Investigation of anti-inflammatory and anti-proliferative activities promoted by photoactivated cationic porphyrin.

Background: Photodynamic therapy (PDT) is a technique that uses light and a photosensitizer, converting local molecular oxygen into singlet oxygen, which eliminates a target unhealthy tissue. It has been increasingly used for the treatment of several diseases including skin disorders. Psoriasis is a chronic inflammatory skin disease expressing immune and hyperproliferative features.

Objective: This study aimed to evaluate the effect of the photosensitizer 5,10-diphenyl-15,20-di(N-methylpyridinium-4-yl)porphyrin (Di-cis-Py+) in in vivo models whereby some psoriasis-like parameters could be investigated.

Methods: The antiinflammation and antiproliferative activities of Di-cis-Py+ photoactivated was measured by myeloperoxidase (MPO) and N-acetyl-β-d-glucosaminidase (NAG) enzyme activity assay, measurement of IL-6, IL-1β and TNF-α levels, evaluation of proliferating cell nuclear antigen (PCNA) levels by immunohistochemistry and by Western blot.

Results: Treatment involving PDT and Di-cis-Py+ resulted in reduction of edema, cellular infiltration, proinflammatory cytokines, as well as reduced hyperproliferation of the epidermis. All the evaluated parameters were promoted by topical application of phlogistic agents and are similar to that observed in lesions of psoriatic skin.

Conclusion: The results shows the advantage of topical application, do not cause apparently photosensitivity and have effects comparable to dexamethasone, a first-line drug for the treatment of the disease.