title: Migration and proliferation of progenitor cells in the connective tissue of rat gingival papilla.
abstract: The aim of this investigation was to determine whether gingival fibroblast progenitor cells undergo division and whether there is evidence of migration of their progeny from the paravascular sites within the interdental gingival septum (IGS). 30 male hooded Lister rats aged 6 weeks, were killed in groups of ten, 3, 75 and 171 h after a single injection of tritiated thymidine. Autoradiographs were examined of transverse Historesin sections of the papilla between second and third mandibular molars in 29 specimens, taken from equidistant intervals between the col and alveolar bone crest. Median grain counts in the whole papilla were greatest within 10 microns of blood vessels at 3 h (p < 0.02) and decreased throughout the papilla with time (p < 0.0001). The median grain counts at level 5, nearest the periodontal ligament, were greatest at all times (p < 0.01). The distance of labelled nuclei from blood vessel walls increased with time, most notably at level 5 (p < 0.001). The mean Clustering Index increased (p < 0.01) from 4.6% at 3 h to 12.3% and 11.6% at 75 h and 171 h respectively. At 75 h, the median grain count of clustered nuclei was smaller (p < 0.01) than that of non-clustered nuclei. These data are consistent with the occurrence of clonal division and migration within the IGS and the presence of a slowly cycling cell population near to the periodontal ligament.
mesh_terms: D000818:Animals; D001345:Autoradiography; D002454:Cell Differentiation; D002455:Cell Division; D002465:Cell Movement; D002467:Cell Nucleus / Q000502:physiology; D016000:Cluster Analysis; D003238:Connective Tissue / Q000098:blood supply; D003239:Connective Tissue Cells; D005347:Fibroblasts / Q000502:physiology; D005881:Gingiva / Q000098:blood supply / Q000166:cytology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D018709:Statistics, Nonparametric; D013234:Stem Cells / Q000502:physiology*