Effect Of Nonthermal Plasma On Colonized Pseudomonas Aeruginosa On Skin Wound In Mice

Part I The nonthermal plasma suppresses the bacterial colonization on skin wound and promotes the wound healing in miceObjective To evaluate the effect of the nonthermal palsma on skin wound healing in BalB/c mice and try to find the possible mechanism.Methods Two 6-mm wounds were created on the back of each mouse (n=40) by using a punch biopsy. The mice were assigned randomly into two equal groups:group 1 as by nonthermal plasma getreated group and group 2 as control group. Wound healing of 10 mice per group was evaluated on the postoperative days (POD) 4,7,10 and 14 by percent wound closure.10 mice per group were euthanized on the postoperative days (POD) 1,4,7, 10,14,21,28 and 35. Both wounds were removed and routinely fixed and embedded in paraffin sections, stained with hematoxylin and eosin.Results A modified scoring system was used to evaluate the wounds. Significant differences were found in the results of histologic examination between the two groups in terms of acute inflammation on POD 7, amount of granulation tissue on POD 4 and 7, granulation tissue fibroblast maturation on POD 10, reepithelialization on POD 7 and 10, and neovascularization on POD 7 and 10 (P<0.05).Conclusion The nonthermal plasma positively affected the wounds healing in mice. And further study found that the nonthermal plasma can restrain the bacteria reproduction in vitro, which suggests that the facilitation of the wounds healing is connected with the suppression of bacterial colonization. Part II Effect of nonthermal plasma on the viability and expression of virulence factors in Pseudomonas aeruginosaObjective To study the effect of nonthermal plasma against Pseudomonas aeruginosa on the wound in mice, and its effect on the expression of virulence factors.Methods The suspensions of Pseudomonas aeruginosa PAO1 and PA0911, PA0912, PA0913 were added into the fluid nutrient medium of Pseudomonas aeruginosa(OD6oo=0.05), the elastase activity was detected by using Elastin Congo Red; pyocyanine quantification assay was performed by extraction with chloroform and hydrochloric acid orderly.Results The nonthermal plasma shown the bactericidal ability against Pseudomonas aeruginosa, and inhibited pyocyanine production, elastase activity of PA0911, PA0912, PA0913 compared with PAO1.Conclusions The nonthermal plasma can inhibit the expression of Pseudomonas aeruginosa virulence factors and weaken its viability. Partâ…¢Effect and mechanism of nonthermal plasma on the biofilm formation of Pseudomonas aeruginosaObjective To investigate the effects and possible mechanism of nonthermal plasma on the biofilm formation.Methods We use the modified plate culture method to establish the bilfilm model in vitro. biofilm quantification assay was carried out by staining with crystal violet and spectrophotometer assay. Semiquantitative RT-PCR was applied to determine the expression level of algD gene in PAO1 and PA0912.Results The biofilm of PAO1 was matured at 3th day, and PA0912 is not able to produce biofilm. In the whole period under observation, the expression level of algD gene of PA0912 was distinct lower than PAO1.Conclusions The nonthermal plasma can inhibit the biofilm formation of Pseudomonas aeruginosa, and the mechanism is probable concerned with the expression suppression of the alginate synthetic gene algD.