Study of extrinsic apoptotic pathway in oral Lichen Planus using TNFR 1 and FasL immunohistochemical markers and TUNEL technique

Abstract

Objective: The exact pathogenesis of lichen planus (LP) is still unknown and there are some controversies concerning role of apoptosis in its creation. The purpose of the present study is to investigate extrinsic apoptotic pathway in oral lichen planus(OLP). Methods: In the present cross-sectional study, the presence of apoptosis was investigated on 25 specimens of OLP and 6 specimens of normal oral mucosa using TUNEL technique and also pro apoptotic immunohistochemical (IHC) markers of FasL and TNFR1 in 4 areas of degeneration, basal and parabasal layers, and lymphocytic band. Then staining intensity distribution (SID) index was determined and the results were analyzed by Wilcoxon and Mann-Whitney tests (P-value < 0.05). Results: There was no significant difference between SID of TUNEL in the areas of parabasal and lymphocytic band, but the difference was significant among other areas. There was significant difference between SID of TNFR1 in the areas of degeneration and lymphocytic band, basal and lymphocytic band and also parabasal and lymphocytic band, but there was no significant difference between other areas. There was no significant difference between SID of FasL in the areas of degeneration and basal, degeneration and parabasal, and also basal and parabasal, but there was significant difference in other areas. Conclusions: Apoptosis probably doesn't play a major role in destruction of basal cells in OLP. Destruction of basal cells in OLP is probably resulting from necrosis of these cells. Because of low level or lack of apoptosis, there is low probability of carcinomatous changes in OLP.