Ubiquitous overexpression of CuZn superoxide dismutase does not extendlife span in mice

Abstract

Oxidative damage has been implicated in the aging process and in anumber of degenerative diseases. To investigate the role of oxygen radicalsin the aging process in mammals, the life spans of transgenic mice on aCD-1 background expressing increased levels of CuZn superoxide dismutase(CuZnSOD), the enzyme that metabolizes superoxide radicals, weredetermined. Homozygous transgenic mice with a two- to five-fold elevationof CuZnSOD in various tissues showed a slight reduction of life span,whereas hemizygous mice with a 15- to 3-fold increase of CuZnSOD showed nodifference in life span from that of the nontransgenic littermate controls.The results suggest that constitutive and ubiquitous overexpression ofCuZnSOD alone is not sufficient to extend the life spans of transgenicmice.