整合素受体介导的SiRNA和多柔比星靶向耐药肿瘤的研究

 目的 采用整合素受体介导的靶向载体输送系统实现RNA干扰技术和抗肿瘤药物对耐药肿瘤的联合治疗。方法 分别用静电复合法和硫酸铵梯度法制备载多药耐药基因（MDR1）相关的小干扰RNA（siRNA）的精氨酸-甘氨酸-天冬氨酸三肽（RGD）修饰阳离子脂质体复合物和载多柔比星（DOX）的RGD修饰长循环脂质体，采用激光共聚焦显微镜来观察siRNA和多柔比星的细胞摄取和细胞内分布情况；采用流式细胞术和SRB（磺酰罗丹明B）实验测定多柔比星的细胞累积量和多柔比星对人乳腺癌耐药细胞（MCF7/A）的毒性；采用活体成像技术考察了靶向和非靶向制剂输送siRNA到肿瘤模型裸鼠体内的组织分布情况。结果 所制备的各种脂质体的平均粒径均在200 nm以内；与细胞孵育6 h后，观察发现siRNA和多柔比星各自主要分布在细胞质和细胞核中，与非靶向组相比，靶向脂质体组细胞摄取siRNA更快更多，且有利于siRNA在细胞质中均匀分布；细胞毒实验结果证实，1%摩尔比RGD修饰的阳离子脂质体对siRNA的转染效果最好，流式细胞术实验结果也同样证实RGD修饰脂质体组细胞中多柔比星累积量更高；活体成像结果显示荧光标记的siRNA经靶向脂质体输送后主要集中在肿瘤且比非靶向组蓄积量更高。结论 采用RGD修饰脂质体载运技术可将MDR1 siRNA和多柔比星两种药物同位点输送到肿瘤部位提高靶向性，并有利于改善多药耐药肿瘤的治疗效果。     

肺靶向多柔比星微球小鼠体内组织分布特性研究

 目的 考察肺靶向多柔比星微球在小鼠体内的组织分布特性。方法 采用化学交联法制备多柔比星微球,对其特性进行考察,以高效液相色谱法测定多柔比星微球在小鼠体内各组织的药物浓度,并评价其靶向性能。结果 微球外观为橙红色,形态圆整、均匀,5～15 μm的微球占总数的85.5%,载药量为4.05%,小鼠尾静脉分别注射多柔比星原料药溶液和多柔比星微球以后,微球在肺组织的分布明显提高,并且微球在肺组织的相对摄取率、靶向效率比以及峰浓度比分别为多柔比星溶液组的2.21、1.97～3.36以及1.68倍,同时肺组织切片也表明药物微球具有靶向性。结论 多柔比星微球在小鼠体内具有明显的肺部靶向特性,提高治疗效果,同时也降低毒副作用。
     

Angiopep-2修饰载盐酸多柔比星脂质体的制备与评价

 目的 研究用靶向功能基Angiopep-2修饰多柔比星（DOX脂质体,增加药物在脑胶质瘤部位递送。方法 薄膜分散法制备空白脂质体,靶向功能基Angiopep-2通过膜材料中DSPE-PEG-MAL连接对其进行修饰,DOX作为模型药物通过pH梯度法装载,制得Angiopep-2修饰脂质体（Dox-AL。体外实验中,初步考察了大鼠C6细胞对游离DOX、普通DOX脂质体（DOX-NL和DOX-AL的摄取。C6脑胶质瘤模型小鼠尾静脉注射DOX、DOX-NL和DOX-AL,LC-MS/MS检测小鼠血浆、脑和肿瘤组织DOX浓度。结果 DOX脂质体粒径约为100 nm,包封率99%;大鼠C6细胞对DOX-AL的摄取高于DOX-NL;C6脑胶质瘤模型小鼠iv给予剂量为5 mg·kg-1DOX、DOX-NL和DOX-AL后,3组制剂药物在体内快速分布,较缓慢消除,均符合三室模型。与DOX相比,脂质体制剂能显著延长DOX血液循环时间,增加药物入脑机会;DOX-AL在脑和肿瘤中的AUC_0-t分别是DOX-NL的2.92和7.76倍。结论 Angiopep-2修饰的脂质体作为载体可通过受体介导的方式促进药物胶质瘤靶向递送。     

