REACTIVE CHANGE IN PROLIFERATIVE ACTIVITY OF THE JUNCTIONAL EPITHELIUM AFTER TOPICAL APPLICATION OF LIPOPOLYSACCHARIDE

Citation
T. Takata et al., REACTIVE CHANGE IN PROLIFERATIVE ACTIVITY OF THE JUNCTIONAL EPITHELIUM AFTER TOPICAL APPLICATION OF LIPOPOLYSACCHARIDE, Journal of periodontology, 68(6), 1997, pp. 531-535
Citations number
22
Categorie Soggetti
Dentistry,Oral Surgery & Medicine
Journal title
ISSN journal
00223492
Volume
68
Issue
6
Year of publication
1997
Pages
531 - 535
Database
ISI
SICI code
0022-3492(1997)68:6<531:RCIPAO>2.0.ZU;2-5
Abstract
IT IS WELL ESTABLISHED THAT apical migration of junctional epithelium (JE) along a root surface is an important factor in periodontal pocket formation and deepening. However, the exact mechanism and, more speci fically, the role of inflammatory products in influencing the activity of cells within the JE is not known. To address this issue lipopolysa ccharide (LPS) was applied topically into rat molar gingival sulcus an d then tissues evaluated immunohistochemically for expression of proli ferating cell nuclear antigen (PCNA). Tissues were prepared for histol ogical analysis at designated times. Histologically, infiltration of n eutrophils with associated edema was noted in JE and gingival connecti ve tissues 6 hours after LPS application and was prominent at 12 hours . These inflammatory changes persisted in the 2- and 3-day specimens, and disappeared at 5 days. In normal gingiva, before the LPS applicati on, the JE showed few PCNA positive cells, while almost all cells in t he basal and suprabasal cell layers of the oral gingival epithelium an d the oral sulcular epithelium were PCNA positive. No increase in the number of PCNA positive cells in the JE beyond zero time was observed at 6 and 12 hours after LPS application. One day after LPS application , PCNA positive cells appeared in the basal cell layer of the JE, with a continued increase number of PCNA positive cells in the JE continue d at 2 and 3 days. By day 5 the number of PCNA positive cells were dec reasing with a return to a normal range by 7 days. These results showe d that 1) under normal physiological conditions, cells within the JE h ave minimal mitotic activity and 2) the JE cells can enter the prolife rating cell cycle when exposed to LPS, and suggest that the enhanced p roliferating activity in the JE is an important factor for the deepeni ng of the periodontal pocket, if the connective tissue attachment is b roken down.