半导体激光诱导耐药MG-63细胞凋亡的机制

目的：初步探讨半导体激光诱导耐药MG-63细胞凋亡的分子机制，为其临床应用提供理论依据。方法：MG-63耐药细胞（密度为1.0×10⁹•L^-1）经激光照射分为对照组及半导体激光30、60、90和120　J•cm^-2组。MTT法检测耐药MG-63细胞活性；流式细胞仪检测细胞活性氧含量；Western blotting方法检测caspase-8、caspase-9和caspase-3蛋白表达。结果：与对照组比较，半导体激光60、90和120 J•cm^-2组MG-63耐药细胞活性降低(P<0.05或P<0.01)，细胞增殖抑制率随激光剂量增加而升高；与对照组比较，以上各半导体激光组激光照射后细胞内活性氧水平升高(P<0.05或P<0.01)，同时细胞中caspase-9和caspase-3蛋白的表达量随激光剂量增加而增强(P<0.05或P<0.01)，而caspase-8蛋白的表达量差异无显著性（P>0.05）。半导体激光30 J•cm^-2组细胞活性、活性氧含量、caspase-9和caspase-3蛋白的表达与对照组比较差异均无显著性（P>0.05）。结论：60～120 J•cm^-2组的半导体激光可通过线粒体凋亡通路诱导耐药MG-63细胞凋亡，从而抑制细胞增殖，这一过程与活性氧的产生密切相关。

Apoptosis of multi-drug resistance cell lines(MDR-MG-63) induced by semiconductor laser

Objective To find the molecular mechanism of apoptosis of multi-drug resistance cells lines(MDR-MG-63) induced by semiconductor laser and provide theoretical basis for its clinical application. Methods MDR-MG-63 cells were divided into five groups:control group and semiconductor laser groups(30,60,90,120J·cm-2).The cell viability was detected by MTT assay; reactive oxygen species (ROS) was detected by flow cytometry;the protein expressions of caspase-8,caspase-9 and caspase-3 were assayed by Western blotting.Results Compared with control group,the cell viabilities decreased gradually with the increasing of dose in semiconductor laser groups (60,90,120J·cm-2)(P<0.05 or P<0.01),a lot of ROS were found (P<0.05) after multi-drug resistance MG-63 cells lines were irradiated,at the same time the expression levels of caspase-9 protein and caspase-3 protein were increased(P<0.05 or P<0.01) in a dose-dependent manner,but the level of caspase-8 protein didn't obviously change (P>0.05);the differences of the cell viability,ROS,the expression levels of caspase-9 protein and caspase-3 protein between semiconductor laser(30J·cm-2)group and control group were not significant (P>0.05).Conclusion Semiconductor laser can induce apoptosis of MG-63 cells by mitochondrion pathway,and the process may be associated with the increasing of ROS.