冷常压等离子体对牙龈卟啉单胞菌抗菌作用的实验研究

Antibacterial effect of the cold atmospheric plasma on Porphyromonas gingivalis——an experimental study

目的评价冷常压等离子体(cold atmospheric plasma,CAP)对牙龈卟啉单胞菌(Porphyromonas gingivalis,P.g)的抗菌作用并观察其对P.g超微结构的影响。方法用CAP对接种在钛片表面的P.g进行处理,依据处理距离和处理时间将实验组分为5 mm 30 s组、5 mm 60 s组、9 mm 30 s组和9 mm 60 s组,对照组不进行CAP处理。通过平板菌落计数法观察各组P.g数量的变化,场发射扫描电子显微镜(SEM)观察各组钛片表面P.g的形态和分布,并通过透射电镜(TEM)观察处理前后P.g超微结构的变化。结果 CAP处理时间和处理距离对各组菌落数均有显著影响,且各实验组菌落数与对照组相比,差异均有统计学意义(均P <0.05)。SEM观察可见,随着CAP处理时间和距离的变化,菌体受到不同程度的破坏;5 mm 60 s组和9 mm 60 s组细菌溶解、破碎,几乎观察不到完整的细菌形态;对照组仍为完整的短杆状菌体结构。TEM观察可见,通过CAP处理,P.g细胞膜断裂、模糊不清,细胞质外溢,可观察到扭曲和完全分离的膜结构;对照组P.g菌体超微结构未发生明显改变,细胞壁、细胞膜及细胞质结构清晰。结论 CAP对P.g有较好的杀灭作用,并可引起P.g超微结构的变化,在一定范围内增加处理时间、缩减处理距离有助于增强抗菌效果。

Objective To evaluate the antibacterial effect of cold atmospheric plasma(CAP)on Porphyromonas gingivalis(P.g)and observe its effect on the ultrastructure of P.g. Methods P.g on the titanium sheet surface was treated with CAP. According to the treatment distance and treatment time,the experimental group was divided into 5 mm 30 s group,5 mm 60 s group,9 mm 30 s group and 9 mm 60 s group;the control group was not treated with CAP. After treatment,the quantity of P.g was observed by plate colony counting method,the morphology and distribution of P.g on the surface of each group were observed by scanning electron microscope(SEM),and the ultrastructure of P.g was observed by transmission electron microscope(TEM). Results The treatment time and treatment distance of CAP had significant influence on P.g colony number. Compared with the control group,there were statistically significant differences in the antibacterial effect of P.g in each CAP treatment group(P < 0.05). SEM showed that the bacteria were destroyed in varying degrees with the change of time and distance of CAP treatment;the bacteria in 5 mm 60 s group and 9 mm 60 s group were dissolved and broken,and almost no complete bacterial morphology could be observed. The P.g in control group was still a complete short rod cell structure.TEM showed that through CAP treatment,the cell wall and the cell membrane ruptured and blurred and cytoplasm overflowed,and the distorted and completely separated membrane structure could be observed. In control group,the ultrastructure of P.g cells did not change significantly,and the structure of cell wall,cell membrane and cytoplasm was clear. Conclusion The CAP can damage the ultrastructure of P.g and has a good antibacterial effect on P.g,which is increased with increasing the treatment time and reducing the treatment distance within a certain range.