Immunohistochemical expression of apoptotic factors, cytokeratins, and metalloproteinase-9 in periapical and epithelialized gingival lesions

Abstract

Abstract:The aim of the study was to assess the involvement of apoptotic factors, cytokeratins and metalloproteinase-9 in the histogenesis of both Epithelialized Gingival Lesions (EGL) and Periapical Lesions (PAL). 55 consecutive patients, 30 with PAL and 25 with EGL, were selected for the study after clinical and radiological examinations. The PAL patients had severe periapical lesions and tooth decay with exposure of the pulp chamber. All PAL and EGL biopsies were surgically extracted, fixed in 10% buffered formalin, and processed for routine light microscopy. Ten biopsies of each category were processed for immunohistochemistry (IHC). Serial paraffin sections were stained by IHC with appropriate antibodies to detect cytokeratins (CKs) 1, 5, 8, 10 and 14, caspase-3 and -9, metalloproteinase-9, and for PCNA and TUNEL assays. Both PAL and EGL showed a high expression of the cytokeratin 1, 5 and 8 with higher expression in EGL. Moreover, CK10 was markedly less intense expressed in EGL compared to PAL, while CK14 was almost three times stronger expressed in EGL. The expression of caspase-3 and -9 was stronger in PAL compared to EGL, however, the difference was only significant for caspase-9. In PAL apoptosis detected by TUNNEL method and the expression of MMP-9 were higher than in EGL, whereas PCNA was significantly more expressed in EGL. The results clearly suggest that both lesions have exclusively an epithelial origin and that epithelial proliferation was correlated with the degree of apoptosis in both entities. PAL and EGL presented mostly similar cytokeratin expression except for CK10 and CK14, though with marked differences in the distribution and intensity of IHC reactions. Finally, the degradation of extracellular matrix in both lesions could be partially attributed to the strong presence of MMP-9.

Caspase-8 and Caspase-9 Functioned Differently at Different Stages of the Cyclic Stretch-Induced Apoptosis in Human Periodontal Ligament Cells

“…Taking together these previous and present results, it is reasonable to suggest that both the extrinsic and intrinsic pathways might have been involved in the cyclic stretch-induced apoptosis in PDL cells, but functioned differently in the apoptosis induced by 6 and 24 h stretches respectively. As to in vivo situation, Tu et al and Leone et al reported the results of immunohistochemistry analysis suggesting the presence of caspase-9 in gingivae from SD rats and from human tissue, respectively [27, 28]. With respect to caspase-8, though there were no published studies showing in situ labelling for caspase-8 in periodontal tissue, the caspase-8 immunohistochemically positive fibroblast-like cells have been observed in human implant interface membrane [29].…”

Effect of calcium hydroxide as intracanal medicament on the expression of caspase‐9 located within the radicular cyst epithelium

“…Apoptosis in the epithelium of periapical lesions has been confirmed by the expression of Bcl‐2 or caspase‐3 . The expression of caspase‐9 has been studied only once, in 20 epithelialised lesions of periapical and gingival origin, showing strong immunoreactivity in high levels in both lesion types . This study did not clarify whether the ‘periapical lesions’ included true radicular cysts or periapical granulomas with epithelial cells.…”

“…When the cell has run out of ATP, the ATPase cannot function properly; this leads to an uncontrolled influx of calcium ions from the intercellular space into the cell. The expression of caspase-9 has been studied only once, in 20 epithelialised lesions of periapical and gingival origin, showing strong immunoreactivity in high levels in both lesion types (18). The up-regulation of calcium into the mitochondrion results in the release of cytochrome c, which is also transferred into the cytoplasm via the VDAC channel.…”