小檗碱增强K562/DOX细胞对多柔比星敏感性的研究

 目的 探讨小檗碱增强耐药K562/DOX细胞对化疗药多柔比星的敏感性的作用。方法 四甲基偶氮唑蓝法检测小檗碱的细胞毒性及其对多柔比星抗肿瘤活性的增强作用;高内涵活细胞成像系统检测无毒剂量小檗碱作用后,多柔比星在K562/DOX细胞内的蓄积量;PI/Hoechst33342双染法检测小檗碱对多柔比星诱导的K562/DOX细胞凋亡的影响;罗丹明123蓄积实验检测小檗碱对P-糖蛋白外排功能的影响。结果 1 μmol·L^-1为小檗碱的无毒剂量,在此无毒剂量下,小檗碱使多柔比星对K562/DOX细胞的IC₅₀降低了1.5倍;1 μmol·L^-1小檗碱可使多柔比星在K562/DOX细胞内的蓄积量增加,增强多柔比星诱导的K562/DOX细胞凋亡, 增加K562/DOX细胞内罗丹明123的蓄积量,从而抑制P-糖蛋白的外排功能。结论 小檗碱可通过抑制K562/DOX细胞膜上P-糖蛋白的外排功能,增加K562/DOX细胞内多柔比星浓度,促进多柔比星对耐药细胞的诱导凋亡作用,逆转K562/DOX细胞的多药耐药性。     

乳糖酸修饰的黄芩苷自组装胶束载药系统的制备及体外评价

目的制备乳糖酸(lactobionic acid,LA)修饰的O-羧甲基壳聚糖(O-carboxymethyl chitosan,OCMC)偶联黄芩苷(baicalein,BC)的自组装胶束,并考察其作为载体共同递送阿霉素(doxorubicin,DOX)和黄芩苷的可行性。方法以OCMC为水溶性骨架,通过酰胺化反应依次将黄芩苷、乳糖酸偶联到骨架上,分别获得O-羧甲基壳聚糖-黄芩苷偶联物(CMBC)和靶向的乳糖酸-O-羧甲基壳聚糖-黄芩苷偶联物(LA-CMBC)。利用核磁、红外确证偶联物的结构;透析-超声法制备自组装胶束并表征;芘荧光探针法测定临界聚集浓度(critical micelle concentration,CMC);制备载药胶束DOX/LACMBC,紫外测定阿霉素的包封率和载药量;透析法考察载药胶束在不同pH值条件下的释放行为;MTT法考察体外抗肿瘤活性。结果为考察取代度对粒径的影响,制备了3种取代度的CMBC胶束,粒径在164～215 nm,LA-CMBC和DOX/LACMBC胶束的粒径分别约为156 nm和180 nm。LA-CMBC胶束的CMC值为(0.081±0.019)mg/mL。载药胶束中阿霉素的包封率为(69.67±3.87)%,载药量为(16.08±0.25)%。体外释放表明DOX/LA-CMBC具有缓释性和pH敏感性。细胞毒性实验表明,DOX/LA-CMBC胶束对HepG2肝癌细胞生长具有显著的抑制作用。结论制备的载药胶束DOX/LA-CMBC粒径均匀、载药量较好,提高了黄芩苷的水溶性,且具有良好的pH敏感性和抗癌活性。     

载紫杉醇的大黄酸偶联物纳米胶束的制备及初步评价

目的制备载紫杉醇的D-α-生育酚聚乙二醇1000琥珀酸酯(D-α-tocopheryl polyethylene glycol 1000 succinate,TPGS)修饰的羧甲基壳聚糖-大黄酸偶联物(PTX/TPGS-CR)纳米胶束,并对其进行初步评价。方法采用透析法,以载药量、包封率及粒径为指标,通过单因素考察优化PTX/TPGS-CR纳米胶束的制备工艺并进行验证。以溶血实验及血管刺激性实验初步考察PTX/TPGS-CR纳米胶束的安全性。四甲基偶氮唑盐微量酶反应比色法(MTT)法考察PTX/TPGS-CR纳米胶束对Hela细胞的毒性。通过激光扫描共聚焦显微镜定性和流式细胞仪定量考察Hela细胞对PTX/TPGS-CR纳米胶束的摄取情况。结果制备工艺优化后制得的PTX/TPGS-CR纳米胶束粒径为(197.3±4.4)nm,PDI为(0.131±0.021),电位为(-31.8±0.5)mV,载药量为(48.20±3.03)%,包封率为(87.26±4.91)%。溶血实验结果表明,其溶血率低于1.71%;血管静脉注射无明显刺激性。其对Hela细胞的杀伤作用具有浓度和时间依赖性,能被Hela细胞高效摄取。结论PTX/TPGS-CR纳米胶束载药量和包封率高,安全性好,其体外抗肿瘤活性稍优于Taxol?。     

