Inflammatory mediators induced by mechanical stress in gingival epithelial cell

Objective: The purpose of this study is to examine the inflammatory mediators induced by mechanical stress in mouse-gigival epithelial cell line, GE-1.

Methods: GE1 cells are obtained from RIKEN Cell Bank. In order to determine the effect of static compressive force, GE1 cells were embedded and cultured in a three dimensional collagen gel system (3D-gel) to mimic in vivo conditions. 3D-gel was cultured for 24 h with 2 ml of SFM-101 containing 1%FBS prior to force loading. Compressive force was applied using titanium plate placed over the gels, which was adjusted by adding weight to the cylinder. GE1 cells were subjected to 2.5, 5.0, 7.5, 10.0 g / cm2 of compressive force for 3 h, or to a constant compressive force (5.0 g /cm2) for 1, 3, 6, 12, 24 or 48 h. After the application of compressive force, total RNA was extracted and analyzed by RT-PCR. The amount of PGE2 released into culture medium was measured by ELISA.

Results: Under the compressive force, the expression of Cox-2 mRNA in GE1 cells increased in a force dependent manner up to 5.0 g/cm2. The expression of mRNA of IL-1β, IL-6, and TNF-αmRNA increased, compared with the control group. The time-course experiment showed that Cox-2 mRNA increased when the cells were cultured for 6 h, but the expression slightly reduced after 12 h. On the other hand, Cox-1 mRNA expression was not changed under the compressive force. PGE2 in the conditioned medium was increased up to 12 h, compared with the control group.

Conclusion: These results demonstrated that inflammatory mediators, PGE2, IL-1β, IL-6 and TNF-α were induced by mechanical stress in GE1 cells.