Figure 4.

PTH and antioxidants reduce the age-related increase in oxidative stress and osteoblast apoptosis. Six month old female C57BL/6 mice were injected daily with saline (−). 24 month old mice were injected daily with saline (−), 100 ng/g PTH(1–34) or 200 μg/g pegylated catalase (cat), or fed a diet containing 100 mg/kg NAC, or given both NAC and catalase (NAC/cat) for 28 days (N=9–12/group). ROS (A) and glutathione (GSH) (B) were quantified in cells flushed from femoral bone marrow (AFU, arbitrary fluorescence units) (N=4/group). (C) Phosphorylated p66^Shc in vertebral lysates. Two blots were performed to accommodate all treatment groups. Each lane represents a vertebral lysate from a single animal. (D) Alox15 mRNA in vertebral extracts (N=9–12/group). (E) The prevalence of osteoblast apoptosis was determined in vertebral bone sections (N=5 per group). * p<0.05 vs. 24 month old vehicle control by one-way ANOVA. (F) Expression of Wnt target genes in vertebral bone (N=9–12/group). The data shown represents the fold decrease (red) in transcript expression from 6 month to 24 months of age; and the fold increase (green) in expression in 26 month old mice given PTH or antioxidants compared to vehicle controls. Expression levels were normalized to GAPDH. Only statistically significant (p<0.05) changes are shown, as determined by one-way ANOVA for each transcript.