Effects Of 5-Aminolevulinic Acid In The Photodynamic Photorejuvenation Therapy Of Intense Pulsed Light

ObjectivesEvaluate the effects of 5-aminolevulinic acid (ALA) in the photorejuvenation therapy of intense pulsed light. Try to explore the possible mechanism of the effects and potential risks of this therapy, and supply laboratory and theoretical supports for the application of photodynamic therapy in the cosmetic skin rejuvenation field.Methods80 hairs removed female Kunming mice (six months old) were randomly divided into 4 groups:negative control group, ALA group, IPL irradiation group, ALA+IPL irradiation group (with 20 in each group). After they were been treated accordingly, we record the changes of the gross anatomy and microscopic structure of the skin, and the changes of collagenⅠ/Ⅲ, elastic collagen, transforming growth factor-β(TGF-β). Compare the differences among the groups, and try to find the possible relevancies between these changes.Results1. The minimum erythema dose of the ALA+IPL irradiation group was lower than the IPL irradiation group (P<0.05).2. The thickness of the dermis of the ALA+IPL irradiation group was thicker than the IPL irradiation group (P<0.05) (Day 7).3. The improvement of the disorder degree of collagen I of the ALA+IPL irradiation group was more significant than the IPL irradiation group (Day 14, Day 28).4. The content of collagenⅢof the ALA+IPL irradiation group was higher than the IPL irradiation group (Day 7, Day 14, Day 28).5. The content of elastic fibers had no significant difference between the ALA+IPL irradiation group and the IPL irradiation group.6. The expression of TGF-βof the ALA+IPL irradiation group was higher than the IPL irradiation group (P<0.05) (Day 3).Conclusion1. Photosensitizer ALA could significantly reduce the radiation dose of IPL rejuvenation and improve the efficiency of collagen remodeling of IPL. Therefore, it could effectively reduce the againg rate and the potential risks of IPL rejuvenation treatment.2. The effects of ALA in improving IPL's efficiency of collagen remodeling and regeneration may be related to the increase of TGF-βexpression in epidermis and hair follicle.