亚甲蓝光动力疗法联合阿霉素治疗乳腺癌的实验研究

Basic experimental research on methylene blue-mediated photodynamic therapy combined with adriamycin for breast carcinoma

目的:探讨亚甲蓝介导的光动力疗法联合阿霉素对小鼠乳腺癌细胞系4T1的体外及体内抑瘤效应及其相关机制,为临床应用提供理论依据。方法:本研究分为空白对照组、阿霉素组、光动力治疗组及联合治疗组。MTT法检测光动力疗法联合阿霉素对乳腺癌细胞增殖的影响。流式细胞术检测细胞凋亡及坏死情况。Rhodamine123检测线粒体膜电位变化。建立乳腺癌荷瘤小鼠模型,绘制肿瘤生长曲线,观察治疗效果。结果:体外实验表明光动力疗效与光敏剂呈剂量依赖性,而联合阿霉素可以增强抑瘤效应。阿霉素组细胞死亡率较低,光动力治疗组以早期及晚期凋亡为主,联合治疗组以晚期凋亡及坏死为主。与空白对照组比较,光动力治疗组及联合治疗组线粒体膜电位显著降低,差异均有统计学意义(P<0.05),联合治疗组较光动力治疗组线粒体膜电位更低(P<0.05)。体内实验显示光动力疗法可以显著抑制小鼠乳腺癌皮下移植瘤生长,而联合阿霉素可以增强抑瘤作用。结论:亚甲蓝介导的光动力疗法对乳腺癌细胞及移植瘤的生长抑制作用明显,联合阿霉素可增强抑瘤效果。光动力疗法以细胞凋亡为主,其机制可能与降低肿瘤细胞线粒体膜电位相关。

Objective： This work aimed to investigate the therapeutic efficacy of methylene blue （MB）-mediated photodynamic therapy （PDT） with adriamycin （ADM） on 4T1 mouse mammary carcinoma cells in vitro and in vitro, thereby providing a theoretical basis for clinical applications. Methods： The experimental study was divided into four groups, namely, control （Group One）, ADM （Group Two）, PDT （Group Three）, and therapeutic alliance or PDT＋ADM （Group Four）. Methyl thiazolyl tetrazolium assay was employed to determine the effects of the combined therapy on the proliferation of breast cancer cells. Cell apoptosis and necrosis were measured by flow cytometry with Annexin V-FITC/PI double staining. Rhodamine 123 was used to test the change in the mitochondrial membrane potential （MMP） of the 4T 1 cells. A 4T 1-bearing BALB/c mice model was established, and the tumor volume was measured to draw the growth curve. Results： In Groups Three and Four, cell survival rate gradually decreased as the concentration of the photo- sensitizer increased. A low death rate was exhibited by Group Two, whereas early and late apoptosis were observed in Group Three and late apoptosis and necrosis were found in Group Four. The results of the MMP detection showed that Groups One, Three, and Four had significant changes （P〈0.05）, with the highest MMP decrease in Group Four （P〈0.05）. The in vivo experiments demonstrated that PDT significantly inhibited the growth of 4T 1-xenografted tumor and that the inhibitory action can be further enhanced with ADM. Conclusions： MB-mediated PDT, which is strengthened by the combination of PDT and ADM, has a significant lethal effect on 4T1 cells in vitro and in vitro. The lethal effect of PDT on cancer cells is shown in the apoptosis and can be attributed to the decrease in MMP.