Gavish Lilach, Perez Louise, Gertz S David
Department of Anatomy and Cell Biology, The Hebrew University, Hadassah Medical School, Jerusalem 91120, Israel.
Lasers Surg Med. 2006 Sep;38(8):779-86. doi: 10.1002/lsm.20383.
The vascular extracellular matrix is maintained by a dynamic balance between matrix synthesis and degradation. This equilibrium is disrupted in arterial pathologies such as abdominal aortic aneurysm. Low-level laser irradiation (LLLI) promotes wound healing. However, its effect on smooth muscle cells (SMCs), a central player in these responses, has not been established. The current study was designed to determine the effects of LLLI on arterial SMC proliferation, inflammatory markers, and matrix proteins.
STUDY DESIGN/MATERIALS AND METHODS: Porcine primary aortic SMCs were irradiated with a 780 nm laser diode (1 and 2 J/cm(2)). Trypan blue exclusion assay, immunofluorescent staining for collagen I and III, Sircol assay, gelatin zymography, and RT-PCR were used to monitor proliferation; collagen trihelix formation; collagen synthesis; matrix metalloproteinase-2 (MMP-2) activity, and gene expression of MMP-1, MMP-2, tissue inhibitor of MMP-1 (TIMP-1), TIMP-2, and IL-1-beta, respectively.
LLLI-increased SMC proliferation by 16 and 22% (1 and 2 J/cm(2), respectively) compared to non-irradiated cells (P<0.01 and P<0.0005). Immediately after LLLI, trihelices of collagen I and III appeared as perinuclear fluorescent rings. Collagen synthesis was increased twofold (2 days after LLLI: 14.3+/-3.5 microg, non-irradiated control: 6.6+/-0.7 microg, and TGF-beta stimulated control: 7.1+/-1.2 microg, P<0.05), MMP-2 activity after LLLI was augmented (over non-irradiated control) by 66+/-18% (2 J/cm(2); P<0.05), and MMP-1 gene expression upregulated. However, TIMP-2 was upregulated, and MMP-2 gene expression downregulated. IL-1-beta gene expression was reduced.
LLLI stimulates SMC proliferation, stimulates collagen synthesis, modulates the equilibrium between regulatory matrix remodeling enzymes, and inhibits pro-inflammatory IL-1-beta gene expression. These findings may be of therapeutic relevance for arterial diseases such as aneurysm where SMC depletion, weakened extracellular matrix, and an increase in pro-inflammatory markers are major pathologic components.
血管细胞外基质通过基质合成与降解之间的动态平衡得以维持。这种平衡在诸如腹主动脉瘤等动脉病变中会被打破。低强度激光照射（LLLI）可促进伤口愈合。然而，其对平滑肌细胞（SMC）（这些反应中的关键参与者）的影响尚未明确。本研究旨在确定LLLI对动脉SMC增殖、炎症标志物和基质蛋白的影响。
研究设计/材料与方法：用780纳米激光二极管（1和2焦耳/平方厘米）照射猪主动脉原代SMC。采用台盼蓝排斥试验、I型和III型胶原免疫荧光染色、Sircol检测、明胶酶谱分析以及逆转录-聚合酶链反应（RT-PCR）分别监测增殖、胶原三螺旋形成、胶原合成、基质金属蛋白酶-2（MMP-2）活性以及MMP-1、MMP-2、MMP-1组织抑制剂（TIMP-1）、TIMP-2和白细胞介素-1β（IL-1-β）的基因表达。
与未照射细胞相比，LLLI使SMC增殖分别增加了16%和22%（分别为1和2焦耳/平方厘米）（P<0.01和P<0.0005）。LLLI照射后即刻，I型和III型胶原的三螺旋呈现为核周荧光环。胶原合成增加了两倍（LLLI照射后2天：14.3±3.5微克，未照射对照组：6.6±0.7微克，转化生长因子-β（TGF-β）刺激对照组：7.1±1.2微克，P<0.05），LLLI照射后MMP-2活性（相对于未照射对照组）增强了66±18%（2焦耳/平方厘米；P<0.05），且MMP-1基因表达上调。然而，TIMP-2上调，MMP-2基因表达下调。IL-1-β基因表达降低。
LLLI刺激SMC增殖，促进胶原合成，调节调节基质重塑酶之间的平衡，并抑制促炎性IL-1-β基因表达。这些发现可能对诸如动脉瘤等动脉疾病具有治疗意义，在这些疾病中，SMC减少、细胞外基质减弱以及促炎标志物增加是主要的病理成分。
