Diet restriction in mice causes differential tissue responses in total reducing power and antioxidant compounds

Background: Diet restriction (DR) has been shown to extend the life spans of various laboratory animals, the mechanism may involve a decrease in oxidative stress. When determining if the total tissue defense has been altered, it is important to observe the overall direct antioxidant capacity, which consists of low molecular weight antioxidants (LMWA) and enzymes. Aim: To determine DR induced changes in total reducing power and overall direct antioxidant capacity of various mouse tissues. Methods: Young female Sabra mice were fed a 60 % food restricted diet for 40 days (DR group). Organs of the DR group and of ad libitum (AL) fed controls were then dissected and examined. A cyclic voltammetry method was used to quantify the total reducing power, which correlates with the overall LMWA activity. Specific LMWA were identified by HPLC-ECD. Superoxide dismutase activity and H₂O₂ degrading ability were measured in order to include the enzymatic antioxidant component. Results: Short-term DR caused alterations in the total reducing power of various mouse tissues, indicating changes in the total scavenging ability of these tissues. Overall direct antioxidant capacity of heart, kidney and muscle was enhanced; liver and small intestine deteriorated; brain did not differ between DR and AL groups; lung and spleen exhibited a mixed response. Conclusions: We have shown for the first time that DR causes changes in the total reducing power of different mouse tissues, thus, affecting the overall direct antioxidant capacity. These findings support the suggestion that there may be a biological regulation of the antioxidant system.