Effect of Ga-Al-As laser irradiation on COX-2 and cPLA2-α expression in compressed human periodontal ligament cells
✍ Scribed by Kotoe Mayahara; Akikuni Yamaguchi; Masahito Sakaguchi; Yu Igarashi; Noriyoshi Shimizu
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 116 KB
- Volume
- 42
- Category
- Article
- ISSN
- 0196-8092
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✦ Synopsis
Background and Objective: Prostaglandin E 2 (PGE 2 ), which has bone-resorptive activity, is produced by human periodontal ligament (PDL) cells in response to mechanical stress. We previously reported that low level laser (LLL) irradiation inhibited PGE 2 production in PDL cells in response to mechanical stress; however, the mechanism underlying this inhibitory effect was unclear. Thus, we sought to determine the mechanism underlying the inhibitory effect of LLL on PGE 2 production in compressed PDL cells. Study Design/Materials and Methods: A compressive force of 2.0 g/cm 2 was applied for 24 hours to human PDL cells obtained from premolars extracted for orthodontic treatment. LLL irradiation (Ga-Al-As laser, 830 nm, 3.82 J/ cm 2 ) was applied 6 hours before, 1 hour before, and immediately after the application of compressive force. The mRNA expression of COX-2 and cPLA 2 -a was then examined by real-time PCR. Results: LLL irradiation significantly inhibited COX-2 and cPLA 2 -a mRNA expression, which was increased in response to the application of a compressive force. Moreover, LLL irradiation immediately after compression had the strongest inhibitory effect on the expression of these genes. Conclusions: The inhibition of PGE 2 production by LLL irradiation in compressed PDL cells may be due to the inhibition of COX-2 and cPLA 2 -a expression and is most pronounced immediately after the application of a compressive force.