Research Paper Volume 1, Issue 9 pp 784—802

Figure 11. The effects of H ₂O₂ on the phosphorylation of p38 MAPK catalytic site in wild-type and Ames dwarf mouse fibroblasts. The fibroblasts from young (4-6mos) and old (21-24 mos) wild type and dwarf mice show an attenuated induction of phosphorylation of the p38 MAPK catalytic site amino acid residues in response to H₂O₂. The bar graphs and western blot analyses below each bar graph show the pool levels and levels of phosphorylation of the p38 MAPK catalytic site amino acid residues (P-Thr¹⁸⁰/P-Tyr¹⁸²) in (A) young wild-type and dwarf fibroblasts (4-6 mos) and (B) in old wild-type and dwarf fibroblasts (21-24 mos) after treatment with varying concentrations of H₂O₂ (0.2 to 1.0 mM). The p38 MAPK activities of both young and old wild type fibroblasts continue to rise exponentially up to the highest level of H₂O₂ (1 mM) treatment. The fibroblasts from young and old dwarf mice show similar levels of resistance to increasing levels of H₂O₂ suggesting that resistance to this ROS species does not change with age in these fibroblasts. n=3, * p<0.05 between wild-type vs. dwarf.