Effect of low level laser irradiation on the expression of periostin in human periodontal ligament cells
Date Issued
2014
Date
2014
Author(s)
Chu, Wan-Ni
Abstract
Low level laser irradiation by giving proper dose application contributes to anti-inflammatory, analgesic, wound healing and other therapeutic purposes. In recent years, the clinical efficacy of the low level laser treatment is also applied to the field of dentistry. Periostin is an extracellular matrix protein highly expressed in periodontal ligament and is essential for periodontal tissue integrity. Its function is as follows regulation of cell adhesion, migration, differentiation and so on. Periostin expression is closely related with the ability of periodontal ligaments to withstand the bite force and the stability of PDL structure. PLAP-1/asporin (periodontal ligament- associated protein) plays specific roles in maintaining the homeostasis of the PDL as a negative regulator of cytodifferentiation and mineralization.
This study investigated the effects of low level laser irradiation on the expression of periostin and PLAP-1 in human PDL cells. Experimental PDL cells were collected from human wisdom teeth or premolars extracted for orthodontic reasons. 970nm semiconductor laser models (Al-Ga-As, Arts K-Laser Professional 40E 970 nm) was used in the study , irradiation parameter was set to continuous wave mode, output power was500 mW, irradiation time was 4 seconds (5.20 J/cm2) , 8 seconds (10.40 J/cm2) , the distance between the tip of the laser handpiece and the button of the culture plate was 11mm. Analysis of low level laser irradiation on PDL cells included MTT assay, expression of periostin mRNA , PLAP-1 mRNA , and periostin, Smad2/3 protein.
The results of this study showed that MTT activity of periodontal ligament cells under 970-nm low level laser irradiation increased significantly over time at different energy density. RT-PCR analysis of gene showed that after one-day low level laser irradiation at energy density of 5.20 J/cm2, periostin mRNA and PLAP-1 mRNA expression increased. Western blot analysis showed that periostin expression of periodontal ligament cells was enhanced with the presence of TGF-β. The impact of a single low-level laser irradiation on periostin protein expression in periodontal ligament cells were decreased first and then back to a similar situation compared with the control groups.
The performance of repeated laser irradiation on periostin expression at different energy density and irradiation days were enhanced or weakened, which were different from those of single irradiation application. This study showed that low-level laser irradiation may enhance the expression of periostin and PLAP-1 in the periodontal ligament cells and thus may affect the homeostasis of periodontal tissue. However, whether the low level laser irradiation activate TGF-β signaling pathway and contribute to the phosphorylation of Smad2/3 remains to be further explored.
Key word: low level laser irradiation、human periodontal ligament cell、Periostin、PLAP-1
Subjects
低階能量雷射照射
人類牙周韌帶細胞
Periostin
PLAP-1
Type
thesis
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