Progenitor connective tissue cell populations in the gingival papilla of the rat

Abstract

The purpose of this study was to demonstrate the presence and anatomical positions of connective tissue progenitor cell populations in the gingival papilla of the rat. Ten male hooded Lister rats aged 4 wk were killed 1 h after flash labelling with tritiated thymidine. Paraffin sections were cut through the molar regions of 19 mandibles parallel to the occlusal plane. Sections immediately apical to the epithelium of the col and just coronal to the crest of the interdental septum (levels 1 and 5) were chosen for autoradiography, as were a further three sections (levels 2, 3 and 4), spaced equidistantly between levels 1 and 5 in a subsample of 10 of these mandibles. Mean labelling indices (LIs) for all 19 specimens were significantly higher within 5 μm of the teeth at levels 1 and 5, and in a zone 15–25 μm from the teeth in level 5. LIs for the subsample of 10 mandibles were also significantly higher within 5 μm of the teeth in levels 3 and 5, and within 15–20 μm in levels 4 and 5. Nuclear densities were highest at all levels within 10 μm of the teeth and at 20 μm (levels 1–3) or 30 Jan (levels 4 and 5) from the teeth. The data are consistent with the existence of ostensible connective tissue progenitor cell populations, one in contact with cementum and junctional epithelium, the other lying in the body of the papilla at its most apical levels, 15–25 μm from the teeth.

Early Cellular Reactions in Mechanically Stimulated Gingival Connective Tissue

“…The occurrence of conspicuous tissue deformation in the area of interest was verified by measurements of periodontal ligament width changes [15] and was distinctly visible under microscope during data collection (see Figure 1). Assessment of gingival connective tissue cell proliferation which was carried out in areas of gingival connective tissue known to be rich in progenitor cells [9,16], revealed PLC zwischen Rattenmolaren erzeugt Initialkräfte von ca. 0,14 N [4], deren Höhe durch die innerhalb von Minuten eintretende Molarenbewegung und Alveolarknochenverformung schnell abnimmt [7,36].…”

“…Die Evaluierung der GCT-Zellproliferation, die in progenitorzellreichen [9,16] GCT-Arealen durchgeführt wurde, ergab unter Kontrollbedingungen des physiologischen Gleichgewichts PLC-Werte zwischen 0,7 und 4,5% (s. Tabellen 1 und 2). Sie sind mit berichteten [16] Werten vergleichbar und bestätigen -als Manifestation einer beachtlichen homöostatischen Zellteilungsaktivität -die Existenz von Progenitorzellpopulationen unter GCT-Zellen [9,12,16].…”

“…It has been demonstrated that at least three fibroblast progenitor populations are present in distinct tissue locations and with differing steady-state cell kinetic properties within gingival lamina propria [9,12,16]. These cells maintain a substantial level of homeostatic proliferative activity [17,18] and can undergo amplification division in response to induced inflammation [9,12,14] and wounding [19,28].…”

Periodontal ligament cell populations: The central role of fibroblasts in creating a unique tissue

“…Complementary studies of steady-state and wounded responses have provided evidence that fibroblast progenitors have a common paravascular location (Gould et al, 1980;McCulloch, 1985;Pender et al, 1988) and that the cells colonizing periodontal wounds are derived from adjacent, unwounded periodontal ligament (Gould et al, 1980). Experimental approaches that have used cell kinetic and cell culture methods indicate that periodontal ligament fibroblasts in adult rodents are derived from cells of both the periodontal ligament and endosteal spaces (Melcher et al, 1986;McCulloch et al, 1987).…”

Experimental Regeneration of The Periodontium

“…Using 3 H labeling (flash labeling), Pender et al 25 have identified two progenitor cell populations in the lamina propria of gingiva -one in contact with cementum and junctional epithelium and the second lying in the body of the papilla at its most apical level. These two populations appear to extend coronally from the level of the crest of the interdental septum, suggesting that their origin may be from the periodontal ligament and/or alveolar bone.…”