复合bFGF缓释微球的制备及其对成纤维细胞增殖作用的实验研究

制备复合碱性成纤维细胞生长因子 (bFGF)可降解缓释微球 ,考察其生物活性的保存情况 ,以及它对成纤维细胞的作用。采用改良的乳化冷凝法交联制备复合bFGF的明胶缓释微球 ,将它加入成纤维细胞的培养液中 ,用细胞计数法、四甲基偶氮唑盐微量反应比色法 (MTT法 )测定细胞增殖情况。结果表明 ,复合bFGF的缓释微球平均粒径 12 .36± 3.5 6 μm ;培养 1d后各组细胞计数、吸光度 (A)值差异均无显著性 ;5d后 ,缓释微球组细胞计数、吸光度 (A)值明显高于对照组 ;7d后 ,缓释微球组值仍高于其它组 ,但差异无显著性。复合bFGF的缓释微球制备工艺简便 ,成球性好 ;能较长时间地持续释放活性bFGF ,明显促进成纤维细胞的增殖。     

骨形态发生蛋白2/聚乳酸缓释微球的制备及表征

背景:聚乳酸具有良好的生物相容性,是优良的药物缓释载体。目的:制备重组人骨形态发生蛋白2/聚乳酸缓释微球,考察其理化特性。方法:采用复乳溶剂挥发法制备重组人骨形态发生蛋白2/聚乳酸缓释微球,进行扫描电镜、激光粒度、Zeta电位、溶胀性能检测及采用ELISA试剂盒检测包封率、载药率及体外释药率。结果与结论:扫描电镜见重组人骨形态发生蛋白2/聚乳酸缓释微球微球近似圆形,形态较规则,分散性较好,表面光滑。激光粒度分析重组人骨形态发生蛋白2/聚乳酸缓释微球微平均粒径839.6 nm,Zeta电位(-32.93±3.74)mV,微球溶胀系数1.157±0.059,包封率及载药率分别为(88.943±2.878)%,(0.026±0.001)%;微球在第1天释药约10.199%,随后释药较恒定,至第19天累计释药率为54.643%。说明制备出的重组人骨形态发生蛋白2/聚乳酸缓释微球的粒径达到中华人民共和国药典第10版二部关于亚微球的定义标准及包封率不低于80%的要求,并且在体外具有很好的缓释功能。     

bFGF纳米控释载体对骨髓间充质干细胞的生物学作用

本研究旨在探讨甲基丙烯酸缩水甘油酯右旋糖酐(dex-GMA)载碱性成纤维细胞生长因子(bFGF)凝胶纳米微球(dex-GMA-bFGF-NPs)对骨髓间充质干细胞(BMSCs)生物学作用。采用改良乳液聚合技术合成纳米微球,将单纯bFGF(A组)、空白dex-GMA凝胶纳米微球(B组)和载bFGF凝胶纳米微球(C组)加入骨髓间充质干细胞培养液中,不添加任何添加物的单纯MSCs为空白对照组(D),用细胞计数法、噻唑蓝比色法(MTT法)、流式细胞术观察细胞增殖情况;并检测细胞ALP活性,以反映dex-GMA-bFGF-NPs对BMSCs分化情况的影响。结果显示:dex-GMA-bFGF-NPs大小均匀,包封率高达88%,85%的bFGF在前14 d释放。dex-GMA-bFGF-NPs对bFGF缓释有效促进BMSCs的增殖,在培养12 d后,A、B、C和D组细胞数分别为(21.97±0.25)×104个细胞/ml(、12.43±0.13)×104个细胞/ml(、27.45±0.78)×104个细胞/ml和(12.03±0.43)×104个细胞/ml,差异有统计学意义(P0.05),培养3 d后,A组的G2/M+S期百分数最高,7 d后,C组的G2/M+S期百分数最高。结论:dex-GMA-bFGF-NPs可控制活性bFGF的长时间持续释放,作为bFGF的缓释载体,可明显促进骨髓间充质干细胞的增殖和分化。     