N-三甲基壳聚糖包衣多柔比星脂质体的体外血管内皮细胞靶向性研究

 目的 以脐静脉内皮细胞（HUVECs）为模型，考察其对N-三甲基壳聚糖（TMC）包衣的盐酸多柔比星脂质体的摄取情况， 以评价TMC包衣盐酸多柔比星脂质体的体外血管内皮细胞靶向性。方法 采用pH梯度法制备盐酸多柔比星脂质体，以不同取代度的TMC进行包衣，用DAPI定位细胞核，采用激光扫描共聚焦荧光显微镜观察不同TMC包衣盐酸多柔比星脂质体在HUVECs胞浆及胞核的转运及摄取情况。结果 盐酸多柔比星脂质体性质稳定，包封率均在80%以上，粒径在100～200 nm， 随着TMC季铵化程度的增大，TMC包衣盐酸多柔比星脂质体的Zeta电位显著增大(P<0.05)，同时HUVECs对其摄取能力增强，多柔比星能较快释放到胞浆并转运至胞核。结论 TMC包衣盐酸多柔比星脂质体具有较强的体外内皮细胞靶向作用，且与TMC的季铵化程度有关，为进一步研究其体内靶向作用奠定了基础。     

乳糖化-去甲斑蝥素磷脂复合物pH敏感型脂质体肝靶向抗肿瘤活性研究

目的 考察乳糖化-去甲斑蝥素磷脂复合物pH敏感型脂质体(pH-LPC-lips)的体内外抑瘤作用,及其在小鼠体内的肝脏靶向性。方法 以空白脂质体(blank-lips、blank-pH-lips)为对照,MTT法考察乳糖化-去甲斑蝥素(Lac-NCTD)和2种载药脂质体(Lac-lips、pH-LPC-lips)对人体肝癌细胞HepG2的细胞毒作用。采用HPLC法评价HepG2细胞对Lac-NCTD及其脂质体的摄取过程。建立H22肝癌细胞小鼠荷瘤模型考察脂质体在体内抗肿瘤活性。用Cy-7标记羧甲基壳聚糖(CMCT)制备Cy-7荧光标记的pH-LPC-lips,通过小动物活体成像仪,采集荧光信号,考察该脂质体在小鼠体内的靶向性。结果 与Lac-NCTD、Lac-lips相比,pH-LPC-lips在体外对肿瘤细胞HepG2的亲和性更好,细胞毒作用更显著。体内抑瘤实验表明,pH-LPC-lips可以更好地抑制H22肿瘤的生长。pH-LPC-lips可以靶向聚积在小鼠肝脏和肿瘤部位,有很好的靶向作用,从而减小药物毒副作用,提高抗肿瘤效果。结论 优化的pH-LPC-lips可以在呈弱酸性的肿瘤部位主动释药,并对肝脏和肿瘤部位具有靶向性,从而表现出更好的抗肿瘤作用。     

