中文摘要：

目的探讨雌激素水平降低与牙周炎之间的关系。方法 30只雌性Wister大鼠随机分为对照组、假手术组和去势组。利用丝线结扎牙齿的方法对去势组和假手术组大鼠构建牙周炎动物模型,免疫组化方法观察MMP-2在各组大鼠牙周组织中的不同表达。结果去势组MMP-2呈强阳性表达,假手术组MMP-2的表达弱于去势组,对照组几乎不表达。同对照组比较,假手术组和去势组的平均光密度值均有统计学意义（P〈0.05）。去势组和假手术组平均光密度值的差异也有统计学意义（P〈0.05）。结论 MMP-2在雌激素低的大鼠牙周组织中的表达比雌激素正常的大鼠高,说明雌激素水平降低加重牙周组织的破坏。

英文摘要：

Objective To study the correlation between estrogen level and periodontitis.Methods Thirty female Wister rats were randomly divided into control group,sham operation group and ovariectomized group.A model of rat periodontitis was established by ligating the second molar of rats in sham and ovariectomized groups with a silk thread.Expression of MMP-2 in periodontal tissue of rats in 3 groups was detected with immunohistochemistry.Results The MMP-2 was strongly and weakly expressed in ovariectomized group and sham operation group,respectively,but nearly not expressed in control group.The mean optical density was significantly higher in sham operation group and ovariectomized group than in control group（P0.05）,and in ovariectomized group than in sham operation group（P0.05）.Conclusion The expression level of MMP-2 is higher in periodontal tissue of rats with a lower estrogen level than in periodontal tissue of rats with a normal estrogen level,indicating that a lower estrogen level can exacerbate the disruption of periodontal tissue.