长春新碱靶向缓释微球治疗鼠腺样囊性癌的研究

VCR.loaded nanoparticles as targeted delivery system for the treatment of orbital adenoid cystic carcinoma

目的制备连接有叶酸（FA）的长春新碱（VCR）纳米微球（NP），简称为FA-PLGA（VCR）．NP，观察其对体外培养的腺样囊性癌（ACC-2）细胞及裸鼠眼眶移植瘤的抑制作用。方法实验研究。采用改良的复乳法制备FA-PLGA（VCR）-NP；四甲基偶氮唑盐比色法比较细胞生长抑制率，设VCR、长春新碱微球PLGA（VCR）-NP及FA—PLGA（VCR）-NP组，药物浓度分为0．05、0．25、0．50、1．00、5．oo、10．00、30．00mg／L，检测加药后第1、2．3、4、5天吸光度值；瘤细胞悬液接种法建立裸鼠腺样囊性癌眼眶移植瘤动物模型，分VCR、PLGA（VCR）-NP、FA-PLGA（VCR）-NP及对照组，观察给药后第1、7、14天，各组肿瘤体积抑制率、高效液相色谱法测定肿瘤内残余药物浓度，以及不同时间组织电镜和组织病理学观察。不同时间正常对照与空白微球A值比较采用t检验。考虑到药物、浓度、时间以及三者之间的交互作用，采用多因素方差分析法对比药物对ACC-2细胞增殖的影响。体积抑制率及药物残余浓度比较均采用单因素方差分析，多重比较采用LSD法。结果FA-PLGA（VCR）-NP呈规则球形，平均粒径249．2nm，载药率4．53％，体外释放时间达14d；PLGA—NP与ACC-2细胞共培养5d，细胞存活率达80％以上（t=1．952—3．285，P=0．081—0．190）；FA-PLGA（VCR）-NP对ACC-2细胞的抑制率显著高于VCR，并呈时间和浓度依赖性（F=4．798～563．479，P=0．000—0．006）；靶向微球附着于肿瘤细胞表面，这种识别可以被FA竞争性抑制；PLGA（VCR）-NP组和FA—PLGA（VCR）-NP组对裸鼠移植瘤的体积抑制率显著高于VCR组（P=0．029，0．016）；FA-PLGA（VCR）．NP组高于PLGA（VCR）-NP组，但差异无统计学意义（P=0．376）；给药后第1、7、14天肿瘤残留药物浓度存在差异，时间对浓度的影响具有统计学意义（P=0．000）；透射电镜观察14d肿瘤细胞内仍有高电子密度的纳米颗粒聚集，肿瘤细胞坏死明显，注射周围组织结构形态正常。结论VCR靶向缓释微球具有稳定的载药率和体外释放行为，具有良好的靶向识别力，体外及体内实验证实具有优于原药的抗肿瘤能力。

Objective To prepare and observe the properties of Folate Receptor-mediated VCR- loaded nanoparticles, which is abbreviated as FA-PLGA （VCR）-NP and to study the inhibitory effect of FA- PLGA （ VCR）-NP in ACC-2 cells in vitro and in ACC in BALB/c-nu mice. Methods The mAified W/O/W extraction-evaporation technique was chosen to prepare FA-PLGA （VCR） -NP. Tumor cells were divided into three groups： VCR, PLGA（VCR）-NP and FA-PLGA（VCR）-NP. Seven doses （0. 05, 0. 25, 0. 50, 1.00, 5.00, 10. 00,and 30. 00 rag/L） of VCR were tested in the cell culture mAel. After 1, 2, 3, 4 and 5 days, the cell growth inhibition ratio was evaluated by MTT colorimetry. Nude mice mAel of orbital ACC was built by injecting ACC cell suspension and divided into four groups： VCR, PLGA （VCR）-NP, FA-PLGA（ VCR）- NP, and control group. After 1 day, 7 days and 14 days, the inhibition ratio of gross tumor volume was observed. Residual concentrations of VCR in tumors were evaluated by HPLC. The feature of histopathology was observed by electron microscopy. The effect of empty nanoparticles on ACC-2 cells was compared with normal control group using t-test to analyze. On account of different drugs, concentration, time and the interaction of them, multivariate analysis of variance was used to analyze their relationship. Inhibition rate and residual volume of drug concentrations were compared using one-factor analysis of variance and LSD method. Results FA-PLGA （VCR）-NP were smooth and spherical with a mean particle size of 249. 2 nm. The drug loading efficiency was 4.53%. The release of VCR from PLGA nanoparticles can persist for 14 d. After blank particles PLGA-NP and ACC-2 cells were co-cultured for 5 days, call viability had remained at more than 80 percent（t = 1. 952 - 3. 285, P = 0. 081 - 0. 190）. The inhibitory effect of FA-PLGA （VCR） - NP was more effective than VCR alone after a period of time （ F = 4. 798 - 563.479, P = 0. 000 - 0. 006 ）. The effects of the treatment were both in dose-dependent and time-dependent manner. Targeting particles could attach to tumor surface, via folate receptor. FA was competitive inhibitor of this recognization. The volume inhibition ratios of FA-PLGA （VCR）- NP and PLGA （VCR）-NP were significant higher than VCR （P=0. 016, P = 0. 029）. The inhibition ratio of FA-PLGA（VCR）-NP was higher than that of PLGA （VCR）-NP, but there was no statistical difference（P =0. 376）. There was significant different between residual concentrations of VCR on the U^st, 7^th and 14^th days. TEM pictures showed a mass of electron-dense microspheres in tumor cells on the 14^th day. Tumor necrosis was obvious, while surrounding tissues were normal. Conclusions FA-PLGA（VCR）-NP are stable and have high drug entrapment efficiency and high effect of growth inhibition in vitro. It can be proposed as a potentially controlled and targeted delivery system for the treatment of ACC.