The purpose of the present study is to investigate the optimal wavelength, frequency and energy density for set up the photobiologic treatment of periodontal disease. To establish the present study, λ scan of 500㎚ to 900㎚ was used to search the optimal wavelength for maximal proliferation of human gingival fibroblasts. Cell proliferation assay was carried out as MTT assay. Light intensity of 0.8 to 3.25mW, frequency of 0 to 584㎐ and 0 to 2hours was applied for investigation of optimal energy density, frequency and applied duration. Finally, 628㎚ with 1mW/cm2 for 1hour of LED irradiation resulted in maximal proliferation of gingival fibroblasts. These results suggest that LED irradiation on gingival fibroblast show different proliferation according to the condition of irradiation, and demonstrate that LED irradiation can control the quantity of cell proliferation.

To investigate the differential expression of genes by 635nm LEDs irradiation in arachidonic acid-treated human gingival fibroblasts, cDNA microarray was carried out. Human gingival fibroblasts were primary cultured and arachidonic acid was treated to induce inflammation. 635nm of wave length was used for LEDs irradiation. The experimental group was categorized into four group ; control, only LEDs irradiation group, only arachidonic acid-treated group and arachidonic acid-treated with LEDs irradiation group. The expression of 8,078 genes were increased and the expression of 7,103 genes were decreased in only LEDs irradiation group. For arachidonic acid-treated with LEDs irradiation group, the expression of 6,815 genes were increased, while the expression of 8,031 genes were decreased comparing with only arachidonic acid-treated group. IL-13alpha2 receptor was the most expressed gene in LEDs irradiation group comparing with control, followed by MMP3. Genes which the most down regulated was BIRC3 in LEDs irradiation group. PLAB genes was the most up-regulated in arachidonic acid treated with LEDs irradation group, followed by ranked RARRES1. Considering the classification by cell function, genes associated with signal transduction were the most affected by LEDs irradiation, followed by the genes associated with nucleoside, nucleotide and nucleic acid metabolism. In arachidonic acid treated with LEDs irradiation, genes associated with signal transduction and protein metabolism were affected. Taken together, LEDs irradiation could affect various biological process and could identify many genes related to LEDs irradiation, which could be used for clinical application.

The process 0 1' wound healing needs the deposition of collagen and non-collagenous compounds, followed by the remodelling of extracellul ar matrix Recently, it has known that LEDs irradiation can help wound healing to accelerate the cell proliferation. But its mec hanism is not elucidated yot. The purpose of the present study is to observe the expression level of extracellular matrix by 635nm LEDs ir radiation. Human gingival fibroblasts were primary cultured, treated arac hidonic acid (때 and followed by LEDs irradiation. To observe the mRNA expression of extracellular matrix, cDNA mlcroarray was ca n‘ ied out 1n present study, 3 experimental groups were categorized into control, AA-treated group, and AA-treated with LEDs irradiation group. The differential expressions of MMP-1, -2, -3, - 10, - 11, -14, -16, - 17, -25 and TIMP-1, -2, -3. -4 were observed. Especially, mRNA expression of T1MP-3 was 10 fold decreased in arach idonic acid -treated with 635nm LEDs irradiation group. Finally, LEDs irradation can affect the expression level of MMPs and TIMPs, which lead to prolifer ation of gingival fibroblasts and result in would healing

