Effect Of Q-switched Nd:YAG1064nm Laser On The Cell Activity,protease Activity And Structure Of Malassezia Furfur

Background:Malassezia folliculitis is a common skin disease,and Malassezia furfur is one of the main pathogenic fungus.Since the infection site of Malassezia folliculitis is deep,the traditional topical or oral antifungal drugs are difficult to treat and subject to relapse.Recently,the application of photoelectricity treating Malassezia folliculitis has been reported at domestic and abroad,which has obtained good curative effect,providing a new method for the treatment of Malassezia folliculitis.According to the characteristics of Q-switched Nd:YAG1064nm laser,we speculate that Malassezia can be damaged,which can be one of treatments for Malassezia folliculitis.Objective:To investigate the effect of Q-switched Nd:YAG1064nm laser on the cell activity,protease activity and ultrastructure of M.furfur at different energy density.This study provides experimental basis for the treatment of Malassezia folliculitis with Q-switched Nd:YAG1064nm laser,as well as a new idea for the traditional treatment of fungal skin diseases.Methods:We used the standard strain of M.furfur,which was irradiated by Q-switched Nd:YAG1064nm laser.In the experimental group,M.furfur was irradiated with laser at various energy density 15.9J/cm~2,19.1 J/cm~2,22.2J/cm~2,25.4J/cm~2,28.7J/cm~2(divided as group B,C,D,E,F),while M.furfur without laser irradiation served as the control(group A).(1)Recording the colony diameter daily and plotted the growth curve,and evaluating the cell activity through the colony-forming counting.(2)To detect protease activity of group A,B,D,F through the whole milk medium.(3)To observe the ultrastructure of M.furfur in each group through transmission electron microscope.Results:(1)The growth curve showed the condition of growth and difference in each group.There is no significant difference between group B and A(t_b=1.062,P>0.05)comparing with the colony diameter,while the group C,D,E and F were inhibited in different degrees(t_c=3.042,t_d=3.060,t_e=5.082,t_f=6.396,P<0.05).And laser induced a dose-dependent inhibition of colony diameter(R=-0.671,P<0.05).The result of colony-forming units showed that there is no significant difference between group B and group A(t_b=1.637,P>,0.05),while group C,D,E and F showed different degrees of reduction(t_c=13.991,t_d=18.126,t_e=24.189,t_f=24.939,P<0.05),and laser induced a dose-dependent reduction of colony-forming units(R=-0.906,P<0.05).(2)The protease activity of group A is the highest.There was no significant difference in protease activity between group B and group A(t_b=1.456,P>0.05),while protease activity was significantly decreased in group D and F(t_d=7.606,t_f=37.908,P<0.05),and laser induced a dose-dependent inhibition of protease activity(R=-0.942,P<0.05).(3)The structure of group A is unbroken,which is almost similar to group B,and we can observed the structure was obviously damaged in group C,D,E and F.In addition,laser induced a dose-dependent disruption of M.furfur structure.Conclusion:There is no significant effect of the low energy density Q-switched Nd:YAG1064nm laser on the cell activity,protease activity and ultrastructure of M.furfur.In contrast,the high and medium energy density Q-switched Nd:YAG1064nm laser can inhibit the cell activity,protease activity and destroy the ultrastructure of M.furfur,and the laser induced a dose-dependent effect on M.furfur.