Hidalgo E, Bartolomé R, Barroso C, Moreno A, Domínguez C
Centre d'Investigacions en Bioquímica i Biologia Molecular, Universitat Autonoma de Barcelona, España.
Skin Pharmacol Appl Skin Physiol. 1998 May-Jun;11(3):140-51. doi: 10.1159/000029820.
The aims of this study were to ascertain whether silver nitrate (AgNO3) concentrations below those used in clinical practice inhibit bacterial growth, and in parallel study the cytotoxic effects on human fibroblasts. The cytoprotective effects of fetal calf serum (FCS) were also evaluated. The cytotoxic effects of eight different silver nitrate concentrations were determined by assessing mitochondrial activity of viable cells capable of cleaving tetrazolium salts. Antimicrobial activity of AgNO3, range: 7-550 x 10(-5)%, was tested against Staphylococcus aureus, Citrobacter freundii, and Pseudomonas aeruginosa. Silver nitrate concentrations exerting antimicrobial effects were: S. aureus, >70 x 10(-5)%; P. aeruginosa, >/=270 x 10(-5)%, and C. freundii, >/=550 x 10(-5)%. With 2% FCS, the lowest AgNO3 concentration studied (7 x 10(-5)%) showed cytotoxic effects (cell survival 71 +/- 19%) at only 2 h of incubation. Under these conditions AgNO3 cytotoxicity was time- and concentration-dependent in all exposure periods. Cytotoxicity was greatly enhanced causing 76% fibroblast growth inhibition at concentrations of 14 x 10(-5)% and contact time of 2 h. The AgNO3 concentration of 7 x 10(-5)% was also cytotoxic with 5% FCS in the media compared with controls, although cell survival was higher than with 2% FCS. The cytoprotective action of FCS was clearly shown at the concentration of 10% at which AgNO3 cytotoxicity of 7 x 10(-5)% to 28 x 10(-5)% was partially or completely inhibited. Our results show that AgNO3 at concentrations 100-700 times more diluted than that normally used in clinical practice retained effective inhibitory activity against some of the above-mentioned microorganisms. However, even these concentrations are cytotoxic for cultured fibroblasts. Thus, silver nitrate concentrations up to 100 times more diluted can be used, since they possess bacterial growth-inhibiting power, are less cytotoxic and therefore favour wound healing.
本研究的目的是确定低于临床实践中使用浓度的硝酸银（AgNO₃）是否能抑制细菌生长，并同时研究其对人成纤维细胞的细胞毒性作用。还评估了胎牛血清（FCS）的细胞保护作用。通过评估能够裂解四氮唑盐的活细胞的线粒体活性，确定了八种不同硝酸银浓度的细胞毒性作用。测试了浓度范围为7 - 550×10⁻⁵%的AgNO₃对金黄色葡萄球菌、弗氏柠檬酸杆菌和铜绿假单胞菌的抗菌活性。发挥抗菌作用的硝酸银浓度分别为：金黄色葡萄球菌，>70×10⁻⁵%；铜绿假单胞菌，≥270×10⁻⁵%；弗氏柠檬酸杆菌，≥550×10⁻⁵%。在含有2% FCS的情况下，所研究的最低AgNO₃浓度（7×10⁻⁵%）在孵育仅2小时时就显示出细胞毒性作用（细胞存活率为71±19%）。在这些条件下，AgNO₃的细胞毒性在所有暴露时间段内均呈时间和浓度依赖性。当浓度为14×10⁻⁵%且接触时间为2小时时，细胞毒性大大增强，导致成纤维细胞生长抑制76%。与对照相比，培养基中含有5% FCS时，7×10⁻⁵%的AgNO₃浓度也具有细胞毒性，尽管细胞存活率高于含有2% FCS时。在10%的浓度下，FCS的细胞保护作用明显显现，此时7×10⁻⁵%至28×10⁻⁵%的AgNO₃细胞毒性被部分或完全抑制。我们的结果表明，浓度比临床实践中通常使用的浓度稀释100 - 700倍的AgNO₃对上述某些微生物仍保留有效的抑制活性。然而，即使是这些浓度对培养的成纤维细胞也具有细胞毒性。因此，可以使用稀释倍数高达100倍的硝酸银浓度，因为它们具有抑制细菌生长的能力，细胞毒性较小，因此有利于伤口愈合。
