【摘要】 目的：评估甲氨蝶呤（methotrexate,MTX）修饰的磁性纳米粒子热化疗治疗大鼠乳腺癌的疗效及其对大鼠免疫功能的影响。方法：在雌性Wistar大鼠皮下接种乳腺癌Walker-256细胞建立移植瘤模型，在肿瘤内注射聚乙烯亚胺（polyethyleneimine,PEI）修饰的Fe₃O₄磁性纳米粒子（47T组、42T组和多次42T组）或MTX修饰的Fe₃O₄磁性纳米粒子（47TC组、42TC组和多次42TC组），并在不同温度（47℃和42℃）的磁场作用下进行热疗；以仅注射MTX修饰的磁流体（MFC组）、移植瘤大鼠不做任何处理（空白对照组）、仅在交变磁场中辐照处理30 min（M组）、仅注射PEI修饰的磁流体（MF组）、MTX单药处理（MTX组）以及不接种肿瘤细胞的大鼠（正常组）作为对照组。采用X射线摄片观察磁流体在肿瘤内注射24 h、2周及2个月后，其在肿瘤组织中的分布情况。在治疗24 h后，分别在47T和47TC组中各选取3只大鼠，处死后在电子显微镜下观察磁流体对肿瘤细胞的影响。治疗14 d后，测量除正常组外各组大鼠的肿瘤体积，并进行统计学分析；同时在47TC、47T、42TC、42T、MFC、MTX、空白对照及正常组中各选取4只大鼠，采用ELISA法检测其外周血中IL-2、IFN-γ和IL-4的含量；对剩余大鼠进行长期生存观察。结果：磁性纳米粒子在肿瘤中心区域呈均匀分布，而在肿瘤边缘则分布不均；其主要聚集于肿瘤细胞间隙，并且可以进入肿瘤细胞内。47TC、47T、多次42TC和多次42T组大鼠的肿瘤生长受到抑制（P均<0.05），并且生存率较高。47TC、47T和空白对照组外周血中IL-2和IFN-γ的表达水平升高，而IL-4的表达水平降低（P均<0.05）。结论：47℃30 min及多次42℃60 min热化疗能在一定程度上抑制大鼠乳腺癌的生长，并且延长大鼠生存时间，这可能与47℃30 min热化疗激活了机体的免疫功能有关。更多还原

【Abstract】 Objective: Assessing the therapeutic efficacy of methotrexate（MTX）-modified magnetic nanoparticles in thermo-chemotherapy for rat breast cancer and its impact on immune function.Methods: Female Wistar rats were subcutaneously inoculated with breast cancer Walker-256 cells to establish a transplantation tumor model, and injected with polyethyleneimine（PEI）-modified Fe₃O₄ magnetic nanoparticles（47T group, 42T group and multiple 42T group） or MTX-modified Fe₃O₄ magnetic nanoparticles（47TC group, 42TC group and multiple 42TC group） for thermotherapy under the magnetic field at different temperatures（47 ℃ and 42 ℃）. The rats injected with MTX-modified magnetic fluid only（MFC group） and the tumorbearing rats without any treatment（blank control group）, with irradiation treatment in an alternating magnetic field only for 30 minutes（M group）, with injection of PEI-modified magnetic fluid only（MF group）, with treatment of MTX-mono drug（MTX group） and not inoculated with tumor cells（normal group） were used as control groups. X-ray radiography was used to display the distribution of magnetic fluid in the tumor tissue 24 hours, 2 weeks and 2 months after intra-tumor injection. After 24 hours of treatment, three rats were selected from each of the 47T and 47TC groups, and the effect of magnetic fluid on tumor cells was observed under an electron microscope after execution. After 14 days of treatment, the tumor volume of rats was measured and statistically analyzed. At the same time, 4 rats were selected from each of the 47TC, 47T, 42TC, 42T, MFC, MTX, blank control and normal groups, and the levels of IL-2, IFN-γ and IL-4 in peripheral blood were detected by ELISA method. The remaining rats were observed for long-term survival.Results: The magnetic nanoparticles were evenly distributed in the center of the tumor but unevenly distributed at the tumor’s edge; they primarily localize amomg tumor cells and can penertrate into tumor cells. Tumor growth was inhibited in rats in the 47TC, 47T, multiple 42TC and multiple 42T groups（all P<0.05）, and the survival rates of the rats were high. As compared with the blank control group, the levels of IL-2 and IFN-γ were increased while the IL-4 level was decreased in the 47TC and 47T groups（all P<0.05）.Conclusion: Thermo-chemotherapy at 47 ℃ for 30 minutes and multiple sessions at 42 ℃ for 60 minutes can partially inhibit tumor growth and prolong rat survival. This effect maybe related to the thermo-chemotherapy at 47 ℃ for 30 minutes which can activate the body’s immune function.更多还原