. Whole body V̇o2 decreased with CR at all time points, whereas mass-adjusted V̇o2 was normal until the 6-mo time point, when it was 40% lower in CR compared with control rats. At all time points, maximal leak-dependent V̇o2 was lower in CR rats compared with controls. Proton leak kinetics indicated that mechanisms of adaptation to CR were different between short- and medium-term treatments, with the former leading to decreases in protonmotive force (Δp) and state 4 V̇o2 and the latter to increases in Δp and decreases in state 4 V̇o2. Results from metabolic control analyses of oxidative phosphorylation are consistent with the idea that short- and medium-term responses are distinct. Mitochondrial H2O2 production was lower in all three CR groups compared with controls. Overall, this study details the rapid effects of short- and medium-term CR on proton leak, ROS production, and metabolic control of oxidative phosphorylation. Results indicate that a reduction in mitochondrial V̇o2 and ROS production may be a mechanism for the actions of CR.
Reactive oxygen species trigger NF-κB-mediated NLRP3 inflammasome activation involvement in low-dose CdTe QDs exposure-induced hepatotoxicity