聚羟基丁酸-羟基辛酸共聚酯载生长因子的缓释纳米微球

背景:骨形态发生蛋白2可增加软骨细胞和祖细胞基质的产生,可增强组织金属蛋白酶抑制因子1、sox9基因、Ⅱ型胶原以及聚集蛋白聚糖的表达,具有诱导间充质细胞迁徙、增殖、分化,最终促使软骨、骨形成的作用。目的:制备重组人骨形态发生蛋白2聚羟基丁酸-羟基辛酸共聚酯纳米微球系统纳米微球缓释系统,观察微球生长因子形态和粒径分布、载药量、包封率、体外缓释时间及生物活性。方法:采用复乳-干燥法制备重组人骨形成蛋白2聚羟基丁酸-羟基辛酸共聚酯纳米微球系统,体外分离培养猪软骨细胞。实验分为3组:第1组培养液不添加药物做为对照;第2组培养液中添加含20μg/L重组人骨形态发生蛋白2;第3组培养液中添加20μg/L重组人骨形态发生蛋白2聚羟基丁酸-羟基辛酸共聚酯纳米微球系统纳米微球;其中在第2组和第3组又将重组人骨形态发生蛋白2和重组人骨形态发生蛋白2聚羟基丁酸-羟基辛酸共聚酯纳米微球系统纳米微球分别设为55,100μg/L两种的有效浓度,采用MTT法检测微球对软骨细胞增殖的影响,模拟体内条件观察纳米微球的体外缓释性及生物活性。结果与结论:该纳米微球表面光滑圆整,球体大小均匀,粒径为231-415 nm,扫描电镜平均粒径323 nm。微球的包封率和载药量分别为(79.63±0.16)%和(1.92±0.16)%。根据15 d内对重组人骨形态发生蛋白2聚羟基丁酸-羟基辛酸共聚酯纳米微球的体外释药的观察,保持持续释放重组人骨形态发生蛋白2,且释放的浓度呈增长水平。该微球缓释系统有生物活性,能显著促进猪软骨细胞的增殖,其效应高于单纯重组人骨形态发生蛋白2的效应。提示重组人骨形态发生蛋白2聚羟基丁酸-羟基辛酸共聚酯纳米微球缓释系统包封率、载药量、体外释药性以及生物活性符合纳米微球的一般规律,能够满足相应的软骨缺损修复要求。     

制备复合生长因子的缓释微球并考察其对细胞的影响

目的:制备复合碱性成纤维细胞生长因子的可降解缓释微球,考察其生物活性保存情况,以及其对上皮细胞的作用.方法:采用改良的乳化冷凝法交联制备明胶缓释微球,将其加入上皮细胞的培养液中,用细胞计数法、四甲基偶氮唑盐微量反应比色法(MTT法)测定细胞增殖情况.结果:缓释微球平均粒径(12.36±3.56)μm;培养1 d后各组细胞计数、吸光度(A)值差异均无显著性意义;5 d后,缓释微球组细胞计数、吸光度(A)值明显高于对照组;7 d后,缓释微球组值仍高于其它组,但差异无显著性意义.结论:复合生长因子的缓释微球制备工艺简便,成球性好;能较长时间持续释放活性生长因子,明显促进细胞增殖.     

利福平/聚乳酸-聚羟基乙酸缓释微球的制备及特性

背景：虽然国内外有很多制备利福平/聚乳酸-聚羟基乙酸共聚物(poly lactic acid-glycolic acid copolymer,PLGA)微球的报道,但这些微球粒径多在10 μm左右,不适合与磷酸钙骨水泥复合制备成具有良好降解性的抗结核修复材料。 目的：制备大粒径利福平/PLGA缓释微球,观察其理化特性和体外缓释特性。 方法：以PLGA为载体,将利福平分散于PLGA的有机溶剂中,采用复乳溶剂挥发法制备利福平/ PLGA缓释微球。光镜和扫描电镜下观察微球的形态特征,测定微球平均直径和跨距,高效液相色谱法测定载药量和包封率,以溶出法和高效液相色谱法观察其体外释药特性,并拟合药物体外释放曲线建立曲线方程。 结果与结论：利福平/PLGA微球电镜观察呈圆球形,分散性好,粘连少,粒径分布集中,平均粒径(80.0±9.4) μm。载药量、包封率分别为(33.18±1.36)%,(54.79±1.13)%。体外缓释试验显示突释期内微球释放度为(14.66±0.18)%,前3 d累计释放度(18.09±0.45)%,到42 d体外累积释放度达到(92.17±1.23)%。提示利福平/PLGA微球具有良好的缓释效果,是一种较为理想的抗结核药物的载体材料和释放系统;PLGA是良好的药物缓释载体,可以用来制备载药缓释微球。     

