Low-level laser therapy (LLLT) is currently being applied to regenerative medicine and dentistry. The purpose of present study was to evaluate the osteoblastic cell reaction after different dose of LLLT in vitro.
Method:
A diode laser (Ga-Al-As, Arts-Laser Model 970, Arts International Biotechnology, Inc., Germany), 920 nm, was used in this study. A 500 mW laser with a beam area of 0.25 cm2 used for 2.5 and 5 seconds delivered 5 J/cm2 or 10 J/cm2. The osteoblastic cell line (MC-3T3-E1) with LLLT (5 J/cm2or 10 J/cm2) was as experimental groups. The mineral trioxide aggregate (MTA) cement extracted in medium was as positive control group. Cell cultured without adding LLLT or MTA extracts were as blank group. The alamar blue stain assay was to detect the cell proliferation. The reverse transcriptase polymerization chain reaction assay was to detect the bone markers [alkalaine phosphatase (ALP), osteopontin (OPN), bone sialoprotein (BSP), osteocalcin (OC), collagen I (Col I) and RANKL ] expression. Data were collected at day 1, 5 and 7 after cell were treated. Results were compared using analysis of variance (ANOVA). Differences in treatment means were analyzed using the Student-Newman-Keul test and were considered to be significant at p<0.05.
Result:
The MC-3T3-E1 absorbance of the experimental and positive control groups were higher than that of blank group at day 7 (p<0.05). The expression of bone markers showed no statistical difference within experimental, positive control and blank groups (p>0.05).
Conclusion:
The LLLT on MC-3T3-E1 can increase the cell growth. The LLLT does not affect the bone markers expression in the present study.