Hagemann I, Proksch E
Department of Dermatology, University of Kiel, Germany.
Acta Derm Venereol. 1996 Sep;76(5):353-6. doi: 10.2340/0001555576353356.
The mechanisms of action of urea-containing ointments in the treatment of eczema, ichthyosis and psoriasis are only partly known and related to proteolysis and keratinolysis. In this study, we have examined the effects of topical urea on epidermal proliferation and differentiation in 10 patients with psoriasis. Plaque type lesions were treated for 2 weeks with an ointment containing 10% urea, with the vehicle alone, or left untreated. Clinical score, hydration of the stratum corneum, transepidermal water loss (TEWL), and immunohistochemical studies were performed. Epidermal proliferation was assessed using the Ki-S3 proliferation-associated nuclear antigen. For epidermal differentiation antibodies against involucrin and against keratins CK 5, 6, 17 and CK 1, 5, 10, 14 were used. The patients showed a reduction of the clinical score (> 50%), a 2-fold increase in stratum corneum hydration (p < 0.01), and a small decrease in TEWL (N.S.) on the urea- treated compared to the untreated site. Light microscopy studies revealed a 29% reduction in epidermal thickness (p < 0.01); epidermal proliferation was decreased by 51% (p < 0.005). The altered expression of involucrin and of cytokeratins (reduction of CK 5, 1 and 10 and induction of CK 6 and 17) was partially reversed. The ointment base also improved psoriasis, but urea was significantly better than the vehicle (urea: 40% reduction in epidermal proliferation vs. vehicle). In summary, these studies show that urea influences epidermal proliferation and differentiation in psoriasis.
含尿素软膏治疗湿疹、鱼鳞病和银屑病的作用机制仅部分为人所知，且与蛋白水解和角质溶解有关。在本研究中，我们检测了外用尿素对10例银屑病患者表皮增殖和分化的影响。对斑块型皮损分别用含10%尿素的软膏、单纯基质或不进行治疗，持续处理2周。进行了临床评分、角质层水合作用、经表皮水分流失（TEWL）及免疫组化研究。使用Ki-S3增殖相关核抗原评估表皮增殖。针对内披蛋白以及角蛋白CK 5、6、17和CK 1、5、10、14使用了表皮分化抗体。与未处理部位相比，尿素处理部位的患者临床评分降低（>50%），角质层水合作用增加2倍（p<0.01），TEWL略有降低（无统计学意义）。光学显微镜研究显示表皮厚度降低29%（p<0.01）；表皮增殖降低51%（p<0.005）。内披蛋白和细胞角蛋白表达的改变（CK 5、1和10减少，CK 6和17增加）部分得到逆转。软膏基质也能改善银屑病，但尿素的效果明显优于基质（尿素：表皮增殖降低40%，而基质为对照）。总之，这些研究表明尿素可影响银屑病患者的表皮增殖和分化。
