O. Koulouri et al., Cell division, synthetic capacity and apoptosis in periodontal lesions analysed by in situ hybridisation and immunohistochemistry, J CLIN PER, 26(8), 1999, pp. 552-559
In this study, we investigated the synthetic and proliferative activity of
infiltrating mononuclear cells in sections of granulation tissue from perio
dontitis lesions in both adult periodontitis (AP) and early onset periodont
itis (EOP) patients. We also investigated the role of apoptosis in the remo
delling of the inflamed tissue. We utilised a Ki-67 antigen specific antibo
dy and a histone messenger RNA (mRNA) probe to detect cells undergoing cell
division in the sections, Oligonucleotide probes for 28S ribosomal RNA and
for the detection of poly A mRNA were utilised to detect cells with synthe
tic capacity. Apoptosis was determined using terminal transferase labelling
of fragmented DNA with Biotin labelled dUTP. Biopsies of granulation tissu
e were obtained from 9 AP patients, from 10 EOP patients and for comparativ
e purposes, biopsies of gingival tissue from 4 patients with AP. There were
no differences regarding the relative proportions of cells with synthetic
capacity or in the numbers of dividing cells in the periodontitis tissue se
ctions. However, we observed an increase in the number of dividing cells in
the AP granulation tissues compared to the AP gingival sections and that t
hese cells were predominantly fibroblast like in appearance. Apoptotic cell
s consisted mainly of connective tissue cells; mainly fibroblasts with few
if any leukocytes being apoptotic other than polymorphonuclear leukocytes.
Only a few cyto-phagocytic macrophages were ever observed in the gingival a
nd granulation tissues. We conclude that the turnover of infiltrating leuko
cytes in inflamed periodontal tissue is low, that they probably arrive at t
his site by recruitment from distant lymph nodes, and that neither cell div
ision nor programmed cell death significantly alter the numbers of inflamma
tory cells. On the other hand, fibroblast apoptosis and cell division occur
within the periodontium as these are typical processes in the normal turno
ver and remodelling of these tissues.