An Experimental Study On Effectiveness And Safety Of Modified ALA-PDT Therapy In Rabbit Ear Model With Acne

Objective: By establishing the rabbit ear model with acne andcomparing the efficacy and adverse events of traditional5-Aminolevulinic acidphotodynamic therapy(ALA-PDT) with red light and ALA-PDT internalradiotherapy imported by red light optical fiber（modified ALA-PDT）in rabbitear model with acne, we tried to prove the effectiveness and safety of modifiedALA-PDT, and thus providing a more detailed and better way for clinicalALA-PDT therapy on acne. Methods:25clean grade male rabbits weightingabout2kgs at the age of12weeks were selected and numbered. Among these25rabbits,20were randomly selected to establish rabbit ear model with acneby Kligman method.10ears of the left5rabbits went into the vacuity controlgroup only used to prove the rabbit ear model established successfully. After thesuccess of modeling，experimental control study was used．20model rabbitswere randomly divided into the treatment group1, the treatment group2, thetreatment group3and the treatment group4，10rabbit ears for each group. Thetreatment group1was given ALA-PDT internal radiotherapy imported by redlight optical fiber, namely: After an external application of a50%ALAphotosensitizer on the rabbit ears, according to a wavelength of630nm, andoutput power of5mw/cm2standard, the red light was imported by the opticalfiber head about2mms into the targeted rabbit ear acne lesions to implementan internal radiation for15minutes. The treatment group2was given15 minutes of traditional ALA-PDT red light irradiation for one-time. Thetreatment group3was given15minutes of red light radiation imported by anoptical fiber into the targeted lesions, but without an external application of a50%ALA photosensitizer. The treatment group4was not given any treatment.These syptoms such as flicking ears, twisting the body, digging with claws andscreaming and their frequencies were observed and recorded during the periodof being treated. These observe adverse events including the adverse reactionssuch as erythema, edema, desquamation, etc. around the targeted rabbit ear acnelesions and the state of rabbits such as falling ill or death apart from acne wereobserved and recorded after the treatment. The macroscopic observation, thebiopsy of targeted rabbit ear acne lesions and its surrounding skins, and theobservation of histologic changes for each group were did and recorded atdifferent times such as before the treatment,14days,30days and45days afterthe treatment. Finally the relevant datas were integrated and analyzedstatistically by SPSS17.0. Results:1.There were macroscopic observationresults such as blackhead, pimples, pustules, etc. and histologic observationresults such as epidermal thickening, hyperkeratosis, hair follicle to expandingand keratosis substances increased density, sebaceous glands expanding andinflammatory cell infiltration, etc. on the rabbit ear model with acne. Thesewere similar with the performance of human acne.2.The effectiveness of themodified ALA-PDT: The efficacy on treating rabbit ear model with acne was allgotten by the macroscopic observation, histologic observation and efficacy rate comparison in the treatment group1, the treatment group2, the treatment group3and the treatment group4as follows:①At14days after treatment, theefficacy rate with four groups was arranged from high to low: the treatmentgroup1(100%)＞the treatment group2(60)＞the treatment group3(40%)＞thetreatment group4(20%). The efficacy rate in treatment group1was obviouslyhigher than that in the other three treatment groups (P＜0.05), and there was nostatistics significance on the efficacy rate discrepancy among the treatmentgroup2, the treatment group3and the treatment group4（P＞0.05）.②At30days after treatment, the efficacy rate with four groups was arranged from highto low: the treatment group1, the treatment group2(the same:100%)＞thetreatment group3(88%)＞the treatment group4(60%). There was no statisticssignificance on the efficacy rate discrepancy among the treatment group1, thetreatment group2and the treatment group3（P＞0.05）, but the efficacy rate inthe other three treatment groups was all obviously higher than that in thetreatment group4(P＜0.05).③At45days after treatment, the efficacy rate inthe treatment group1, the treatment group2and the treatment group3wassame(100%) and higher than that in the treatment4(80%), but there was nostatistics significance on the efficacy rate discrepancy among the four treatmentgroups（P＞0.05）.3.The safety of the modified ALA-PDT: There were theadverse events observed among all four treatment groups.①During the periodof being treated, the frequencies of symptoms with four groups were arrangedfrom high to low: treatment group2（126）＞the treatment group1（47）＞the treatment group1（37）＞the treatment group1（7）. The frequencies in thetreatment group2was obviously higher than that in the other three treatmentgroups.②After the treatment, the adverse events rate with four groups wasarranged from high to low: treatment group2（90%）＞the treatment group4（40）＞the treatment group1（20%）＞the treatment group1（10%）. Theadverse events rate in the treatment group2was obviously higher than that inthe other three treatment groups (P＜0.05), but the adverse events rate in thetreatment group1was obviously lower than that in the treatment group2(P＜0.05) and close with that in the treatment group3and the treatment group4（P＞0.05）. Conclusions:1.Rabbits ears models of acne can be successfullyestablished by Kligman method.2.There is the similar curative effect ontreating rabbit ear model with acne between the modified ALA-PDT and thetraditional ALA-PDT, prompting it is effective for the modified ALA-PDT.3.There is higher tolerance and lower adverse events rate on treating rabbit earmodel with acne with the modified ALA-PDT than that with the traditionalALA-PDT, promting it might be higher safety for the modified ALA-PDT.