Abstract: Objective To investigate apoptosis of psoriatic keratinocytes and the effects of retinoic acid and elemene on apoptosis of cultured keratinocytes. Methods Apoptosis of psoriatic keratinocytes and the effects of retinoic acid and elemene on apoptosis of cultured keratinocytes were studied with TUNEL method, flow cytometry and DNA fragmentation extraction. Results It was found that there were a large number of apoptotic cells throughout all layers of psoriatic epidermis in 19 of 28 patients and relatively small amount in upper epidermal layers in 9 of 28 patients. Retinoic acid at concentrations of 1,5,10,20μg/mL and elemene at 20,40,60,80μg/mL could induce apoptosis of cultured Colo-16 keratinocytes in vitro. Conclusion These results indicate that the number of apoptotic cells increased abnormally in psoriasis. Retinoic acid and elemene at certain concentrations could induce apoptosis of cultured Colo-16 keratinocytes in vitro.

Key words: Psoriasis, Apoptosis, Tretinoin, Elemene