Experimental Research On Topical 5-Aminolevulinic Acid Photodynamic Therapy In Treating Psoriasis Model Of Guinea Pig

Objective:Observe the efficacy of topical 5-Aminolevulinic Acid Photodynamic Therapy (ALA-PDT) treating psoriasis vulgaris model of guinea pigs' ear back.To research the feasibility of ALA-PDT treating psoriasis vulgaris,preliminarily discuss its mechanism of action.Provide the theoretics basis and steering mind for ALA-PDT treating psoriasis vulgaris.Method:10 of 60 healthy adult guinea pigs were randomly selected to be matrix control group,the remaining 50 established psoriasis vulgaris model of guinea pigs' ear back. After the success of modeling,the 50 guinea pigs were randomly divided into model control group,simple irradiation group,simple ALA group,once ALA-PDT treatment group and twice ALA-PDT treatment group.Model control group did not be disposed;Simple irradiation group only given irradiation;Simple ALA group only given ALA;The latter two groups irradiation with the semiconductor laser of wavelength 635nm,output power of 30mW and energy density 12J/cm~2 after adopting 20%ALA solution wet packing lesions for 4h,twice ALA-PDT treatment group had been the second treatment at day 7 after the first treatment.Each group were observed lesions healing with naked eye,changes of lesions epidermal thickness and pathological comprehensive score with HE staining,and changes of lesions epidermis PCNA positive with Proliferating Cell Nuclear Antigen(PCNA) immunohistochemical staining before the treatment,at day 7,14,21 and 28 after the treatment,adopt SPSS 13.0 to deal with statistics to the result.Result:Macroscopic observation:At day 7 after the treatment,guinea pigs' ear of ALA-PDT treatment group appeared swelling and thickening were reduced,scale reduced too;Model control group,simple irradiation group and simple ALA group were no significant change.From day 1 after the second treatment(that is day 8 after the first treatment), lesions subsided of twice ALA-PDT treatment group was significantly accelerater than the once ALA-PDT treatment group,the average recovery time was 13d,and the once ALA-PDT treatment group should be 16d,and there was significant difference between the two groups(P=0.000).Lesions subsided of model control group,simple irradiation group and simple ALA group were slowly,the average recovery time was respectively 28d,27d and 27d,there was significant difference compared with ALA-PDT treatment group(P=0.000),and there was not significant difference amang this three groups.In the irradiation of ALA-PDT,most animals were only mild discomfort or no systemic reaction,a small number of animals emerged irritability.In the course of treatment,lesions were no adverse reactions such as vesicle,exudates and so on,lesions were no scar and pigmentation after recovery.Observed by HE staining:At day 7 after the treatment,lesions epidermis of ALA-PDT treatment group began thinning,hyperkeratosis reduced,parakeratosis disappeared,the downward extension of apophysis improved,dermal inflammatory cells were reduced;Model control group,simple irradiation group and simple ALA group were no significant change.At day 14 after the treatment,lesions pathological changes of twice ALA-PDT treatment group was significantly improver than the once ALA-PDT treatment group. At day 21and day 28 after the treatment,lesions pathological changes of two groups was respectively recovered normal skin histology,that is,epidermal was humble,keratosis was mormal,the thickness of stratum spinosum was mormal,junctional of epidermal and dermis was leveling,dermis didn't have inflammatory cell infiltration.The lesions pathological changes of model control group,simple irradiation group and simple ALA group improved slowly,to day 28 after the treatment still can be seen thicker skin,a small number of inflammatory cells infiltration in the dermis.The analysis of variance of repeated measurement results reveals:the mean value of lesions epidermal thickness and pathological comprehensive score of each group were diminished with time,the decrease range of ALA-PDT treatment group was larger than model control group,simple irradiation group and simple ALA group,and from 7d after the treatment,the decrease range of twice ALA-PDT treatment group was obviously larger than once ALA-PDT treatment group.Observed by PCNA immunohistochemical staining:At day 7 after the treatment,lesions epidermis PCNA positive of ALA-PDT treatment group decreased,it is mainly on stratum basale and the middle and lower part of the stratum spinosum;Model control group,simple irradiation group and simple ALA group were no significant change.At day 14 after the treatment,lesions epidermis PCNApositive decrease of twice ALA-PDT treatment group was more significantly than the once ALA-PDT treatment group.At day 21and day 28 after the treatment,lesions pidermis PCNA positive decrease of two groups was respectively recovered normal,that is,PCNA positive is mainly on stratum basale,and rarely on stratum spinosum,The lesions epidermis PCNA positive decrease of model control group,simple irradiation group and simple ALA group were slowly,to day 28 after the treatment still can be seen that PCNA positive was on stratum basale and lower stratum spinosum.The analysis of variance of repeated measurement results reveals:the mean value of lesions epidermis PCNA positive rate of each group were diminished with time,the decrease range of ALA-PDT treatment group was larger than model control group,simple irradiation group and simple ALA group,and from 7d after the treatment,the decrease range of twice ALA-PDT treatment group was obviously larger than once ALA-PDT treatment group.Conclusion:1.Topical ALA-PDT treating psoriasis vulgaris model of guinea pigs' ear back has obvious efficacy,the efficacy of twice treatment is better than once treatment, and the tolerability of ALA-PDT treatment is well,side effects are small,it can be used as one of the selection methods of clinical treatment of psoriasis vulgaris.2.The possible mechanism of action that topical ALA-PDT treating psoriasis vulgaris model of guinea pigs' ear back is as follows:(1) inhibit lesion epidermal cell abnormal proliferation;(2) eliminate local lesion inflammatory reaction.