The biological effect of low level laser therapy: Applications on anti-inflammation and bone regeneration

• Main Authors: Ji-Hua Lee, 李基華
• Other Authors: Yan-­Hsiung Wang
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/w4hn8k

博士 === 高雄醫學大學 === 牙醫學系博士班 === 106 === Chronic periodontitis is a common disease among the general population. The main contributing factor to periodontitis is inadequate oral hygiene. Prolonged inflammation results in tooth mobility, periodontal abscesses, and occlusal dysfunction. Patients of periodontitis with poorly controlled diabetes have more rapid recurrence of deep pockets and less favorable long-term outcome. Management of the chronic inflammation of the periodontium is an important issue. Low level laser therapy (LLLT) or low level laser irradiation (LLLI) has been an accepted clinical application producing a positive photochemical and photobiological effect for more than 30 years as a non-invasive mechanical therapy. LLLT has been used in many fields, such as pain relief, tissue repair and anti-inflammation. Our previous studies found that LLLT suppressed stem cell inflammation induced by lipopolysaccharide (LPS) and diminished gene expressions of pro-inflammatory cytokines like IL-6 and IL-1. We also noted that LLLT promoted the proliferation and osteogenic differentiation of stem cells. However, the anti-inflammatory mechanism of LLLT that inhibits pro-inflammatory cytokines has not been revealed and the effect of LLLT on bone regeneration of diabetes mellitus is also unclear. Therefore the purposes of this study were first to investigate the anti-inflammatory effect of LLLT on human periodontal ligament cells (hPDLCs) and possible mechanism. Second, to study the therapeutic effects of LLLT on bone regeneration under hyperglycemia. In vitro study, LPS was used to establish an inflammatory reaction in hPDLCs and then irradiate with low level laser. We analyzed the mRNA expression of pro-inflammatroy cytokines (IL-1β, IL-6, IL-8, TNF-α) and the expression level of cyclic AMP (cAMP) and NF-κB. In vivo study, diabetic rats with calvarial defect were used to evaluate the effect of LLLT on bone regeneration. We found that LLLT might inhibit LPS-induced inflammation in hPDLCs through cAMP/NF-κB regulation. Moreover, we found that LLLT promoted the bone healing of calvarial defects of diabetic rats. These results indicate that LLLT could become a useful future periodontal clinical application.