The Dose-Effect Relationship Of LED Phototherapy In The Treatment Of Helicobacter Pylori Infection

Objective:.With the continuous progress of LED light source technology,the compact and lightweight LED light source has become an ideal choice for implantable or implantable phototherapy equipment in vivo.The purpose of this study is to explore the dose-effect relationship between LED light-mediated PDT and PBM in the treatment of H.pylori infection,and to identify the optimal treatment scheme of LED-PDT and LED-PBM for clinical treatment of H.pylori infection.To provide reference for the development of LED capsule robot against H.pylori infection in digestive tract.Methods:(1)Different types of LED light sources matching bacterial suspension experiment,biofilm experiment and animal experiment were designed and made,and tested and characterized,so that all the light sources could meet the needs of the corresponding experiments.(2)At the bacterial suspension level,the concentration of photosensitizer(2,4,6,8,10 μg/mL)was set.LED light intervention was carried out on H.pylori suspension with the following parameters:wavelength(405,530,630 nm),optical power density(15 mW/cm2 and 30 mW/cm2)and light dose(0,3.6,7.2,10.8,14.4,18.0 J/cm2).The effect and dose-effect relationship of LED-PDT and LED-PBM against H.pylori infection were studied,and suitable optical parameters were selected.(3)At the biofilm level,6 μg/mL photosensitizer concentration,15 mW/cm2 optical power density and three wavelengths(405,530,630 nm)were set to interfere with H.pylori biofilm.To evaluate the anti-infection effect of LED-PDT and LED-PBM on H.pylori.(4)The H.pylori infection model of SD rats was established at the animal level.The photosensitizer concentration was 6 μg/mL,the illumination dose was 7.2 J/cm2,and the wavelength was 405 nm,530 nm and 630 nm,respectively.HE staining,anti-H.pylori,PCNA,EGFR and other immunohistochemical staining were used to evaluate the therapeutic effect.Results:(1)At the level of bacterial suspension,the bacteriostatic effect of PDT was better than PBM.Among the wavelength parameters,405 nm had the best antibacterial effect.Among the parameters of light dose,the bacteriostatic effect was positively correlated with the light dose(except 630 nm),but when the bacteriostatic rate entered the plateau,the bacteriostatic effect did not increase with the increase of light dose.The influence of power density on bacteriostatic effect was closely related to wavelength and light dose,and the influence of photosensitizer concentration on bacteriostatic effect was also restricted by wavelength parameters.Based on the results of bacterial suspension experiment and considering the actual clinical situation,the optimal concentration of photosensitizer was selected as 6 μg/mL,which was used in biofilm and animal experiments.The lowest light dose of 7.2J/cm2 when the bacteriostatic rate reached more than 99%was used as the reference of light dose in animal experiments.(2)At the biofilm level,the bacteriostatic effect of PDT was still significantly better than that of PBM,and the bacteriostatic effect of 405 nm was stronger than that of other wavelengths,which was consistent with the results obtained by the bacterial suspension experiment.The bacteriostatic rate of biofilm was 97.81±1.79%at the same maximum dose as the bacterial suspension test.(3)At the animal level,two kinds of optical therapy have the therapeutic effect on H.pylori infection,and the PDT group and the 405 nm/630nm mediated PBM group have the best therapeutic effect,and the complete eradication of H.pylori,the therapeutic effect is equivalent to the clinical standard gastric triple therapy.At the same time,LED phototherapy does not damage gastric mucosa,but also can inhibit the excessive proliferation of gastric mucosa cells caused by H.pylori infection to avoid the risk of cancer.Conclusion:In this study,the effects of LED-PDT and LED-PBM against H.pylori infection were verified,and the optimal optical parameters(concentration of photosensitizer 6 μg/mL,optical power density 15 mW/cm2,illumination dose 7.2 J/cm2 and wavelength 405 nm or 630 nm)were selected.It will provide reference and basis for the clinical application of LED-PDT and LED-PBM in the treatment of H.pylori infection.