PLGA/O-CMC载药纳米微粒的体外降解及释药行为研究

本研究以聚乳酸-乙醇酸共聚物（PLGA）和自行制备的O-羧甲基壳聚糖（O-CMC）为原料，以5-氟尿嘧啶（5-FU）为抗癌药物模型，采用自身设计的改良复乳法制备了载药纳米微粒。微粒平均粒径为98.5nm，粒径分布指数为0.192，粒子表面∈电位为61．48eV，载药率高达18.9％。然后用SEM动态监测载药纳米粒子降解过程中表面形貌的变化，并连续追踪粒子降解过程中的质量损失和降解介质的pH变化。载药纳米粒子在PBS中的释药行为研究表明，（1）前12h的释药动力学符合Huguchi方程，具有一级释放特性；（2）在20d内的释药动力学符合零级释放特性。细胞凋亡实验结果表明载药纳米粒子对TJ905脑胶质瘤细胞增殖有明显的抑制作用。     

明胶-聚乳酸载药纳米微球的制备及其体外释药研究

采用复合乳液—溶剂挥发法制得明胶—聚乳酸载五氟脲嘧啶(5—Fu)微球，以混合型乳化剂Tween—80：Span—80＝5：1—作为初乳乳化剂，O—羧甲基壳聚糖作为复乳乳化剂，考察了明胶—聚乳酸载药微球的制备条件对微球的成球性、药物包封率及体外释药的影响。结果表明乳化剂的选择、内部水相药物浓度和PLA分子量等均对载药微球的结构与性能产生影响，经优化条件得到了成球性和体外释放都比较好的载药微球。     

靶向抑制晶状体上皮细胞增殖的载药毫微球的研究

采用碳二亚胺法使抗人晶状体上皮细胞单克隆抗体与聚乳酸载 5 -氟尿嘧啶毫微球偶联 ,制备出抗人晶状体免疫毫微球。以牛血清白蛋白作乳化剂采用复乳法制备聚乳酸载 5 -氟尿嘧啶毫微球 ,使毫微球表面吸附牛血清白蛋白 ,再将抗人晶状体上皮细胞单克隆抗体与聚乳酸载 5 -氟尿嘧啶毫微球偶联。采用扫描电镜和透射电镜观察微球形貌和结构 ,用动态光散射粒径分析仪测载药毫微球粒径。ELISA法检测偶联后的抗体活性 ,MTT法检测免疫毫微球对晶状体上皮细胞的抑制作用 ,间接免疫荧光法检测该免疫毫微球与晶状体上皮细胞的特异性结合能力和细胞内化过程。结果显示载药毫微球表面光滑 ,平均粒径为 191.0± 0 .2 0 2nm ,其载药率为 8.2 % ,药物利用率为2 4 .6 %。免疫载药毫微球中的单克隆抗体HILE6保留达到原免疫活性 84 % ,2 4h对兔晶状体上皮细胞抑制率可达6 8.4 2 %。该免疫载药毫微球能与晶状体上皮细胞特异性结合 ,30min后可吸附到晶状体上皮细胞上 ,在 4h内进入细胞质最后进入细胞核。该实验为特异性抑制晶状体上皮细胞增殖 ,预防白内障术后并发症 -后囊混浊提供了重要的科学依据。     

反义表皮生长因子受体RNA对U251胶质瘤细胞生长的抑制作用

目的探讨反义靶向表皮生长因子受体（EGFR）在体内外对U251细胞生长抑制作用。方法构建反义EGFR的pcDNA3表达质粒并进行了脂质体介导的U251人脑恶性胶质瘤细胞系基因转染。应用RT-PCR检测EGFR表达水平，应用MTT法、流式细胞术、Matrigel基质生长实验和Transwell方法评价肿瘤细胞转染前后的生物学行为。进一步应用裸鼠皮下荷瘤模型观察脂质体介导反义EGFR基因治疗对U251细胞生长抑制作用。对肿瘤组织应用免疫组织化学的方法进行EGFR、PCNA和GFAP表达比较。结果脂质体介导反义EGFR可显著抑制U251细胞ECFR表达，MTT法分析显示反义EGFR转染组胞生长抑制率为68％；与对照组和pcDNA3转染组比较，细胞周期分析结果表明p-anti-hEGFR转染组G0～G1期细胞数没有明显变化，进入S期的细胞数较对照组减少了，而进入G2期细胞则增加。Matrigel基质生长实验显示对照组和peDNA3转染组细胞呈正常形态贴壁生长。而p-anti-hEGFR转染组细胞不能贴壁生长，呈团块状簇集生长。Transwell方法显示肿瘤细胞的体外侵袭能力显著下降。裸鼠皮下荷瘤模型实验显示反义EGFR RNA可以显著抑制皮下肿瘤生长，组织病理学分析显示治疗组EGFR表达下降而GFAP表达上调。结论反义EGFR可以显著抑制U251细胞的EGFR表达，在体内外对U251细胞生长均产生明显抑制作用。     

