Ionescu Andrei C, Vezzoli Elena, Conte Vicenzo, Procacci Patrizia, Garcia-Godoy Franklin, Brambilla Eugenio
Oral Microbiological and Biomaterials Laboratory, Department of Biomedical Sciences for Health, University of Milan, Italy.
Department of Biomedical Sciences for Health, University of Milan, Italy.
Am J Dent. 2020 Oct;33(5):277-284.
To investigate whether the addition of sodium-DNA (Na-DNA) to chlorhexidine (CHX)-containing mouthwash influenced morphology and viability of a reconstituted human oral epithelium (ROE), and protects ROE against oxidative stress.
Multi-layered 0.5 cm² ROE specimens were positioned inside a continuous flow bioreactor and grown air-lifted for 24 hours. They were treated with phosphate-buffered saline (PBS) (n= 16) or 1 vol% H₂O₂ for 1 minute (n= 16). Then, they were treated for 5 (n= 8) or 30 minutes (n= 8) with the experimental mouthwash solutions containing: 0.2 wt% CHX, 0.2 wt% CHX + 0.2 wt% Na-DNA, 0.2 wt% Na-DNA, PBS. After 60 minutes washout specimens were subjected to tetrazolium-based viability assay (MTT) confocal laser-scanning microscopy (CLSM), and histological evaluation using optical microscopy and transmission electron microscopy (TEM).
ROE treated with Na-DNA for 30 minutes revealed significantly higher viability than PBS, and CHX + Na-DNA showed higher viability after 30-minute treatment than after 5 minutes, suggesting a significant protective activity of Na-DNA. Moreover, the protective effect of Na-DNA on cell viability was higher after the induction of oxidative stress. After treatment with CHX, CLSM revealed cell stress, leading to cell death in the outer layer. On the contrary, specimens treated with Na-DNA showed a much lower number of dead cells compared to PBS, both in the absence or presence of oxidative stress. Histological examination showed that the protective action of Na-DNA formulations reached more in-depth into the epithelium exposed to oxidative stress, due to intercellular spaces opening in the outer epithelium layers, giving way to Na-DNA to the inner parts of the epithelium. It can be concluded that Na-DNA had a topical protective activity when applied for 30 minutes unless the epithelium barrier is damaged, allowing it to act more in-depth.
Na-DNA showed a clear and protective action against cellular degeneration due to oxidative stress and, partly, to the exposure to CHX. Its addition to chlorhexidine mouthwash or gels could be clinically helpful in contrasting the detrimental activity of CHX on oral tissues, and in the preservation of cell viability, control of inflammation and wound healing.
研究在含氯己定（CHX）的漱口液中添加脱氧核糖核酸钠（Na-DNA）是否会影响重组人口腔上皮（ROE）的形态和活力，并保护ROE免受氧化应激。
将多层0.5平方厘米的ROE标本置于连续流动生物反应器内，气升培养24小时。分别用磷酸盐缓冲盐水（PBS）（n = 16）或1体积%的过氧化氢（H₂O₂）处理1分钟（n = 16）。然后，用含以下成分的实验漱口液处理5分钟（n = 8）或30分钟（n = 8）：0.2重量%的CHX、0.2重量%的CHX + 0.2重量%的Na-DNA、0.2重量%的Na-DNA、PBS。冲洗60分钟后，对标本进行基于四氮唑的活力测定（MTT）、共聚焦激光扫描显微镜检查（CLSM），并使用光学显微镜和透射电子显微镜（TEM）进行组织学评估。
用Na-DNA处理30分钟的ROE显示出比PBS显著更高的活力，并且CHX + Na-DNA在处理30分钟后的活力高于处理5分钟后的活力，表明Na-DNA具有显著的保护活性。此外，在诱导氧化应激后，Na-DNA对细胞活力的保护作用更高。用CHX处理后，CLSM显示细胞应激，导致外层细胞死亡。相反，无论是否存在氧化应激，用Na-DNA处理的标本与PBS相比，死细胞数量都要少得多。组织学检查表明，由于外层上皮细胞间隙开放，使Na-DNA能够进入上皮内部，Na-DNA制剂对暴露于氧化应激的上皮的保护作用更深入。可以得出结论，除非上皮屏障受损，否则Na-DNA在应用30分钟时具有局部保护活性，使其能够更深入地发挥作用。
Na-DNA对氧化应激以及部分由接触CHX引起的细胞变性表现出明显的保护作用。将其添加到氯己定漱口液或凝胶中在临床上可能有助于对抗CHX对口腔组织的有害作用，并有助于维持细胞活力、控制炎症和促进伤口愈合。
