Department of Pediatric Dentistry and Othodontic, School of Dentistry of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, SP, Brazil.
Lasers Med Sci. 2012 Jul;27(4):777-83. doi: 10.1007/s10103-011-0968-0. Epub 2011 Aug 13.
The aim of this study was to investigate the osteoblastic activity of cells derived from the midpalatal suture upon treatment with low-level laser therapy (LLLT) after rapid maxillary expansion (RME). A total of 30 rats were divided into two groups: experimental I (15 rats with RME without LLLT) and experimental II (15 rats with RME + LLLT). The rats were euthanized at 24 h, 48 h, and 7 days after RME, when the osteoblastic cells derived from the rats' midpalatal suture were explanted. These cells were cultured for periods up to 17 days, and then in vitro osteogenesis parameters and gene expression markers were evaluated. The cellular doubling time in the proliferative stage (3-7 days) was decreased in cultured cells harvested from the midpalatal suture at 24 and 48 h after RME + LLLT, as indicated by the increased growth of the cells in a culture. Alkaline phosphatase activity at days 7 and 14 of the culture was increased by LLLT in cells explanted from the midpalatal suture at 24 and 48 h and 7 days after RME. The mineralization at day 17 was increased by LLLT after RME in all periods. Results from the real-time PCR demonstrated that cells harvested from the LLLT after RME group showed higher levels of ALP, Runx2, osteocalcin, type I collagen, and bone sialoprotein mRNA than control cells. More pronounced effects on ALP activity, mineralization, and gene expression of bone markers were observed at 48 h after RME and LLLT. These results indicate that the LLLT applied after RME is able to increase the proliferation and the expression of an osteoblastic phenotype in cells derived from the midpalatal suture.
本研究旨在探讨快速扩弓（RME）后低水平激光疗法（LLLT）对颅中缝细胞成骨活性的影响。将 30 只大鼠分为两组：实验组 I（15 只 RME 大鼠无 LLLT）和实验组 II（15 只 RME+LLLT 大鼠）。RME 后 24 h、48 h 和 7 d 处死大鼠，取大鼠颅中缝衍生的成骨细胞进行原代培养。将细胞培养至 17 d，评估体外成骨参数和基因表达标志物。RME+LLLT 后 24 h 和 48 h 培养的细胞在增殖期（3-7 d）的细胞倍增时间缩短，细胞培养中细胞生长增加。碱性磷酸酶活性在 RME 后 24 h、48 h 和 7 d 时，培养的细胞中碱性磷酸酶活性在第 7 天和第 14 天增加。在所有时期，RME 后 LLLT 可增加第 17 天的矿化。实时 PCR 结果表明，RME 后 LLLT 组细胞的碱性磷酸酶、Runx2、骨钙素、I 型胶原和骨涎蛋白 mRNA 水平均高于对照组细胞。RME 和 LLLT 后 48 h 观察到碱性磷酸酶活性、矿化和骨标志物基因表达的作用更明显。这些结果表明，RME 后应用 LLLT 能够增加颅中缝衍生细胞的增殖和骨形成表型的表达。
