The pattern of wound healing process differs markedly according to the cell types. Gingival wounds heal more rapidly without scar, however dermal wounds show collagen laid down in thick disorganized patterns and keloid formation. This h as b een s uggested t o be d ue t o the presence of d ifferent E C M components a nd c ytokines a s well a s growth factors. The purpose of this study was to examine the differential expression of genes in connection with keloid formation in gingival fibroblasts (hGFs) and dermal fibroblasts (hDFs) in response to inflammation. In this study, we investigated the differences between hGFs and hDFs in the expression and production of cyclooxygenase (COX-2), prostaglandins E2 (PGE2), transforming growth factor (TGF)-β, collagens, matrix metalloproteinases (MMPs), and tissue inhibitors of matrix metalloproteinases (TIMPs) which play important roles in collagen deposition in wound healing. The hGFs and hDFs were primary cultured and allocated to arachidonic acid (AA) treatment group and control group. Protein and mRNA were extracted right after (0 hr) and 24 hr after AA treatment. At a defined concentration of AA in hGFs and hDFs, MTT assay was performed. The mRNA and protein expression levels of COX-2, TGF-β, collagen 1 and 3, MMP 1 and TIMP 1 were examined by Real-time PCR and Western blots. The amounts of PGE2 were measured by enzyme-linked immunosorbent assay (ELISA).The expression of COX-2 and TGF-β exhibited reduced levels in hGFs , but were increased in hDFs at 24 hr after AA treatment. Production of PGE2 was increased in hGFs and hDFs at right after AA treatment but, not changed at 24 hr after AA treatment. The protein and mRNA expression of collagen 1 and 3 were decreased in hGFs , whereas increased in hDFs at 24 hr AA treatment. Expression of MMP-1 protein was increased in hGFs at 24 hr but, was decreased in hDFs at 24 hr compared with that of control. The protein expression of TIMP-1 was decreased in hGFs but, was increased in hDFs at 24 hr compared with that of control. These observations demonstrate differential expression between gingival and dermal fibroblasts in regulation of collagenolytic capacity by extracellular matrix-associated genes in keloid formation associated with wound repair.

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.

The purpose 01' pl'esent study was to examine the molecular events in apoptosis by CoCl2, mimicking hypoxic cond ition and recovering effects by LED ir l'adiation on Human SH-SY5Y neuroblastoma cells The SOUl'ce 0 1' light for ir l'adiation was a continuous-wave LED emitting at a wavelenl양h of 590 nm, and manufactured that ene rgy density was 5 mW!cm2 on sample surface, After ir l'adiation, cell viabi lity was measured with BrdU , cell morphol ogy was examined with Diff- Quik staining, cell signaling was monitored with various apoptosis-related molecules using RNase Pl'otection Assay(RPA) , W11en treated with CoC12, apoptotic induction was found in the SH-SY5Y cells in a concentration-dependent and time-dependent manner , Diff-Quik s taining was revealed that DNA fragmentation re presented apoptosis was examined in CoC12-tl'eated group, Moreover, RPA assay of SH-SY5Y cclls lIs ing val'iolls apoptosis-related molecllles showed that the apoptotic cell population was mcreased J-loweve. there was sorne signifïcant change in LED irradiatied cells aftel' treatement of CoC12 The main mechanism for Lhese a poptosis appearecl to be mito c hondriεt - m ecliated pathway, such as cytochrome- c‘ caspase-9, caspase-3, pro-apototic protein ßax, anti-apototic protein Bcl-2, and death receptor• mediated pathway, such as Fas, cas pase- 8, a ncl TNFRl These results demonstrate that CoCI2 induce apoptosis in SH-SY5Y via different dual apop tosis pathway through death receptor pathway as well as mitochondria- dependent pathway and LED irradiation can recl llces the CoCl2-induced apoptosis by blocking their internal signaling pathway

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.