AIM: To study the possible role of nitric oxide (NO) in the development of periodontitis and the relationship between the NO concentration and the attachment loss. METHODS: Seventy- two Sprngue- Dawley rats were randomly assigned to two groups, the control group and periodontitis group. Experimental periodontitis in rats was produced by a ligature of braided silk. The nitric oxide concentration was indirectly ascertained by the concentration of nitrite (NO2-) and nitrate (NO3-)in the gingival tissue, which was assayed by spectrophotometry. The attachment loss (AL) was measured by the technology of the cellular graphics engineering research. The histopathologic change in periodontium was observed under a light microscope by using the histotomy. RESULTS: Compared to control group, the NO2-/NO3 - concentration in gingival tissue was significantly higher in periodontitis group at four weeks and eight weeks following ligation (P＜0.01). In periodontitis group, the NO2-/NO3 - concentration in gingival tissue was higher at eight weeks than that at four weeks following ligation (P＜0.01). At four weeks and eight weeks, the AL in experimental periodontitis in rats was significantly increased than that at one week after ligation ( P＜0.01); and the AL was also much higher at eight weeks than that at four weeks (P＜0.01). CONCLUSIONS: The NO2-/NO3- concentration in the gingival tissue in periodontitis group was significantly higher than that in control group. These results demonstrate that the NO2-/NO3- concentration is related to the severity of AL, and NO synthesis is very important to the process of inflammation and lesion in periodontium. Reducing NO production may be of great therapeutic value in the treatment of periodontitis.%目的:通过建立大鼠牙周炎实验模型,测量牙龈组织中亚硝酸盐(NO2-)和硝酸盐(NO3-)的含量,比较一氧化氮(NO)含量与附着丧失(AL)的关系,探讨NO在牙周炎病理进程中的作用.方法:健康Sprague-Dawley大鼠共72只,随机分为两组:正常对照组和牙周炎组,每组36只.参照Di Paola法复制大鼠牙周炎动物模型.分别于术后1、4和8周时处死动物,每个时点每组处死的动物数为12只.采用分光光度仪测量大鼠牙龈组织中亚硝酸盐(NO2-)和硝酸盐(NO3-)的含量,以间接确定NO含量;采用组织切片法观察牙周组织的组织学改变;应用Tiger细胞图像仪测量AL.结果:术后4周和8周时,实验性牙周炎组牙龈组织NO2-/NO3-含量明显高于正常对照组(P＜0.01);在牙周炎组,术后8周牙龈组织NO2-/NO3-含量明显高于术后4周(P＜0.01).在牙周炎组,术后4周和8周与术后1周比较,AL显著增加(P＜0.01);术后8周与4周比较,AL显著增加(P＜0.01).结论:牙周炎组牙龈组织NO2-/NO3-含量明显高于正常对照组;NO2-/NO3-含量与牙周组织的AL直接相关.结果表明NO在牙周组织的炎症和破坏过程中发挥作用,提示在牙周炎的治疗中控制NO具有临床应用价值.
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Laboratory of Malaria and Vector Research,National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 - 0425, USA;
