The Role of Myofibroblasts and Mast Cells in Oral Mucosa Repair After Fractional Laser Treatment

The aim of this study was to clarify the features of the reparative process of the rat's oral mucosa in the later periods after fractional laser treatment with an analysis of the possible involvement of mast cells and myofibroblasts in this process. Material and methods. The samples of the oral mucosa of male Wistar rats (n=9) were used as a material for this study. Fractional laser treatment was carried out using stLase (DentalPhotonics, USA) with power P=7–10 W and pulse duration tp=100–200 ms (wavelength 980 nm). Histological sections of the oral mucosa from the control zones (unaffected) and zones treated with laser radiation were stained with hematoxylin and eosin and with Masson’s aniline blue. To identify mast cells, toluidine blue was used. For the detection of blood vessels and myofibroblasts, immunohistochemical reaction to smooth-muscle α-actin was performed. Results. On the 28th day after fractional laser treatment in rat oral mucosa the signs of incomplete repair were present. At this period in laser treated areas within the lamina propria rows of densely adjacent myofibroblasts were found. In the rows of myofibroblasts the mast cells are not visualized, while in the similar areas of the intact mucosa mast cells are present in large numbers. Conclusion. Fractional laser treatment stimulates the prolongation of regeneration process of rat oral mucosa while formation of myofibroblasts occurs in the laser treated zone. During this process mast cells may be involved. The ability to degranulate under laser radiation was shown.