转录因子CCAAT／增强子结合蛋白α在银屑病皮损中的表达及意义

Expression of the transcription factor CCAAT/enhancer-binding protein alpha in psoriatic lesions and its significance

目的探讨转录因子CCAAT，增强子结合蛋白α（c／EBP—d）在寻常性银屑病皮损中的表达及与角质形成细胞异常增殖及皮损严重程度间的相关性。方法用免疫组化二步法及Westem印迹检测30例寻常性银屑病患者皮损和30例健康对照皮肤的表皮中C／EBP-α。免疫组化法检测Ki-67的表达，并根据Ki-67阳性表达数量计算增殖指数，Pearson相关分析法分析寻常性银屑病皮损中C／EBP-α的表达水平与角质形成细胞Ki一67增殖指数及银屑病皮损面积和严重程度指数（PASI评分）间的相关性。结果C／EBP—a主要在角质形成细胞胞质中表达，寻常性银屑病皮损中C／EBP—d的表达较健康对照皮肤明显下调（t=7．82，P〈0．05）。Ki-67主要在角质形成细胞胞核中表达，寻常性银屑病皮损中角质形成细胞的增殖指数明显高于健康对照皮肤（t=4．54，P〈0．05）。经Pearson相关分析，寻常性银屑病皮损中C／EBP-α表达水平与增殖指数呈负相关，与PASI评分呈负相关。Western印迹结果亦显示，C／EBP-α在银屑病皮损处的表达量显著下调。结论C／EBP—α在寻常性银屑病皮损中表达下调，可能参与了寻常性银屑病的发病过程。

Objective To detect the expression of the transcription factor CCAAT/enhancer-binding protein alpha （C/EBP-α） in the epidermis of psoriasis vulgaris lesions, and to investigate its correlation with abnormal keratinocyte proliferation and disease severity. Methods Biopsy specimens were obtained from the lesions of 30 patients with psoriasis vulgaris and normal skin of 30 healthy human controls. A two-step immunohistochemical procedure was performed to detect the expressions of C/EBP-α and Ki-67 in these specimens, and Western blot to quantify the expression of C/EBP-α. The proliferation index of keratinocytes was calculated according to the expression intensity of Ki-67. Statistical analysis was carried out by using the SPSS 17.0 software, and Pearson correlation analysis was conducted to assess the relationship of C/EBP-αexpression level with proliferation index of keratinocytes and psoriasis area and severity index （PASI） score. Results C/EBP-α was predominantly expressed in the cytoplasm of keratinocytes, while Ki-67 in the nuclei of keratinocytes. Compared with the normal skin, the psoriatic lesions showed a significantly lower expression of Ki-67 （t = 7.82, P 〈 0.05）, but higher proliferation index of keratinocytes （t = 4.54, P 〈 0.05）. The expression level of C/EBP-α was negatively correlated with the proliferation index of keratinocytes and PASI score in the patients （both P 〈 0.05）. Western blot also showed an obvious decrease in the expression of C/EBP-ot in psoriatic lesions. Conclusions The expression of C/EBP-α is decreased in lesions of psoriasis vulgaris, which might be involved in the pathogenesis of psoriasis vulgaris.