Meeting Abstract
P3.108 Jan. 6 Cell Proliferation and Migration in Regeneration in Lumbriculus variegatus TWEETEN, Kay A.*; ANDERSON, Amy; College of St. Catherine; College of St. Catherine katweeten@stkate.edu
Following fragmentation, Lumbriculus variegatus, a freshwater oligochaete, exhibits regeneration. Fragments regenerate complete worms with anterior fragments forming segments that differentiate into posterior structures (and vice versa) and middle segments forming both anterior and posterior structures. Since there are conflicting reports in the scientific literature regarding cell proliferation during regeneration in annelids, this activity in regenerating L. variegatus was studied. Mitosis was blocked through incubation of cut worms in 2.5 mM colchicine or 25 &mug/ml vinblastine sulfate. Worms incubated in these drugs exhibited a loss of regeneration in both heads and tails. Because colchicine and vinblastine may affect cellular processes other than mitosis, more direct evidence of cell proliferation was obtained by soaking regenerating worms in 5 mM bromodeoxyuridine (BrdU). At various times following the BrdU treatment, worms were fixed and macerates of regenerating tissue were prepared. The dispersed cells were stained with antibodies against BrdU followed by incubation with FITC-conjugated secondary antibodies. Incorporation of BrdU into cell nuclei was observed with extensive labeling detected in cells harvested at 120 hours into regeneration compared to tissues harvested at 24 or 48 hours. Proliferation of cells, based on BrdU labeling, was observed in both regenerating heads and tails. The results also suggested that the first several days of regeneration consisted of cellular processes other than cell proliferation. To investigate the potential role of cell migration in the regenerative process, worm fragments were incubated in 7.5 &muM locostatin or 0.15 &muM latrunculin B. Both drugs inhibited regeneration of heads and tails. The studies suggested that regeneration in L. variegatus involves cell migration followed by cell proliferation.
