Table 1.

BrdUrd labelling of LRCS

(a) 6 week old 3HTdR labelled animals (BrdUrd at 12 weeks)
Time after BrdUrd3HTdR LRC peak LI%BrdUrd peak LI%Double-labelled Peak LI%
40 minutes16.0±0.796.8±1.511.8±4.0
2 days11.8±1.790.3±6.66.3±2.4
3 days16.795.8±4.10.0
4 days14.6±2.148.6±14.70.0
5 days12.547.9±12.90.0
6 days16.731.9±8.90.0
7 days16.712.5*0.0
8 days11.1±1.72.8±2.80.0
(b) 8Gy 3HTdR-labelled animals (BrdUrd at 8 days)
Time after BrdUrd3HTdR LRC peak LI%BrdUrd peak LI%Double-labelled Peak LI%
40 minutes11.7±2.799.4±0.611.1±3.2
2 days11.5±2.993.1±0.82.8±2.8
3 days14.6±2.193.8±6.30.0
4 days22.2±5.657.4±9.30.0
6 days16.713.9±2.80.0
8 days13.9±2.86.9±5.00.0
10 days16.70.00.0
  • Changing pattern of 3HTdR LRCs (first column), BrdUrd-labelled cells (second column) and double-labelled LRCs (third column). The data shown here are values for the peak labelling indices taken from cell positional distributions. Data are shown for both the juvenile animal labelling protocol (upper table) and the post-irradiation regeneration labelling protocol (lower table). The number of 3HTdR LRCs remains broadly constant for 8 to 10 days in spite of eight to ten cell divisions. The BrdUrd labelling remains constant for the first 3 days (during which time there would be four to six divisions in the transit cells). Thus BrdUrd labelling can be detected after several rounds of division. In contrast the percentage of double-labelled cells begins at high levels but by the third day falls to zero, that is, all the BrdUrd label is lost from these LRCs (see Fig. 1) after about two cell divisions of the LRCs. This is one representative set of data for each of the two labelling protocols. Less than three mice per group.