pH/还原敏感型多柔比星前药胶束的制备及体外性能评价

目的 本实验以聚乙二醇 (polyethylene glycol,PEG) 和多柔比星(doxorubicin, DOX)合成的刺激敏感型前药聚合物(PEG-DOX)包载美法仑(melphalan,MEL),制备MEL/PEG-DOX纳米胶束,考察其体外协同抗肿瘤作用。方法 通过希夫碱反应将PEG化的二硫代二丙酸二酰肼(TPH)与DOX结合,形成pH/还原敏感型PEG-DOX前药纳米载体,通过其自组装性能制备MEL/PEG-DOX载药胶束。用透射电镜观察其形态,粒径仪测定其粒径和电位,用超滤法测定载药量和包封率,用透析法评价胶束的药物释放,采用MTT法评价细胞毒性。结果 通过核磁共振氢谱验证了所制备的刺激响应型PEG-DOX前药聚合物;其PEG-DOX载体平均粒径为(188±2.4)nm,多分散系数(PDI)为(0.255±0.008);MEL/PEG-DOX载药胶束的平均粒径为(299.7±2.4)nm,多分散系数(PDI)为(0.301±0.03),Zeta电位为(-0.385±0.02) mV;DOX载药量为(14.85±0.24)%,包封率是(85.78±0.37)%,MEL载药量为(7.36±0.36)%,包封率为(38.79±0.42)%;体外药物释放实验结果表明,MEL/PEG-DOX胶束具有还原敏感和pH敏感性,且还原敏感性大于pH敏感性;细胞毒性实验分析,DOX和MEL在细胞内共同释放,实现了对肿瘤细胞的联合杀伤。结论 MEL/PEG-DOX可以在肿瘤微环境特异性释放,对肿瘤细胞具有协调治疗的作用,具有良好的应用前景。     

载多柔比星杂化介孔二氧化硅纳米粒的制备及其性能研究

 目的 制备载多柔比星的羧基化介孔二氧化硅纳米粒（MSN-COOH-DOX）,考察其体外释放行为和细胞毒性。方法 采用共聚法制备羧基化介孔二氧化硅纳米粒（MSN-COOH）,应用透射电镜表征纳米粒的形态,小角X射线衍射确认介孔结构,氮气等温吸附进行比表面积分析（BET）和孔径,孔容积分析(BJH)。紫外可见分光光度法评价载药量、包封率及体外释放。采用MTT染色法,分析其对MCF-7细胞和Hela细胞的细胞毒性。结果 纳米粒分布均一,平均粒径约80 nm（PDI<0.2）,比表面积为657.9 m2·g-1,孔径为2.27 nm。药物的包封率和载药量分别为54.6％,19.7％。纳米粒经24 h水浴振荡释放达平衡,在pH 5.0释放介质中累积释放分数达到95％。空白纳米粒具有较低的细胞毒性,载药纳米粒对MCF-7细胞和Hela细胞的毒性与游离多柔比星（DOX）相当。结论 共聚法制备杂化介孔二氧化硅纳米粒（MSN-COOH）,具有较高的药物包封率,其可作为抗癌药物DOX的载体,粒子能被摄取,而且能趋于完全释放,载药后可降低DOX的细胞毒性。     

具有线粒体靶向功能的载去甲斑蝥素TPP-PEG-PCL纳米胶束促肝肿瘤细胞凋亡研究

目的制备去甲斑蝥素(3-丙羧基)三苯基溴化膦(TPP)-聚乙二醇-b-聚己内脂(PEG-PCL)纳米胶束,研究其体外释放、细胞内转运及促肝肿瘤细胞凋亡作用。方法采用薄膜水化法制备去甲斑蝥素TPP-PEG-PCL纳米胶束,测定粒径、Zeta电位及显微电镜形态分析,同时对胶束进行稳定性、体外释放、药代动力学和临界胶束浓度测定;以香豆素-6作为荧光探针,评价TPP-PEG-PCL纳米胶束在肝肿瘤细胞内的摄取、溶酶体逃逸及线粒体靶向功能;采用给药剂量等同条件下,评价去甲斑蝥素TPP-PEG-PCL纳米胶束促肝肿瘤细胞凋亡效果。结果去甲斑蝥素TPP-PEG-PCL纳米胶束粒径为(16.8±0.2)nm,Zeta电位为(14.3±0.2)m V,透射电镜图片该纳米胶束呈规则圆球型;荧光试验结果显示,TPP-PEG-PCL纳米胶束可以促进药物的细胞摄取、逃逸溶酶体的捕获,最终靶向聚集在线粒体部位;细胞存活率和Hoechst染色结果显示去甲斑蝥素TPP-PEG-PCL纳米胶束具有很好的促肝肿瘤细胞凋亡作用,去甲斑蝥素TPP-PEG-PCL纳米胶束可以明显降低线粒体膜电位、提高细胞内活性氧(ROS)水平、增加促凋亡蛋白Bcl-2、减少抗凋亡Bax蛋白的表达,这些促凋亡相关的实验结果均明显优于去甲斑蝥素PEG-PCL纳米胶束和去甲斑蝥素,具有统计学意义。结论去甲斑蝥素TPP-PEG-PCL纳米胶束具有良好的肝肿瘤细胞线粒体靶向性和促肿瘤细胞凋亡作用,为一种潜在高效靶向肿瘤细胞线粒体的载药系统。     

