The Biological Effect Of Topical 5-Aminolevulinic Acid Photodynamic Therapy In Optimizaed Incubation Period On Treating Psoriasis Model Of Guinea Pig

Objective:1.Experimental observation and investigation of topical 5-Aminolevulinic Acid Photodynamic Therapy (ALA-PDT) treating psoriasis vulgaris model of guinea pigs'ear. This study examines the time course of porphyrin metabolite formation after topical application of 5-ALA and observes the change of the content of PpIX,T cell subsets (CD4+,CD8+) during the therapy.2. In this study the biological effects of ALA-PDT on T cell subset and cytokine in the model of psoriasis vulgaris were investigated, which can provide theoretical basis for topical application in the clinic.Methods:Establishing psoriasis vulgaris model of guinea pigs'ear by application of propranolol. After the success of modeling each group were observed lesions healing with naked eye, changes of lesions epidermal thickness and pathological score with HE staining before the treatment and at day 7,14,21,28 after the treatment. Immunohistochemical staining method was used to observe and analyze the changes of Proliferating Cell Nuclear Antigen (PCNA) and T cell subsets (CD4+,CD8+).Results:1. Effect of different ALA Incubation time on PpIX:The mean of the content of PpIX in topical lesion of each group were increased with incubation time and the fastest period is 1h-3h.2. Macroscopic and HE staining observation:The shortest recovery time was ALA application 15h group and the average recovery time was 11d, that shorter than other group.3. The results of IHC staining showed:The mean of the content of CD4+and CD8+ T cell in topical lesion of each group were decreased with time. The ALA application 15h group was obviously more than ALA application 1h group, ALA application 3h group and model control group.4. Pigmentation was observed in 30% animals of 15h group after treatment, while no cases in other groups.Conclusion:1. Topical ALA-PDT is effective for psoriasis vulgaris model of guinea pigs'ear and the ALA incubation time correlated nagetively with the lesions healing time.2. The content of PpIX in topical lesions has positive correlation with the ALA incubation time and the fastest rate accurring between 1h-3h after incubation.3. The ALA-PDT can inhibite the lesion epidermal cell abnormal proliferation, reduce the CD4+ and CD8+ T cell level and it's level correlated positively with the content of Ppâ…¨in the topical lesions.