[Purpose] This study examined how exercise capacity and the oxidative stress regulation system are affected by different amounts of dietary Ubiquinol (reduced form of coenzyme Q10, H2CoQ10: QH) over the long term. [Subjects and Methods] Twenty-three senescence-accelerated mouse P1 (SAMP1) mice were randomly divided into two groups: one consuming a relatively high amount of QH (300 mg/kg; Group A) and the other a relatively low amount (30 mg/kg, Group B). Food and tap water were provided ad libitum. Both groups were made to run on a treadmill until exhaustion, and total running duration was measured. For the oxidative stress regulation system, the d-ROM test value (degree of oxidative stress) and BAP test value (antioxidant potential) were measured in a resting state, and then the BAP/d-ROM ratio (B/R ratio) was calculated. The values of plasma QH and plasma ubiquinone (plasma oxidized form of CoQ10) were also measured, and the reduced ratio was calculated. Measurements were taken 3 times: at the start of the study when the animals were 39 weeks old (baseline), after consumption of QH for 7 months (7 mo), and after consumption of QH for 10 months (10 mo). [Results] The senescence score at 10 mo was significantly lower in Group A. Comparison of the mean percentage change in running time showed a difference of 15.1% between the 2 groups. At 10 mo, the d-ROM test value was significantly increased and the B/R ratio was significantly decreased in Group B. Significant increases in the plasma QH value and reduced ratio were seen in Group A. [Conclusion] Group A showed a greater decrease in the d-ROM test and increase in the reduced ratio than Group B. Thus, a dose-dependent effect of QH consumption was demonstrated.
Keywords: Exercise capacity; Mice; Oxidative stress regulation system; Ubiquinol.