�������-ά����E���������ۺ��ｺ�����Ʊ������⿹������������

??OBJECTIVE To enhance the anticancer activity of doxorubicin(DOX) by conjugating DOX and vitamin E succinate (VES) and loading the conjugate into hyaluronic acid-octadecylamine (HA-C₁₈) copolymer micelles.METHODS DOX and VES were conjugated by amide reaction.DOX-VES/HA-C₁₈micelles were prepared via a probe-type ultrasonication technique.The morphology of the micelles was determined using a transmission electron microscopy (TEM).Dynamic light scattering (DLS) technique was used to determine the particle size distribution, hydrodynamic diameters, and stability of the micelles.Ultracentrifugation was exploited for measuring the drug loading (DL) and encapsulation efficiency (EE), and the in vitro release was investigated using a dialysis tubing.The cellular uptake and cellular distribution of drug-loaded micelles in MCF-7 cells were observed by fluorescence microscope, and the fluorescence intensity of DOX was evaluated by flow cytometer.The cytotoxicity of free DOX and drug-loaded micelles was tested by MTT assay against MCF-7 cells.RESULTS DOX-VES/HA-C₁₈ showed a nearly spherical morphology and good stability in PBS (pH 7.4) and 10% FBS.The particle size and zeta potential were (184.6??9.42) nm and (-20.7??1.23) mV, respectively.The DL and EE were (15.8??2.85)% and (94.2??1.32)%, respectively.DOX-VES/HA-C₁₈had a good controlled drug release property.Furthermore,DOX-VES/HA-C₁₈with accumulation in nucleipresented higher anti-tumor activity than free DOX and DOX/HA-C₁₈. CONCLUSION DOX-VES conjugate has synergistic anti-tumor effect and good application prospects.     

�����������������������������ת���ٰ���ҩ��ҩ����������

??OBJECTIVE To prepare a redox and pH dual sensitive nano-carrier based on PAMAM in order to co-loading chemotherapeutics doxorubicin and breast cancer multidrug resistance reversal agent elacridar, and study their in vitro reversal effect. METHODS The infrared spectrum FTIR was used to characterize the carrier. Confocal was used to investigate the intracellular triggered drug release. The reversal effect of breast cancer multidrug resistance and the in vitro anti-tumor activity of doxorubicin and elacridar co-loaded nanoparticles were investigated using flow cytometry and cell toxicity tests, respectively. RESULTS The doxorubicin and elacridar co-loaded nanoparticles (PSSP/DOX/ELC) were successfully prepared, and pH-redox dual sensitive of carrier was proved by cell experiments.And the carrier was uptaken into cells and delivery to lysosome, and drug release was triggered in the lysosome acid condition, then the released drug diffused to the nucleus. The trial of rhodamine 123 accumulation and efflux assay revealed that the accumulation of rhodamine 123 was notably increased after incubation of elacridar in MCF-7/ADR cells. The cytotoxicity of PSSP/DOX/ELC nanoparticles against MCF-7/ADR cell line was significantly stronger than that of either free doxorubicin or only doxorubicin loaded nanoparticles (PSSP/DOX). CONCLUSION The reversal effect of multidrug resistance and the cytotoxicity of cancer cells were significantly enhanced by PSSP/DOX/ELC nanoparticles. PSSP/DOX/ELC nanoparticles is a promising delivery system.     

