Figure 3. BrdU labeling index (BLI) (mean ± SEM).
Mice received one or more injections of BrdU at age 8, 9, 10–11, 12–14, 15–21, 22–28, or 29–35 days to label cells in S-phase. BrdU labeling was evaluated in tubular epithelial cells in the renal cortex (A, P < 0.001 ANOVA) and in hepatocytes (B, P < 0.001 ANOVA). The BLI was calculated by dividing the number of BrdU-labeled nuclei by the total number of nuclei. For tubular epithelial cells, a significant decrease was present only after 14 days (P < 0.05 for all pairwise comparisons between each of the first 4 time points and each of the last 3 time points).