It has been reported that light-emitting diodes(LED) can be used in the treatment of oral diseases. Although bio-stimulatory effects of LED irradiation such as promotion of wound healing have been well known, there are few reports about molecular mechanisms associated with wound healing by LED irradiation. The purpose of the present study was to investigate the expression pattern of various extracellular matrix(ECM) molecules in relation to wound healing after LED irradiation on primary human gingival fibroblasts(hGFs) in vitro. The source of light for irradiation was a continuous-wave LED emitting at a wavelength of 635 nm, and manufactured that energy density was 5 mW/cm2 on sample surfaces. The hGFs were irradiated for 1 hour at 37℃ in 5% CO2 humidified chamber. Experimental samples were acquired at 0 (right after irradiation), 24 and 48 hour after irradiation. To investigate the molecular mechanisms associated with wound healing, we examined the mRNA expression of 6 types of collagens, 7 types of matrix metalloproteinases(MMPs) and 4 types of tissue inhibition of metalloproteinases(TIMPs) after LED irradiation by RT-PCR. The mRNA expression of collagen 4, MMP-3, 9, and 16, and TIMP-3 was influenced by LED irradiation. Generally, the collagen expression of the irradiation group was slightly increased, particularly collagen 4 was significantly increased at 0 hour. The expression of MMP-3 was increased at 0 and 24 hours and MMP-16 was increased at 24 hours, respectively. The expression of MMP-9 was decreased at 0 hour and increased at 24 and 48 hours. The mRNA expression of TIMP-3 was significantly decreased at 24 and 48 hours after irradiation. These results suggest that the altered expression of ECM molecules after LED irradiation may contribute to the accelerated wound healing.

It has been reported that light-emitting diodes(LED) can be used in the treatment of oral diseases. Although bio-stimulatory effects of LED irradiation such as promotes stimulation of wound healing have been well known, there are few reports about molecular mechanism associated with cell cycle by LED irradiation. The purpose of present study was to examine the molecular event in cell cycle of LED irradiation on primary human gingival fibroblast(hGF) in vitro. The source of light for irradiation was a continuous-wave LED emitting at a wavelength of 635nm, and manufactured that energy density was 5mW/cm2 on sample surface. The hGF were irradiated for 1 hour at 37℃ in 5% CO2 humidified chamber. Experimental samples were acquired at 0 (right after irradiation), 8 and 24 hour after irradiation. To investigate the molecular mechanisms associated with cell cycle, growth phase was determined by flow cytometry and mRNA expression of cyclin A, cyclin B, cyclin D1, cyclin E, cdc2, PCNA, p18, p27, p21, and p53 were determined by real time RT-PCR. Flow cytometric analysis demonstrated the percentage of cells in the G1 and S phase were decreased, but the G2 phase increased, which showed cells irradiated by LED were transitioned from S to G2 phase. For mRNA expression, cyclin B, cdc2, PCNA and p53 were increased at 0 hour after irradiation, and most of cell cycle molecules were increased at 8 hour after irradiation. At 24 hour after irradiation, cyclin A, cyclin E, PCNA and p18 were increased. Taken together, LED irradiation induced proliferation of hGF cells through transition from S to G2 phase.

LEDs have been shown to be a safe, efficient, light-weight, and less-expensive alternative to heal wound. LED irradiation at the same biostimulatory wavelength of previous laser studies have similar biochemical effects The purpose of present study is to evaluate the effects of wound healing by LED irradiation. Thirty 34-day-old sprague dawley were used for present study. 1.5mm diameter defected holes were formed in both ear lobes of rat by rubber dam punch. 635nm and 890nm irradiation was performed by LED for 2 weeks, followed by histologíc examination staíned with H&E and Masson trichrome. Also, RT-PCR was carried out to find out the mRNA expression level in gingival fjbroblast irradiated by 635nm for 1 hour. In gross exarnination, wound healing was observed in irradiated group comparing to control For microscopic exarnination, repair by connective tissues was filled in defects of irradiated group, while dense cellular bands consisting of fjbroblasts and capi llaries were found at the end of defect in control By staining of masson trichrome, amount of collagens were found in irradiated group. In a result of RT-PCR, mRNA expressions of TGF- ß , MMP-1,3 and Timp-3 were down-regulated in irradiated group comparing with their expression in control group. Taken together, LED irradiation increase the prolifeation and the activity of fibroblasts and down-regualted the TGF-ß , MMP- 1,3 and Timp- 3 mRNA, followed by activation of would healing.