2013 Volume 24 Issue 2 Pages 72-82
This study was performed in order to investigate the effects of Nd:YAG laser irradiation on human gingival fibroblasts (Gin-1), as represented by cell proliferation activity rate and TGF-β1 and Type I collagen production rate, as well as HSP47 expression.
Gin-1 cells were irradiated for 10 seconds at laser outputs of 2W (5pps/400mJ, 100pps/20mJ) and 7.2W (40pps/180mJ, 90pps/80mJ), at irradiation distances of 10mm or 20mm. Culture supernatant was recovered after 3 and 5 days of culture following laser irradiation and investigated for cell proliferation rate (modified MTT), and TGF-β1 and Type I collagen production rate (ELISA method). Gin-1 was also subjected to immunofluorescent staining after 3 hours of culture following laser irradiation, and observed for HSP47 expression by confocal laser scanning microscopy.
On the 5th day of culture, both of the groups irradiated by 2W at 10mm exhibited significantly higher cell proliferation rates than controls, and on the 3rd day of culture the group irradiated by 7.2W (90pps/80mJ) at 10mm exhibited significantly higher TGF-β1 production rates than controls. Among the 10mm irradiation groups on the 3rd day, both of the 7.2W groups exhibited significantly higher Type I collagen production rates than controls. Intracytoplasmic HSP47 expression was found in all groups.
Thus, high-output laser irradiation with an increased irradiation distance exerts a cell activating effect without harmful heating, similar to that of low-output laser irradiation.