纳米碳吸附5-氟嘧啶提高乳腺癌疗效的基础研究

Efficacy of 5-Fluorouracil-Loaded Carbon Nanoparticles in Breast Cancer

目的观察纳米碳吸附5-氟嘧啶(5-FU)对新西兰白兔乳腺癌淋巴结转移模型的治疗效果。方法将48只雌性新西兰白兔按随机数字表法分为纳米碳组、静脉组及皮下组,各组各16只。所有动物在乳垫下局部注射VX2肿瘤组织悬液建立乳腺癌动物模型,当腋窝触及直径≥5mm肿大淋巴结时进行干预治疗。纳米碳组皮下注射纳米碳-5-FU混悬液、静脉组经兔耳缘静脉注射5-FU、皮下组经皮下注射5-FU,药物剂量均为25 mg·kg-1。治疗15min后各组处死一半动物,治疗5d后处死余下动物。采用超高效液相色谱法检测各组动物血浆、瘤体组织及淋巴结转移灶中的5-FU浓度;常规HE染色切片观察组织中肿瘤细胞坏死程度(ND);脱氧核糖核苷酸末端转移酶介导的dTUP末端标记技术(TUNEL)检测肿瘤细胞凋亡情况。结果治疗15min后,纳米碳组、静脉组及皮下组血浆中5-FU浓度分别为(11.48±2.40)、(30.12±2.94)及(24.98±3.05)μg·mL-1;瘤体中的5-FU浓度分别为(1.17±0.70)、(3.77±0.93)及(4.36±0.91)μg·g-1;淋巴结转移灶中的5-FU浓度分别为(25.70±1.39)、(1.61±0.83)及(2.69±0.74)μg·g-1。纳米碳组淋巴结转移灶中5-FU浓度明显高于静脉组和皮下组,血浆及瘤体中的5-FU浓度明显低于静脉组和皮下组(均P<0.01);静脉组血浆5-FU浓度高于皮下组(P<0.05),瘤体及淋巴结转移灶中5-FU浓度比较差异无统计学意义(P>0.05)。治疗5d后,纳米碳组血浆及淋巴结转移灶中5-FU浓度分别为(0.35±0.13)μg·mL-1、(3.56±0.34)μg·g-1,瘤体中未检测到5-FU;静脉组及皮下组的血浆、瘤体及淋巴结转移灶中均未检测到5-FU。纳米碳组瘤体组织ND、细胞凋亡指数(AI)均明显低于静脉组及皮下组,淋巴结转移灶的ND、细胞AI明显高于静脉组及皮下组(P<0.05或P<0.01)。静脉组与皮下组瘤体组织及淋巴结转移灶中肿瘤细胞的ND、细胞AI比较差异均无统计学意义(均P>0.05)。结论纳米碳能提高肿瘤组织中5-FU的药物浓度,增强药物对淋巴结转移灶的治疗效果。

Objective To observe the therapeutic efficacy of 5-fluorouracil（5-FU）-loaded carbon nanoparticles in a New Zealand white rabbit model of breast cancer with axillary lymph node metastasis.Methods Forty-eight female New Zealand white rabbits were injected locally with VX2 tumor tissue suspension to establish the breast cancer model.When axillary lymph nodes reached≥5mm in diameter,these rabbits with breast cancer were treated with subcutaneous 5-FU-loaded carbon nanoparticle injection（CN group,n=16）,intravenous 5-FU injection（IV group,n=16）,or subcutaneous 5-FU injection（HI group,n=16）at a dose of 25mg·kg-1.Eight rabbits in each group were sacrificed after treatment for 15 minutes and 5days,respectively.The concentrations of 5-FU in plasma,tumor and metastatic lymph nodes were detected by ultra-high performance liquid chromatography.The necrosis degree（ND）of tumor cells was observed by HE staining.The apoptosis index（AI）of tumor cells was determined by TUNEL assay.Results After treatment for 15 minutes,the concentrations of 5-FU in plasma,tumor and metastatic lymph nodes were,respectively,（11.48±2.40）μg·mL^-1,（1.17±0.70）μg·g^-1 and（25.70±1.39）μg·g^-1in CN group,（30.12±2.94）μg·mL^-1,（3.77±0.93）μg·g^-1 and（1.61±0.83）μg·g^-1 in IV group,and（24.98±3.05）μg·mL^-1,（4.36±0.91）μg·g-1 and（2.69±0.74）μg·g^-1 in HI group.Compared with IV group and HI group,the concentrations of 5-FU increased in metastatic lymph nodes but decreased in plasma and tumor in CN group（P0.01）.Compared with HI group,plasma concentrations of 5-FU increased in IV group（P0.05）.No significant differences in the concentrations of 5-FU in tumor and metastatic lymph nodes were found between HI group and IV group（P〉0.05）.After treatment for 5days,the concentrations of 5-FU were,respectively,（0.35±0.13）μg·mL^-1 and（3.56±0.34）μg·g^-1 in plasma and metastatic lymph nodes in CN group.No 5-FU was detected in the tumor in CN group,as well as in the plasma,tumor and metastatic lymph nodes in IV group and HI group.Compared with IV group and HI group,the ND and AI of tumor cells decreased in tumor tissue but increased in metastatic lymph nodes in CN group（P〈0.05 or P〈0.01）.No significant differences in the ND and AI of tumor cells in the tumor and metastatic lymph nodes were found between IV group and HI group（P0.05）.Conclusion Carbon nanoparticles can increase the concentrations of 5-FU in the tumor and improves the efficacy of drug treatment in axillary metastatic lymph nodes.