细菌外排泵抑制剂对光动力疗法抑制牙菌斑生物膜内主要致龋菌作用的影响

Impact of Efflux Pump-Inhibitors on Inhibition of Cariogenic Bacteria in Dental Plaque Biofilms with Photodynamic Therapy

目的探讨细菌外排泵抑制剂(microbial efflux pump Inhibitor,EPI)——维拉帕米对以血卟啉单甲醚(hematoporphyrin monom-ethylether,HMME)为光敏剂的光动力疗法(photodynamic therapy,PDT)抵抗牙菌斑生物膜内主要致龋菌作用的影响。方法以变形链球菌、血链球菌、嗜酸性乳杆菌和粘性放线菌为实验菌株,建立牙菌斑生物膜模型。以维拉帕米作为细菌外排泵抑制剂,根据在PDT过程中加入维拉帕米和光敏剂的先后顺序,实验分为5组:A组:同时加入光敏剂和维拉帕米PDT处理组,B组:先加入维拉帕米后加入光敏剂PDT处理组,C组:先加入光敏剂后加入维拉帕米PDT处理组,D组:单纯PDT处理组,E组:生理盐水处理组。激光照射后平板菌落计数观察PDT作用后牙菌斑内致龋菌的活力。结果与生理盐水处理组相比,单纯PDT处理组牙菌斑内致龋菌存活的数量(CFU/mL)明显减少(P<0.05),其抑菌率高达95.26%,与单纯PDT处理组相比,加入维拉帕米的PDT处理组内牙菌斑内致龋菌存活数量有上升趋势。其中先加入维拉帕米后加入光敏剂PDT处理组牙菌斑内致龋菌存活数量显著性上升(P<0.05),抑菌率仅为80.92%。结论 HMME-PDT可以通过有效抑制致龋菌的生长而起到防龋的作用。细菌外排泵抑制剂对HMME-PDT抑制牙菌斑生物膜内主要致龋菌有抑制作用。

Objective To Study the impact of the efflux pump-inhibitor,verapamil,on the cariogenic bacteria in dental plaque biofilms in the photodynamic therapy using hematoporphyrin monomethylether as photosensitizer. Methods The dental plaque biofilm models were established with streptococcus mutans,streptococcus sanguis,eosinophilic lactobacillus and actinomyces viscosus.By the order to add verapamil and photosensitizer in the PDT process,five groups were created： Group A,in which cells were incubated with photosensitizer and verapamil simultaneously;Group B,in which cells were incubated with verapamil before photosensitizer,Group C,in which cells were incubated with photosensitizer before verapamil;Group D,in which cells were given only PDT;and Group E,the saline-treated group.After the laser irradiation,plate count of bacteria was obtained to evaluate the vitality of the dental plaque bacteria after the PDT. Results The reduction of living cariogenic bacteria（CFU/mL） in plaque biofilms was much more distinctive（P〈0.05） in the sole PDT group than in the saline-treatment group,showing a bactericidal rate up to 94.92%.The comparison between Group B and Group D indicated a significant upward trend in the number of living cariogenic bacteria（P〈0.05）,and the sterilizationrate of the latter was 80.92%. Conclusions HMME-PDT inhibits effectively the growth of cariogenic bacteria and bacterial efflux pump plays an extremely important role in the process.