Kemény L, Michel G, Arenberger P, Ruzicka T
Department of Dermatology, University of Munich, Germany.
Acta Derm Venereol. 1993 Feb;73(1):37-40. doi: 10.2340/00015555733740.
Dithranol is highly effective in the treatment of psoriasis, but the exact mechanism of action is not known. Since persistent expression of epidermal growth factor (EGF) receptors in psoriatic epidermis is assumed to have pathogenetic significance, we have studied the effects of dithranol on EGF binding to the human epidermal cell line SCL-II. After treatment of cells with dithranol or its therapeutically inactive oxidation product, danthrone, radioligand binding assays were performed with 125I-EGF. In therapeutically active concentrations (0.25-1 micrograms/ml) dithranol induced a decrease in EGF binding in a dose dependent manner. Danthrone was inactive. The inhibition occurred after a latency period of 6 h and reached its maximum at 24 h. At the concentration of 1 microgram/ml, the drug led to approximately a 70% decrease in the number of specific high-affinity EGF receptors (Bmax), whereas receptor affinity (Kd) showed no change. The down-regulation of EGF receptors on epidermal cells by dithranol may contribute to its antipsoriatic action.
地蒽酚对银屑病的治疗效果显著，但其确切作用机制尚不清楚。鉴于银屑病表皮中表皮生长因子（EGF）受体的持续表达被认为具有致病意义，我们研究了地蒽酚对EGF与人表皮细胞系SCL-II结合的影响。用地蒽酚或其治疗无活性的氧化产物丹蒽醌处理细胞后，用125I-EGF进行放射性配体结合试验。在治疗活性浓度（0.25-1微克/毫升）下，地蒽酚以剂量依赖方式诱导EGF结合减少。丹蒽醌无活性。抑制作用在6小时的潜伏期后出现，并在24小时达到最大值。在1微克/毫升的浓度下，该药物导致特异性高亲和力EGF受体数量（Bmax）下降约70%，而受体亲和力（Kd）没有变化。地蒽酚对表皮细胞上EGF受体的下调可能有助于其抗银屑病作用。
