Proteomic analysis for protein carbonyl as an indicator of oxidative damage in senescence-accelerated mice.

The senescence-accelerated prone mouse strain 8 (SAMP8) exhibits a remarkable age-accelerated deterioration in learning and memory. In this study, we identified carbonyl modification, a marker of protein oxidation, in liver and brain of SAMP8 from peptide mass fingerprints using MALDI-TOF mass spectrometry in combination with LC-MS/MS analysis. Carbonyl modification of Cu,Zn-superoxide dismutase (Cu,Zn-SOD) in liver at 3 month and hippocampal cholinergic neurostimulating peptide precursor protein (HCNP-pp) in brain at 9 month were higher in SAMP8 compared with control SAMR1. We demonstrated carbonyl modification of purified Cu,Zn-SOD increased by the reaction with H2O2. Therefore, progressive accumulation of oxidative damage to Cu,Zn-SOD, may cause dysfunction of defense systems against oxidative stress in SAMP8 with a higher oxidative states, leading to acceleration of aging. Furthermore, carbonyl modification of HCNP-pp may be involved in pathophysiological alterations associated with deterioration in the learning and memory in the brain seen in SAMP8.