中文摘要：

背景与目的：研究昆布提取物（thallus laminariae PE，TLPE）在体外对耐药细胞B-MD-C1（ADR^＋／＋）的逆转作用，深入探讨TLPE逆转肿瘤多药耐药的机制。材料与方法：MTT法检测昆布提取物对耐药细胞B-MD-C1（ADR^＋／＋）的逆转作用，采用免疫细胞化学方法及流式细胞术检测P-gp蛋白表达的变化。用RT-PCR法检测TLPE作用前后B-MD-C1（ADR^＋／＋）细胞中多药耐药基因（MDR1）的表达水平。结果：昆布提取物在体外对B-MD-C1（ADR^＋／＋）有逆转作用，逆转倍数为4．65；免疫细胞化学方法显示，TLPE作用后，B-MD-C1（ADR^＋／＋）细胞P-gp的表达降低；流式细胞术结果显示，TLPE处理后细胞的荧光表达量降低，且与TLPE浓度呈依赖性；RT-PCR结果表明，TLPE可以使B-MD-C1（ADR^＋／＋）细胞的MDR1 mRNA表达减弱。结论：昆布提取物具有逆转B-MD-C1（ADR^＋／＋）的作用，其逆转作用与降低P-gp的表达有关，具有临床应用前景。

英文摘要：

BACKGROUND ＆ AIM： To investigate the reversing effect of Chinese drug thallus laminariae PE on drug resistance B-MD-C1（ADR ^＋/＋） cell line, and to identify the mechanism of TLPE in reversing the multidrug resistance. MATERIALS AND METHOS： MTT assay was used to determine the reversing effect of TLPE and reversal fold; cytoimmunochemistry and flow cytometry were used to assess the expression of P-gp in the level of protein. RT-PCR was used to detect the level of MDR1 gene treated by TLPE. RESULTS： TLPE had reversing effect on B-MD-C1（ADR^＋/＋）in vitro and the reversal fold was 4.65. Cytoimmunochemistry showed that TLPE could decrease the expression of P-gp. Flow cytometry showed that TLPE could decrease the expression of P-gp with dose-dependence. RT-PCR suggested that TLPE could reduce the MDR1 gene of B-MD-C1（ADR ^＋/＋）. CONCLUSION： TLPE could exert reversing effect in B-MD-C1 （ADR ^＋ /＋） by decreasing the expression of P-gp.