Effect Of Low-level 658nm Laser Irradiation On The Biological Activity Of Human Periodontal Ligament Cells

Objective:To investigate the effect of low-level 658nm laser irradiation on the biological activity of human periodontal ligament cells(hPDLCs).Methods:1.hPDLCs obtained from premolar periodontal ligaments were cultured according to the method of modified tissue culture.Morphological observation was determined by hematoxylin and eosin stain, the expression of vimentin and cytokeratin and mineralinzation were used to characterize the cell lineage.2.hPDLCs were subcultured on 96-well tissue culture plates and cultured for 24h, monnolayers were irradiated with an 658nm laser operated at a power output of 11mw in the continuos wave mode at different energy fluences of 1.86J/cm~2,3.72J/cm~2. Untreated cells were used as controls.The proliferation and ALP activity of the laser and control groups were determined different hours after irradiation.3.After laser irradiation, the secretion of fibronectin was measured by enzyme-linked immunosorbent assay(ELISA).Results:1.The hPDLCs were clutured successfully.By immunocytochemical analysis, hPDLCs were positive to antibodies against vimentin,and negative to cytokeratin. After induced by minerlization induce medium for five weeks, hPDLCs were able to form mineralized nodules.2.The MTT tests showed that laser irradiation for 1.86J/cm~2 and 3.72J/cm~2 significantly stimulated proliferation activity than the controls.hPDLCs exposed to 3.72J/cm~2 showed an significant increase in ALP activity.3.After 72h of laser irridiation, energy density for 1.86J/cm~2 accelerated the secretion of fibronectin. Conclusion:1.Modified tissue culture techniques is an effctive method for culture of hPDLCs.2.Low-level 658nm laser irridiation can promote the proliferation and ALP activity of hPDLCs.3.Suitable low-level laser irridiation is able to facilitate hPDLCs to secrete fibronectin.