Characterization of survival and phenotype throughout the life...

In the present investigation we describe the life span characteristics and phenotypic traits of ad libitum-fed mice that overexpress UCP2/3 (Positive-TG), their non-overexpressing littermates (Negative-TG), mice that do not expression UCP2 (UCP2KO) or UCP3 (UCP3KO), and wild-type C57BL/6J mice (WT-Control). We also included a group of C57BL/6J mice calorie-restricted to 70% of ad libitum-fed mice in order to test partially the hypothesis that UCPs contribute to the life extension properties of CR. Mean survival was slightly, but significantly, greater in Positive-TG, than that observed in Negative-TG or WT-Control; mean life span did not significantly differ from that of the UCP3KO mice. Maximal life span did not differ among the ad libitum-fed groups. Genotype did not significantly affect body weight, food intake, or the type of pathology at time of death. Calorie restriction increased significantly mean and maximal life span, and the expression of UCP2 and UCP3. The lack of difference in maximal life spans among the Positive-TG, Negative-TG, and UCP3KO suggests that UCP3 does not significantly affect longevity in mice.