雷帕霉素纳米粒滴眼液联合环孢素A缓释膜治疗兔高危角膜移植术后免疫排斥反应的研究

Objective To evaluate the combined effect of topical rapamycin (RAPA) eye drop in nanometer vector and poly (lactic acid) (PLA) wafers of cyclospoirne A(CsA) in the prevention of acute allograft rejection after rabbit corneal transplantation. Methods It was an experimental study. RAPA was incorporated into the nanometer particles and CsA was incorporated into PLA wafers. A was syngeneic control whose both donor and recipient are New Zealand rabbit. Gray donor corneas were implanted into the 102 recipients of New Zealand albino rabbits with corneal neovascularization who were randomly divided into B, C, D, E, F, G 6 groups to receive the different types of therapy: B was no therapy control; C was eye drop of nanometer vector but no RAPA twice a day,28 days; D was PLA wafers in the anterior chamber of rabbit eyes but no drugs; E was 0.5% RAPA eye drop of nanometer vector twice a day,28 days; F was PLA wafers of CsA in the anterior chamber of rabbit eyes; G was PLA wafers of CsA in the anterior chamber of rabbit eyes and 0.5% RAPA eye drop of nanometer vector eye drop twice a day for 28 days together. Postoperative evaluation included slit-lamp biomicroscopy, histopathology and immunohistoiogy, Cytokines related with neovascularization and immunosuppression in the corneal tissue by RT-PCR. The graft survival was assessed by One-Way ANOVA and q test. Results Corneal allograft survival time: A (100.00±0.00), B ( 8.44±1.24), C (8.89±2.57), D (8.56±2.30), E (43.11±5.58), F (43.67±9.54), G (72.00±15.34)d. Group G led to a statistically significant prolongation of transplant survival and was superior than group E and F which was a statistical prolongation compared with group B, C and D (qGE=11.42, qGF=11.24,qEB=13.64, qEC=13.38, q<=13.46, qFB=13. 82, qFC=13.56, qFD=13.64; P<0.01). Immunohistopathologically, the grafts were subjected to an immune response contained a dense infiltrate of neutorphils,CD4+ and CD8+ T lymphocytes in the group B ,C and D. This cellular infiltrate was a significant reduction in group E,F,G. RT-PCR showed that the gene expression of IL-2 was inhibited earlier (3 days) in group F, G and VEGF gene expression being suppressed later (14 days) in group E, G. Conclusions Combined therapy with topical application of RAPA eye drop of nanometer vector and CsA PLA wafers can significantly prolong the survival of allograft at high-risk. Moreover, topical combined treatment of them is more effective, lower dosage, less side-effects and cheaper than the treatment with topical individual immunosuppressive drug.     

眼用环孢霉素A缓释超微粒的制备及眼内分布研究

目的探讨壳聚糖-胆固醇双亲性聚合物包载环孢霉素A的缓释性及超微粒制备及眼内分布.方法壳聚糖-胆固醇双亲性聚合物与环孢霉素A共溶于溶剂中,对水透析形成超微载药微粒,37℃条件下测试超微粒体外释放状态.以放射性99锝标记壳聚糖超微粒,制成滴眼剂,以SPECT测试超微粒在兔眼中的滞留时间.结果壳聚糖载药超微粒可在6小时内缓释环孢霉素A,超微粒在给药后4小时在眼表具有良好的滞留性.结论以壳聚糖双亲性聚合物包载环孢霉素A对干眼症的治疗具有潜在的应用价值.     

