Fig. 4.

Uncoupling protein-2 (UCP2) mediates normal lifespan in mice. A: analysis of Kaplan-Meier survival curves indicates that ucp2^−/− mice have a significantly shorter survival age compared with UCP2 wild-type (WT) mice (n = 9 for both groups, P < 0.0001, log-rank analysis of Kaplan-Meier survival curves). B: human UCP2 (hUCP2) Tg mice (n = 14) do not have an increased survival age compared with hUCP2 WT mice, although time to first death was delayed in hUCP2 Tg mice (n = 19). C: double knockout of superoxide dismutase-2 (sod2) and UCP2 (n = 7) significantly decreased survival age compared with sod2^−/− mice with UCP2 (n = 30, P < 0.0001). No significant spontaneous death events were recorded in sod2 +/− or +/+ mice with or without UCP2. D: presence of hUCP2 Tg in sod2^−/− mice significantly increases survival age relative to sod2^−/− mice without hUCP2. No significant death events were recorded in other genotypes.