RESUMO
The histopathologic changes characteristic of psoriasis might be related to suppressed apoptosis. P53 and Bcl-2 proteins play a central role in the regulation of apoptaosis. Skin biopsies were obtained from non-lesional and lesional skin of 10 patients with generalized plaque psoriasis before and after treatment with topical calcipotriol ointment. P53 and Bcl-2 expression was evaluated using immunoperoxidase technique and apoptotic cells by TUNEL method After topical calcipotriol therapy, keratinocytes of psoriatic skin showed significant decrease of P53 [P=0.002] and increase of Bcl-2 [P=0.01] expression. On the other hand lymphocytes showed significant decrease of Bcl-2 [P=0.01]. There were no apoptotic cells before treatment but after calcipotriol therapy, apoptosis was more detected in keratinocytes than in lymphocytes. The results of the present study suggest that one of the actions of calcipotriol in psoriasis might be exerted through induction of apoptosis especially of keratinocytes through a P53 independent- pathway. Meanwhile, suppression of Bcl-2 expression in lymphocytes may promote apoptosis of dermal lymphocytes leading to healing of psoriasis