摘要目的 探讨环境污染物2,3,7,8-四氯二苯并二恶英(TCDD)影响人皮脂腺细胞的细胞色素P4501A1 (CYP1A1)分子信号途径及氯痤疮的发生机制.方法 实时荧光PCR研究10 nmol/L TCDD作用SZ95人皮脂腺细胞2h后CYP1A1 mRNA表达的变化；细胞免疫组化和斑点印迹法研究10 nmol/L TCDD作用SZ95人皮脂腺细胞3d后蛋白表达变化情况.结果 实时荧光PCR研究显示,CYP1A1 mRNA在SZ95人皮脂腺细胞呈低量表达,在10 nmol/L TCDD作用下,CYP1A1 mRNA表达增强了5.622倍,差异有统计学意义(P＜0.05).细胞免疫组化显示,CYP1A1蛋白在SZ95人皮脂腺细胞核及胞质中低量表达,在10 nmol/L TCDD作用下表达明显增强.斑点印迹法证实,10 nmol/LTCDD作用于SZ95人皮脂腺细胞3d后CYP1A1蛋白相对定量值(4.233±0.252)显著高于未加药的阴性对照组(0.123±0.208),差异有统计学意义(P＜0.05).结论 CYP1A1 mRNA和蛋白在SZ95人皮脂腺细胞上呈低量表达,但在TCDD作用下表达被激活,体外证明CYP1A1是TCDD影响人皮脂腺细胞异常分化的AhR下游靶位基因之一.

abstractsObjective To estimate the effect of the enviromental pollutant 2,3,7,8-tetrachlorodibenzo-pdioxin (TCDD),a representative of the dioxin family,on the expression of cytochrome P4501A1 (CYP1A1) in cultured human immortalized SZ95 sebocytes in vitro,so as to improve understanding of the pathogenesis of chloracne.Methods SZ95 sebocytes were cultured with or without the presence of 10 nmol/L TCDD for two hours or three days.Real time fluorescence-based PCR was performed to quantify the mRNA expression of CYP1A1,immunohistochemistry and Western blot to determine the expression level of CYP1A1 protein,in the SZ95 cells.Chi-square test was done to compare the protein and mRNA expressions of CYP1A1 between untreated and treated SZ95 cells.Results Real time PCR showed that the mRNA expression of CYP1A1 was low in SZ95 sebocytes,and increased by 5.622 times after 2-hour treatment with TCDD(P ＜ 0.05).Immunohistochemistry revealed a weak expression of CYP1A1 protein in the cytoplasm and nuclei of untreated SZ95 sebocytes,which was also significantly enhanced by the TCDD treatment.Western blot results showed that the relative expression level of CYP1A1 protein was 4.233 ± 0.252 in SZ95 sebocytes treated by TCDD for three days,significantly higher than that in untreated sebocytes(0.123 ± 0.208,P ＜ 0.05).Conclusions There is a low expression of CYP1A1 mRNA and protein in SZ95 sebocytes,which can be upregulated by TCDD,suggesting that the CYP1A1 gene is a downstream target of the aryl hydrocarbon receptor responsible for the abnormal differentiation of human sebocytes.