中文摘要：

目的了解血浆纤维蛋白原（fibfinogen，Fg）水平及Fg-β455G／A基因多态性与牙周炎程度的关系，探讨Fg在牙周炎与冠心病相关性中的作用。方法选取中、重度慢性牙周炎和牙周健康、龈炎受试对象共121人，采集外周血以Clauss法检测血浆Fg水平，并提取基因组DNA以聚合酶链反应-限制性片段长度多态性法分析各样本Fg-β455G／A基因型。结果中、重度慢性牙周炎患者血浆中Fg水平[（3．45±0．68）g／L]显著高于牙周健康及龈炎者[（2．47±0．42）g／L，P〈0．001]，且Fg—p455A等位基因的存在与Fg水平升高相关；中、重度牙周炎患者Fg—p455A等位基因频率显著高于牙周健康者（P=0．032），A等位基因携带者发生中、重度牙周炎的危险性是不具有A等位基因者的3．135倍（OR=3．135，P=0．008）。结论Fg-13455G／A基因多态性可能决定血浆Fg水平的升高，并使个体对牙周炎的易感性增加、牙周炎程度加重；血浆Fg水平及Fg-β455G／A多态性在牙周炎发生、发展中可能具有重要作用。

英文摘要：

Objective To investigate the relationship between plasma levels of fibrinogen, the-β55 G/A fibrinogen gene polymorphism and the severity of periodontal inflammation and to explore the possible role of fibrinogen in the association of periodontitis with coronary heart disease （CHD）. Methods A total of 121 patients with moderate to severe periodontitis and periodontally healthy and gingivitis controls were enrolled in the study. Peripheral blood samples were collected and the plasma fibrinogen levels were determined by the clotting method of Clauss. Polymerase chain reaction and restriction fragment length polymorphism analysis with Hae m were used to examine the -β455 G/A fibrinogen gene polymorphism. Results Fibrinogen levels were significantly higher in moderately or severely chronic periodontitis patients [ （3.45 ±0. 68） g/L] than periodontally healthy and gingivitis controls[ （2. 47 ± 0. 42） g/L,P 〈 0. 001 ]. The cartier status of the A allele at position -455 in the beta fibrinogen gene was associated with elevated fibrinogen levels and the frequency of the-A455 allele in the beta fibrinogen gene in the patient group was significantly higher than in the control group （ P = 0. 032 ）. Carriers of the -A455 allele were about 3-fold more likely to have moderate or severe periodontitis as compare to individuals without the -A455 allele（ OR = 3. 135 ,P = 0. 008 ）. Conclusions Fg-β455 G/A polymorphism may contribute to the elevated plasma fibrinogen levels and put individuals at higher risk of having severe periodontitis. As the independent risk factor of CHD, fibrinogen levels and Fg-β455 G/A polymorphism may play a role in the pathogenesis of periodontitis.