Hamajima S, Hiratsuka K, Kiyama-Kishikawa M, Tagawa T, Kawahara M, Ohta M, Sasahara H, Abiko Y
Nihon University School of Dentistry at Matsudo, Chiba, Japan.
Lasers Med Sci. 2003;18(2):78-82. doi: 10.1007/s10103-003-0255-9.
Many studies have attempted to elucidate the mechanism of the biostimulatory effects of low-level laser irradiation (LLLI), but the molecular basis of these effects remains obscure. We investigated the stimulatory effect of LLLI on bone formation during the early proliferation stage of cultured osteoblastic cells. A mouse calvaria-derived osteoblastic cell line, MC3T3-E1, was utilised to perform a cDNA microarray hybridisation to identify genes that induced expression by LLLI at the early stage. Among those genes that showed at least a twofold increased expression, the osteoglycin/mimecan gene was upregulated 2.3-fold at 2 h after LLLI. Osteoglycin is a small leucine-rich proteoglycan (SLRP) of the extracellular matrix which was previously called the osteoinductive factor. SLRP are abundantly contained in the bone matrix, cartilage cells and connective tissues, and are thought to regulate cell proliferation, differentiation and adhesion in close association with collagen and many other growth factors. We investigated the time-related expression of this gene by LLLI using a reverse transcription polymerase chain reaction (RT-PCR) method, and more precisely with a real-time PCR method, and found increases of 1.5-2-fold at 2-4 h after LLLI compared with the non-irradiated controls. These results suggest that the increased expression of the osteoglycin gene by LLLI in the early proliferation stage of cultured osteoblastic cells may play an important role in the stimulation of bone formation in concert with matrix proteins and growth factors.
许多研究试图阐明低强度激光照射（LLLI）的生物刺激作用机制，但这些作用的分子基础仍不清楚。我们研究了LLLI在培养的成骨细胞早期增殖阶段对骨形成的刺激作用。利用从小鼠颅骨分离得到的成骨细胞系MC3T3-E1进行cDNA微阵列杂交，以鉴定在早期被LLLI诱导表达的基因。在那些表达至少增加两倍的基因中，骨形成蛋白/ mimecan基因在LLLI后2小时上调了2.3倍。骨形成蛋白是细胞外基质中的一种富含亮氨酸的小分子蛋白聚糖（SLRP），以前被称为骨诱导因子。SLRP大量存在于骨基质、软骨细胞和结缔组织中，被认为与胶原蛋白和许多其他生长因子密切相关，调节细胞增殖、分化和黏附。我们使用逆转录聚合酶链反应（RT-PCR）方法，更精确地使用实时PCR方法研究了LLLI对该基因的时间相关表达，发现与未照射的对照组相比，LLLI后2-4小时该基因表达增加了1.5-2倍。这些结果表明，在培养的成骨细胞早期增殖阶段，LLLI使骨形成蛋白基因表达增加，这可能与基质蛋白和生长因子协同作用对骨形成刺激发挥重要作用。
