【作者】 夏登胜； 刘颖； 张春梅； 杨圣辉； 王松灵；

【Author】 XIA Deng-sheng, LIU Yin, ZHANG Chun-mei, YANG Sheng-hui, and WANG Song-lin Salivary Gland Disease Center and the Molecular Laboratory for Gene Therapy, Capital Medical University School of Stomatology, Beijing 100050, China Beijing Institute of Dental Research, Beijing 100050, China

【机构】 首都医科大学口腔医学院涎腺疾病中心及基因治疗分子生物学实验室； 北京口腔医学研究所；

【摘要】 <正>背景及目的:已有研究表明当机体给予硝酸盐负荷后唾液中硝酸盐显示为一个主动摄取的过程,其上升幅度明显高于血浆上升的幅度,是血浆浓度的9倍。硝酸盐在口腔中被某些细菌继续还原为亚硝酸盐。我们以前的研究发现即使在生理状态下,唾液硝酸盐、亚硝酸盐含量相对于血清也是保持较高的浓度,分别是血清的3和5倍。唾液中保持较高的硝酸盐、亚硝酸盐浓度的生理功能目前还未明确。本研究的目的是观察硝酸盐、亚硝酸盐在不同的pH值下对口腔主要致病菌在体外生长的影响。方法:6种口腔常见致病菌包括:变形链球菌NCTC 104449,乳酸杆菌ATCC 4646,牙龈卟啉单胞菌ATCC33277,牙龈二氧化碳噬纤维菌ATCC 33624,核梭杆菌ATCC 10953,白色念珠菌 ATCC 10231。将上述标准菌激活并在液体培养基中增殖培养得到对数期细菌(OD约为1),然后观更多还原

【Abstract】 Background Salivary nitrate showed a positive correlation with plasma nitrate and averaged 9 times the plasma level after nitrate loading. Nitrate in saliva is known to be reduced to nitrite by oral bacteria. Nitrate and nitrite levels in saliva are 3-5 times that of the serum level in physiological condition respectively in our previous study. The biological functions of high saliva nitrate and nitrite are still not well understood. The aim of this in vitro study was to investigate the antimicrobial effects of nitrate and nitrite on main oral pathogens under acidic conditions. Methods Six common oral pathogens including Streptococcus mutans NCTC 10449, Lactobacillus acidophilus ATCC 4646, Porphyromonas gingivalis ATCC 33277, Capnocytophaga gingivalis ATCC 33624, Fusobacterium nucleatum ATCC 10953, and Candida albicans ATCC 10231 were cultured in liquid media. Sodium nitrate or sodium nitrite was added to the media to final concentrations of 0, 0.5, 1, 2, or 10 mmol/L. All microorganism were incubated for 24 to 48 hours, the optical densities (OD) of the cell suspensions were determined and the cultures were transferred to solid nutrient broth media to observe the minimum inhibitory concentration and minimum bactericidal/fungicidal concentration for the six tested pathogens. Results Nitrite at concentrations of 0.5 to 10 mmol/L had an inhibitory effect on all tested organisms at low pH values. The antimicrobial effect of nitrite increased with the acidity of the medium. Streptococcus mutans NCTC 10449 was highly sensitive to nitrite at low pH values. Lactobacillus acidophilus ATCC 4646 and Candida albicans ATCC 10231 were relatively resistant to acidified nitrite. Nitrate at the given concentrations and under acidic conditions had no inhibitory effect on the growth of any of the tested pathogens. Conclusion Nitrite, at a concentration equal to that present in human saliva, is both cytocidal and cytostatic with respect to six principal oral pathogens in vitro, while nitrate at a similar concentration has no antimicrobial effects on these organisms.更多还原