Figure 7 of Al-Hussaini, Mol Vis 2008; 14:1784-1791.

Figure 7. The number of BrdU positive cells in the RPE following multiple pulses at progressive times. BrdU was given as a single pulse (50µg/kg) or as multiple pulses in 2 month old DA rats. For comparison animals were given 4 injections at 3 h intervals and euthanized 3 h later. Similar experiments were undertaken at 12 h intervals, with single pulse and euthanized 12 h later compared with 4 pulses separated by 12 h each and euthanized 12 h after the last pulse. There was no statistically significant increase in labeled cells following multiple injections compared with single injections. However, when BrdU was pulsed at 24 h intervals over 5 days, there was a significant increase in the number of RPE labeled cells compared with labeling in any of the other groups (ANOVA, p<0.0001. Dunnett’s Multiple Comparison Test p<0.001). Hence the RPE population is proliferating, but with a cell cycle rate of approximately 5 days.