线粒体靶向的载紫杉醇TPP-PEG-PE纳米胶束的体外评价及促肿瘤细胞凋亡研究

目的制备载紫杉醇TPP-PEG-PE纳米胶束,研究其体外释放行为,考察其线粒体靶向性及促A549肺癌细胞凋亡效果。方法采用薄膜水化法制备载紫杉醇TPP-PEG-PE纳米胶束,以载药量、包封率、粒径为考察因素,优选载紫杉醇TPP-PEG-PE纳米胶束的制备工艺参数,再对优选工艺的纳米载药系统进行表征,采用体外释药、线粒体靶向、肺癌细胞毒性和细胞凋亡实验对该载药系统进行评价。结果载紫杉醇TPP-PEG-PE纳米胶束粒径为(18.7±0.8)nm,Zeta电位为(13.4±0.5)m V,透射电子显微镜结果表明,载紫杉醇TPP-PEG-PE纳米胶束为大小较为均一的规则圆球型。线粒体靶向实验表明TPP-PEG-PE纳米胶束可以促进药物聚集在线粒体部位,肺癌细胞毒性实验显示载紫杉醇TPP-PEG-PE纳米胶束抗细胞凋亡效果良好,Hoechst染色提示凋亡肺癌细胞出现了大量形态学改变,载紫杉醇TPP-PEG-PE纳米胶束可以明显提高促凋亡Caspase-3活性以及减少抗凋亡蛋白Bcl-2和c-IAP1表达量,均显著优于载紫杉醇PEG-PE纳米胶束和紫杉醇组的实验结果(P0.01)。结论载紫杉醇TPP-PEG-PE纳米胶束具有良好的肺癌细胞线粒体靶向性和促肺癌细胞凋亡作用,是一种潜在高效的肺癌细胞线粒体靶向给药系统。     

�������-��ζ�����ع���֬����˷�������ҩ��ҩ���о�

??OBJECTIVE To investigate the synergetic effect of schisandrin B and liposomes on overcoming multidrug resistance(MDR). METHODS Co-delivery of doxorubicin and schisandrin B by liposome(DS-L) were prepared, and doxorubicin solution(F-DOX), schisandrin B and doxorubicin mixture(Sch B+DOX), doxorubicin liposomes(D-L), doxorubicin liposomes and schisandrin B mixture(D-L+Sch B), verapamil and doxorubicin mixture(Ver+DOX) were also prepared as the control. The MTT test were measured, and the amount of doxorubicin in the K562/DOX cells at different time were determined, and time course of uptake and efflux were drawn. RESULTS The MTT test shows that the resistance factor(RF) of group DS-L were 1.68, 14.52 and 1.42 times of group Sch B+DOX, group D-L and group D-L+Sch B respectively. The uptake test shows that amount of doxorubicin of K562/DOX cells in group DS-L was 1.30 and 1.21 times of that in group D-L and group Sch B+DOX respectively. And the efflux test shows DS-L could delay doxorubicin efflux from K562/DOX cells. CONCLUSION The co-delivery of chemotherapeutics and P-gp inhibitors schisandrin B by liposome is a promising approach to overcome MDR. And there is a synergistic effect between liposome and schisandrin B to overcome MDR.     

ľϬ���ػ�Ͻ������Ʊ����俹���������о�

??OBJECTIVE To prepare luteolin-loaded Solutol hs15/Poloxamer188 mixed micelles, evaluate their pharmaceutical property and study their anti-tumor activity. METHODS The luteolin-loaded mixed micelles were prepared by thin-film hydration method. The particle size was measured by laser granulometry, and the morphology was observed under transmission electron microscope (TEM). The in vitro release behavior was determined by the dialysis method. Cell toxicity and uptake assays were employed to evaluate the anti-tumor activity. The targeting effect was studied by fluorescence labeling. RESULTS The prepared luteolin-loaded mixed micelles showed spherical and regular shape with an average particle size of 66.43 nm and its entrapment efficiency was more than 80%. The 12 h-accumulated release ratio in vitro was up to 97.42%. The cytotoxicity of luteolin-loaded mixed micelles on human lung adenocarcinoma cell line A549 was significantly stronger than that of free luteolin and the uptake rate was improved. After injecting DiR-loaded mixed micelles into nude mouse, the drug begun to accumulate in tumors after 2 h and reached the highest concentration at 6 h which was significantly higher than that in other tissues. There remained strong drug distribution in the tumors after 12 h. CONCLUSION The Solutol hs15/ Poloxamer188 mixed micelles have small particle size and high entrapment efficiency and can enhance cell toxicity and uptake with certain passive targeting effect. It is a promising delivery system for anti-tumor drug.     

