| Objective Evaluating the efficacy of antimicrobial photodynamic therapy (APDT) on Candida albicans by Phenothiazine dyes in vitro in order to provide theoretical basis for clinical choosing the most efficient and properest photosensitizer. Investigating the role of APDT in the treatment of oral Candida albicans in HIV-infected patients.Methods The first part is the in vitro experiment. Fungus suspension of Candida albicans standard strain DAY286 was prepared to a concentration of 107 colony-forming units(CFU)/ml. The study was divided into 4 groups. (1)The blank control group: the fungus suspension was without photosensitizers(PSs) and illumination. (2) The APDT group: the fungus suspension was mixed with different concentrations of phenothiazine photosensitizers such as toluidine blue O(TBO), methylene blue (MB) ,new methylene blue (NMB), 1,9-dimethylmethylene blue ( DMMB ), and incubated in the dark at room temperature for 30 min. Then the mixed suspension was exposed to the different wavelength but the same energy of illuminant according to the experiments requested. (3) The light group: the fungus suspension without PSs was exposed to the same energy of illuminant as the APDT group. (4)The photosensitizer group: the fungus suspension was incubated with different PSs(MB, TBO, NMB and DMMB ) for 30 min, but without illumination. The survival rate of fungus was calculated with counting CFU after different treatments.The second part is clinical trials. According to the result of above experiment choosing the most effeicent phenothiazine dyes of DMMB-mediated APDT on Candida albicans in vitro. The study subjects is AIDS with oral Candida albicans. Before the treatment , subjects gargled 10s with 0.1 mmol / L phosphate buffer solution (PBS) and then received the DMMB of 1.2mmol/L for incubation 3 min rubbed oral mucosal lesions with sterile cotton swab. Following on incubation, subjects received a single session of low-level laser irradiation for 3 days ,with wavelength 635nm and energy power 10J/cm2 for 30min per days. By using the direct microscopy method determination of Candida albicans cell number before and after the treatment.Results (1) In this study all Phenothiazine dyes(MB, TBO, NMB and DMMB) showed different APDT effects against Candida albicans , the survival rate being 78.38%?68.47%?62.37%?0.0001% , respectively, at the concentration of 15?mol/L (P<0.05) . The DMMB-mediated photodynamic inactivation of Candida albicans was increased with the incresing of the concentration from 0.1?mol/L to 15?mol/L (P<0.05) . At the concentrations from 5?mol/L to 100?mol/L, the APDT effects of TBO and MB showed concentration dependent killing(P<0.05). There were no statistically significant difference in the blank control group, the light group and the photosensitizer group between each other(P>0.05).(2) DMMB-mediated APDT on oral Candida albicans in HIV-infected patients in the treatment of first times, the number of oral Candida albicans inactivated rate was 49.34% compared with before treatment? After the treatment of second and third times, the oral Candida albicans inactivated rate,respectively, was 35.58% and 24.45% compared with the baseline before treatment?There were statistically significant difference that the number of Candida albicans in the group of before and after treatment between each other.Obvious adverse reactions and sequelae were not found in all subjects.Conclusions (1)DMMB is the most effective phenothiazinium dye against Candida albicans in vitro. In a certain range of concentration, the APDT effects of DMMB? TBO and MB showed concentration dependent killing ?(2) DMMB-mediated APDT can kill oral Candida albicans in HIV-infected patients. |
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