Objective To investigate the effects of high glucose on the expression of P-glycoprotein ( P-gp) and 5-Fu sensitivity in gastric cancer tissues and gastric cancer cell line SGC 7901.Methods The expression of P-gp from the gas-tric cancer tissues in 40 cases of patients with gastric cancer and 30 case of patients with type 2 diabetes mellitus combined with gastric cancer was detected by immunohistochemistry .Human gastric cancer cell line SGC 7901 was cultured and inter-vened by 1 000, 4 500 and 9 000 mg/L glucose (low-dose, medium-dose and high-dose glucose group).The cell total protein of each group was collected , the expression of P-gp protein in each group was detected by Western blotting , and the sensitivity of cells to 5-Fu was detected by MTT assay .Results The average optical density of P-gp in 40 cases of gastric cancer and 30 case of type 2 diabetes mellitus combined with gastric cancer was 0.0146 and 0.021 5 respectively ( P<0.01).The expression of P-gp in high-dose, medium-dose and low-dose glucose groups was 2.92 ±0.09, 2.53 ±0.09 and 1.56 ±0.09, respectively.Meanwhile, significant difference was found between every two groups (all P<0.01). MTT results showed that the sensitivity of gastric cancer cells to 5-Fu was decreased as the increased concentrations of glu-cose, especially in high-dose glucose group (P<0.01).Conclusion High glucose may promote the expression of P-gp protein in gastric cancer and gastric cancer cell line SGC 7901, thus reduce the sensitivity of gastric cancer cells to 5-Fu.%目的：探讨高糖环境对胃癌组织、胃癌SGC7901细胞株P-糖蛋白（P-gp）表达及5-氟尿嘧啶（5-Fu）敏感性的影响。方法选择胃癌患者40例、2型糖尿病合并胃癌患者30例，取手术切除的胃癌组织标本，采用免疫组化法观察胃癌组织中P-gp表达情况；取人胃癌SGC7901细胞株，体外培养，并给予1000、4500、9000 mg／L葡萄糖干预（分别设为低、中、高浓度组）。收集各组细胞的总蛋白，Western blotting法检测各组细胞中P-gp表达；MTT法检测各组细胞对5-Fu的敏感性。结果40例胃癌组织中P-gp的平均光密度值为0．0146，30例2型糖尿病合并胃癌组织中P-gp的平均光密度值为0．0215，二者比较P＜0．01。高浓度组P-gp的相对表达量为2．92±0．09，中浓度组为2．53±0．09，低浓度组为1．56±0．09，组间两两比较P 均＜0．01。随着葡萄糖浓度的升高，5-Fu 对胃癌SGC7901细胞的增殖抑制率逐渐下降，尤其以高浓度组效果最明显（ P＜0．01）。结论高糖环境可提高胃癌组织及胃癌SGC7901细胞株P-gp表达，从而降低胃癌细胞对5-Fu的敏感性。
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