Wara-aswapati Nawarat, Surarit Rudee, Chayasadom Anek, Boch Jason A, Pitiphat Waranuch
Department of Periodontology, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand.
J Periodontol. 2007 Jun;78(6):1062-9. doi: 10.1902/jop.2007.060398.
Receptor activator of nuclear factor-kappa B (NF-kappaB) ligand (RANKL) and osteoprotegerin (OPG) are critical for homeostatic control of osteoclast activity, suggesting their vital roles in the progression of bone loss in periodontitis. In this study, the expression of RANKL and OPG mRNA and the relationship between these factors and periodontopathic bacteria in periodontal tissue were studied.
Gingival tissue and subgingival plaque samples were collected from 15 patients with chronic periodontitis and 15 periodontally healthy subjects. RNA was extracted from the tissue and subjected to reverse transcription-polymerase chain reaction (RT-PCR) using primers specific for RANKL or OPG. Beta-actin was amplified as a control to ensure equal loading. The intensity of RT-PCR products was analyzed by a densitometer in proportion to the intensity of beta-actin. The numbers of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans were determined by quantitative real-time PCR.
Our results showed increased levels of RANKL mRNA in chronic periodontitis tissues. The RANKL/OPG expression ratio was significantly higher in the periodontitis group compared to the healthy control group (P = 0.001). Interestingly, the expression of RANKL (r = 0.64; P <0.001), but not OPG (r = -0.24; P = 0.20), was significantly correlated with increased numbers of P. gingivalis. A. actinomycetemcomitans was detected in only 6.7% of all sites.
Chronic periodontitis was associated with RANKL mRNA upregulation and increased RANKL/OPG mRNA expression ratio. In addition, our data showed for the first time to our knowledge an association between upregulated RANKL levels and the number of P. gingivalis in clinically obtained periodontal tissues.
核因子-κB受体激活剂配体（RANKL）和骨保护素（OPG）对破骨细胞活性的稳态控制至关重要，提示它们在牙周炎骨质流失进展中发挥重要作用。本研究旨在探讨牙周组织中RANKL和OPG mRNA的表达情况以及这些因子与牙周病原菌之间的关系。
收集15例慢性牙周炎患者和15例牙周健康受试者的牙龈组织及龈下菌斑样本。从组织中提取RNA，使用针对RANKL或OPG的特异性引物进行逆转录-聚合酶链反应（RT-PCR）。扩增β-肌动蛋白作为对照以确保上样量相等。用密度计分析RT-PCR产物的强度，并与β-肌动蛋白的强度成比例。通过定量实时PCR测定牙龈卟啉单胞菌和伴放线放线杆菌的数量。
我们的结果显示慢性牙周炎组织中RANKL mRNA水平升高。牙周炎组的RANKL/OPG表达比值显著高于健康对照组（P = 0.001）。有趣的是，RANKL的表达（r = 0.64；P <0.001）与牙龈卟啉单胞菌数量增加显著相关，而OPG的表达（r = -0.24；P = 0.20）则无此相关性。在所有位点中仅6.7%检测到伴放线放线杆菌。
慢性牙周炎与RANKL mRNA上调及RANKL/OPG mRNA表达比值增加有关。此外，据我们所知，我们的数据首次表明临床获取的牙周组织中RANKL水平上调与牙龈卟啉单胞菌数量之间存在关联。
