摘要目的:探讨高压氧（HBO）对人肺癌A549吉西他滨（Gem）耐药细胞的逆转作用及其作用机制。方法:采用体外低浓度梯度递增法构建Gem耐药A549细胞株（A549/Gem）模型。根据实验设计将A549/Gem耐药细胞株分为耐药对照组、高压氧组（HBO组）、Gem组及HBO联合Gem组（HBO+Gem组），处理方式分别为：不做处理，0.2 MPa HBO处理3 h，10.0 μmol/L Gem处理24 h，0.2 MPa HBO处理3 h后用10.0 μmol/L Gem处理24 h。CCK-8法检测A549/Gem耐药细胞的增殖能力，流式细胞术检测A549/Gem耐药细胞的凋亡水平，Western blotting实验检测A549/Gem耐药细胞凋亡蛋白、耐药蛋白及通道蛋白色素框同源蛋白6（CBX6）表达量的变化。结果:与其他3组比较，HBO+Gem组A549/Gem耐药细胞增殖能力明显受到抑制（ P<0.01）。HBO+Gem组A549/Gem耐药细胞凋亡率（32.4%）明显高于对照组（1.08%）、HBO组（5.42%）和Gem组（9.28%），差异均有统计学意义（ P<0.01）。与其他3组相比，HBO+Gem组凋亡蛋白Bcl-2表达量明显降低，Bad、caspase-3表达量明显升高，差异均有统计学意义（ P<0.01）；HBO+Gem组耐药P糖蛋白（P-gp）、多药耐药相关蛋白（MRP）表达量明显降低，差异均有统计学意义（ P<0.01）；HBO+Gem处理明显上调A549/Gem耐药细胞CBX6的表达（ P<0.01）。 结论:HBO联合Gem能够显著降低A549/Gem耐药细胞对Gem的耐药性，其主要作用机制是通过调控A549/Gem耐药细胞通道蛋白、耐药蛋白和凋亡相关蛋白的表达，促进A549/Gem耐药细胞凋亡而实现的。

abstractsObjective:To study the reversal effect and the mechanism of hyperbaric oxygen（HBO）on gemcitabine（Gem）-resistance of human lung cancer A549 cell lines.Methods:The A549 cell lines were exposed to stepwise escalating concentration of Gem in vitro until the Gem-resistant A549（A549/Gem）cell lines were developed. The CCK-8 and flow cytometry were used to detect the effect of HBO on the proliferation and apoptosis of A549/GEM cells，respectively，and western blot was used to detect the expression levels of apoptosis proteins，drug-resistant proteins，and the chromobox protein homolog 6（CBX6）in A549/GEM cells.Results:Compared with those in the control，HBO，and Gem groups，the proliferation of A549/GEM cells in the HBO + GEM group was significantly inhibited（ P<0.01）. The apoptosis ratio in the HBO + GEM group was 32.4%，which was much higher than those in the control（1.08%），HBO（5.42%），and GEM groups（9.28%），with statistically significant differences（ P<0.01）. Western blot results showed that，in the HBO + GEM group，the expression levels of apoptosis proteins，such as Bcl-2，significantly decreased，and the expression levels of Bad and Caspase-3 significantly increased，and all the differences were statistically significant（ P<0.01）. In the HBO + GEM group，the expression levels of drug-resistant P-glycoprotein（P-gp）and MRP-related protein（MRP）in the A549/GEM cells significantly decreased，and the differences were statistically significant（ P<0.01）. The expression level of CBX6 in the HBO + GEM group was significantly up-regulated. Conclusion:The combination of HBO and Gem can significantly reduce the resistance of A549/GEM cells to Gem，and its main mechanism is to up-regulate the expression level of channel proteins and down-regulate the expression level of drug-resistant proteins，thus regulating the expressions of apoptosis-related proteins and promoting the apoptosis of A549/GEM cells.