雷帕霉素纳米粒滴眼液联合环孢素A缓释膜治疗兔高危角膜移植术后免疫排斥反应的研究

Objective To evaluate the combined effect of topical rapamycin (RAPA) eye drop in nanometer vector and poly (lactic acid) (PLA) wafers of cyclospoirne A(CsA) in the prevention of acute allograft rejection after rabbit corneal transplantation. Methods It was an experimental study. RAPA was incorporated into the nanometer particles and CsA was incorporated into PLA wafers. A was syngeneic control whose both donor and recipient are New Zealand rabbit. Gray donor corneas were implanted into the 102 recipients of New Zealand albino rabbits with corneal neovascularization who were randomly divided into B, C, D, E, F, G 6 groups to receive the different types of therapy: B was no therapy control; C was eye drop of nanometer vector but no RAPA twice a day,28 days; D was PLA wafers in the anterior chamber of rabbit eyes but no drugs; E was 0.5% RAPA eye drop of nanometer vector twice a day,28 days; F was PLA wafers of CsA in the anterior chamber of rabbit eyes; G was PLA wafers of CsA in the anterior chamber of rabbit eyes and 0.5% RAPA eye drop of nanometer vector eye drop twice a day for 28 days together. Postoperative evaluation included slit-lamp biomicroscopy, histopathology and immunohistoiogy, Cytokines related with neovascularization and immunosuppression in the corneal tissue by RT-PCR. The graft survival was assessed by One-Way ANOVA and q test. Results Corneal allograft survival time: A (100.00±0.00), B ( 8.44±1.24), C (8.89±2.57), D (8.56±2.30), E (43.11±5.58), F (43.67±9.54), G (72.00±15.34)d. Group G led to a statistically significant prolongation of transplant survival and was superior than group E and F which was a statistical prolongation compared with group B, C and D (qGE=11.42, qGF=11.24,qEB=13.64, qEC=13.38, q<=13.46, qFB=13. 82, qFC=13.56, qFD=13.64; P<0.01). Immunohistopathologically, the grafts were subjected to an immune response contained a dense infiltrate of neutorphils,CD4+ and CD8+ T lymphocytes in the group B ,C and D. This cellular infiltrate was a significant reduction in group E,F,G. RT-PCR showed that the gene expression of IL-2 was inhibited earlier (3 days) in group F, G and VEGF gene expression being suppressed later (14 days) in group E, G. Conclusions Combined therapy with topical application of RAPA eye drop of nanometer vector and CsA PLA wafers can significantly prolong the survival of allograft at high-risk. Moreover, topical combined treatment of them is more effective, lower dosage, less side-effects and cheaper than the treatment with topical individual immunosuppressive drug.     

局部重复应用控释BCNU聚乳酸微球治疗U251胶质瘤的实验研究

 目的研究局部重复应用聚乳酸[poly(D,L-lactic acid),PLA]控释卡莫司汀[1,3-bis(2-chlorethyl)-1-nitrosourea,BCNU]微球(BCNU-PLA)对U251人脑胶质瘤的生长抑制作用。方法应用沉淀方法制备包载BCNU的PLA纳米微球。应用扫描电子显微镜观察载药微球形态,分别应用Bratton-Marshall比色法和紫外分光光度法测定微球载药率与药物释放曲线。应用MTT方法检测PBS、BCNU、PLA微球和BCNU-PLA等不同处理方法对U251胶质瘤细胞增殖活性的影响。应用U251裸鼠皮下移植瘤模型为研究对象,连续3次进行PBS、BCNU、PLA微球和BCNU-PLA的治疗,观察实验动物的生存期与皮下肿瘤生长情况。结果扫描电子显微镜观察载药纳米微球呈球形,具有良好的单分散性;BCNU-PLA平均粒径为23.5μm。BCNU-PLA平均载药率为11.5%;以相对分子质量30×10³的PLA制备BCNU-PLA微球的体外药物释放分析显示:BCNU在释放开始的10d表现出较大的突释,释放量达到载药量的40%;随后进入控释期,至4周左右释放了所载药物的50%。与BCNU原药治疗组比较,BCNU-PLA控释微球治疗在体外持续抑制U251胶质瘤细胞的生长;在体内明显抑制裸鼠皮下荷U251胶质瘤的生长,并显著改善荷瘤鼠的全身状况。结论BCNU-PLA载药微球可有效抑制皮下荷U251胶质瘤的生长,是局部化疗治疗胶质瘤的一种新策略。     

一种新型纳米基因载体的制备及体外实验

本实验以聚乳酸和O-羧甲基壳聚糖为基质材料，采用超声波法制备了聚乳酸-O-羧甲基壳聚糖纳米微球，并用环境扫描电镜和XPS对其进行了表征，将聚乳酸-O-羧甲基壳聚糖纳米微球携带寡核苷酸转染TJ905人脑胶质瘤细胞，并通过RT-PCR方法对细胞的转染情况作了一系列的体外检测，结果表明，携带寡核苷酸的聚乳酸-O-羧甲基壳聚糖纳米微球能有效地转染TJ905人脑胶质瘤细胞，同时也能有效地抑制胶质瘤细胞中端粒酶RNA，端粒酶催化亚基RNA的表达和端粒酶的活性，从而抑制人脑胶质瘤细胞生长，达到基因治疗的目的。     

立体定位注射靶向功能载药纳米粒子治疗恶性脑胶质瘤

以转铁蛋白溶液为外水相，纳米沉淀技术制备了表面含转铁蛋白的包载卡莫司汀的聚乳酸纳米微粒，药物释放时间达一周以上。体外细胞实验验证纳米微粒表面转铁蛋白保持了活性，纳米粒子与胶质瘤细胞具有较强的结合能力。立体定位注射纳米微粒至荷瘤鼠瘤腔，SPECT考察载药纳米微粒的体内分布，表明纳米微粒在颅内滞留。与对照组相比，注射载药纳米微粒的大鼠生存期显著延长，核磁共振图象显示其中2只大鼠颅内肿瘤消退，表明载药纳米粒子对恶性胶质瘤具有体内抑制作用。