PLGA-PEG-PLGA温敏水凝胶包载多柔比星脂质体用于治疗小鼠骨肉瘤的研究

目的 制备聚乳酸乙醇酸-聚乙二醇-聚乳酸乙醇酸共聚物(PLGA-PEG-PLGA)水凝胶包载的多柔比星(Doxorubicin,DOX)脂质体的复合载体,并考察其体外性质和抑瘤效果。方法 采用水化薄膜法制备DOX脂质体,考察其粒径分布和包封率,再利用PLGA-PEG-PLGA水凝胶包载制备得到的DOX脂质体得到DOX-Lip-Gel复合载体,考察其体外释放、黏性测试以及对荷瘤小鼠的治疗效果。结果 制备得到的DOX-Lip的粒径约为(89.3±4.7) nm,包封率约为(85.3±2.6)%,PLGA-PEG-PLGA水凝胶在25 ℃处于溶液状态,而在37 ℃时可凝固成胶,黏性测试结果表明水凝胶的相变温度约为30 ℃。并且水凝胶聚合物具有良好的生物相容性,在体内可以缓慢的降解。与对照组相比,DOX-Lip-Gel可以缓慢的释放药物,且释放期长达200 h。体内抑瘤实验表明DOX-Lip-Gel具有更好的抗肿瘤效果。结论 制备得到的DOX-Lip-Gel对荷瘤小鼠进行瘤周给药,对抑制骨肉瘤在小鼠体内的增长具有显著的抑制作用。     

�������-TiO2�������˷�������ҩ��ҩ���о�

??OBJECTIVE To investigate the effect of TiO₂ nanoparticles on overcoming cancer multidrug resistance(MDR). METHODS Doxorubicin-TiO₂ nanoparticles(DTN) were prepared, the K562/DOX cells were chosen as the model cells. And doxorubicin solution(F-DOX) and doxorubicin liposomes(DOX-L) were also prepared as the control. The MTT assay were measured, and the amount of doxorubicin in the K562/DOX cells at different time were determined by HPLC. The P-gp expression were detected by flow cytometry.RESULTS The MTT assay shows that IC₅₀ of group DTN were lower than that of group F-DOX. The uptake test shows that amount of doxorubicin in K562/DOX cells of group DTN was 1.23 times of group DOX-L when in 4 h, and the efflux test shows that amount of doxorubicin in K562/DOX cells was 1.18 times of group DOX-L. The flow cytometry result revealed that the effect of TiO₂ nanoparticles on overcoming MDR maybe through down-regulating the expression of P-gp in K562/DOX cells.CONCLUSION The TiO₂ nanoparticles are a new inorganic materials-based nanoparticles which promising approach to overcome MDR.     

Protective effect of Spirulina against doxorubicin-induced cardiotoxicity

The generation of reactive oxygen species and mitochondrial dysfunction has been implicated in doxorubicin (DOX)-induced cardiotoxicity. The aim of the present study was to determine whether Spirulina, a blue-green algae, could serve as a cardioprotective agent during DOX treatment in a mouse model. Mice were treated with DOX (4 mg/kg bw, intraperitoneally), weekly, for 4 weeks. Spirulina was administered orally for 3 days twice daily, then for 7 weeks along with the four equal injections of DOX. Cardiotoxicity was assessed, at 3 weeks after the end of the DOX-treatment period, by mortality, volume of ascites, liver congestion, oxidative stress and ultrastructural changes of heart tissue. The DOX-treated animals showed higher mortality (53%) and more ascites. Myocardial damage, as assessed by ultrastructural changes, showed loss of myofibrils, cytoplasmic vacuolization and mitochondrial swelling. Myocardial superoxide dismutase and glutathione peroxidase activities were decreased and lipid peroxidation was increased. Pretreatment with Spirulina significantly protected the mice from DOX-induced cardiotoxic effects as evidenced from lower mortality (26%), less ascites, lower levels of lipid peroxidation, normalization of antioxidant enzymes and ultrastructural studies showing minimal damage to the heart. In vitro cytotoxic studies using ovarian cancer cells demonstrated that Spirulina did not compromise the anti-tumor activity of doxorubicin. These results suggest that Spirulina has a protective effect against cardiotoxicity induced by DOX and it may, therefore, improve the therapeutic index of DOX.