全反式维甲酸-聚酸酐长效缓释剂研制及其可行性

背景：如何提高全反式维甲酸疗效、稳定性和降低毒副作用是临床治疗所面临的最大问题。近年来用可生物降解的聚合物为材料,通过乳化包囊等分散技术将药物制备成微粒分散体系,用作缓释、控释注射剂的研究日益增多。 目的：研制全反式维甲酸-聚酸酐长效缓释微球肿瘤治疗剂,观察其体内外全反式维甲酸经时缓释变化规律。 方法：采用乳剂-扩散溶剂挥发法制备全反式维甲酸-聚酸酐长效缓释微球肿瘤治疗剂,扫描电镜检测微球外观及微球粒径,高效液相色谱法检测微球载药量、包封率及体内外释药量。 结果与结论：所制微球治疗剂光滑圆整,大小均一,平均粒径(154.42±26.76) nm,载药率(16.5±1.45)%,包封率(87.84±4.79)%;体外释放实验证明该微球治疗剂可持续释放全反式维甲酸约50 d,将其肌肉注射到大耳白兔体内,可稳定缓释全反式维甲酸近45 d。结果表明该微球治疗剂载药量及包封率均较高,体内外释药平稳并且具有明显的长效缓释作用。     

盐酸万古霉素@聚乳酸-羟基乙酸共聚物-壳聚糖-透明质酸复合缓释微球的制备及体外评价北大核心

背景:局部抗生素缓释系统可解决全身应用抗生素时引发的全毒性反应与短期局部注射抗生素半衰期短的问题。目的:制备盐酸万古霉素@聚乳酸-羟基乙酸共聚物-壳聚糖-透明质酸[vaneomyeinhydroehlorid@poly(lactic acid glycolic acid)-chitosanhyaluronic acid,VA@PLGA-CS-HA]复合缓释微球,并对其性能进行评价。方法:采用乳液法制备VA@PLGA-CS-HA复合缓释微球与未载药PLGA-CS-HA复合微球,其中载药微球中万古霉素的质量浓度分别为25,50,100 g/L,检测载药微球的载药量、包封率与体外缓释性能。将3种载药微球分别与金黄色葡萄球菌菌液共培养,相应时间点内检测抑菌率。将4种微球浸提液分别与MC3T3-E1细胞和MG-63细胞共培养,培养1,3,7 d后采用CCK-8法检测细胞毒性。结果与结论:(1)含盐酸万古霉素25,50,100 g/L载药微球的包封率分别为(79.70±5.11)%,(86.41±3.91)%,(63.18±1.96)%,载药量分别为(3.98±0.26)%,(8.64±0.39)%,(12.63±0.39)%;50 g/L载药微球的包封率高于100 g/L载药微球(P<0.05),100 g/L载药微球的载药量高于其他两组(P <0.05);(2)3种载药微球在24 h内均无明显的突释,其中50 g/L载药微球不同时间点的药物释放率快于其他两组,100 g/L载药微球不同时间点的药物释放量高于其他两组,并且3组在56 d时释放的药物质量浓度均高于盐酸万古霉素最小抗菌浓度;(3)3种载药微球均能在一定时间内有效杀死金黄色葡萄球菌,在第14-28天期间3种微球的相对菌落率低于3%,说明3种载药微球能持续而有效杀灭金黄色葡萄球菌;(4)含盐酸万古霉素25,50 g/L载药微球对MC3T3-E1细胞和MG-63细胞无明显的细胞毒性,100 g/L载药微球具有一定的细胞毒性;(5)结果表明,VA@PLGA-CS-HA微球具有良好的缓释性能、抗菌能力与生物组织相容性。     

制备壳聚糖微球体外缓释TGF-β_1的研究

应用离子交联沉淀法制备壳聚糖-转化生长因子（TGF-β1）缓释微球,研究其体外缓释性能。采用离子交联沉淀法制备壳聚糖微球,以其包裹TGF-β1,制备具有缓释效能的壳聚糖-TGF-β1缓释微球。用扫描电镜、激光粒度分析仪、Elisa法等观察其表面形态,测定药物载药率、包封率、体外缓释效率等指标。结果表明：所得微球球形良好,表面光滑,粒径分布集中,平均粒径272nm。壳聚糖微球有较高的药物包封率,达80.60%。体外释放试验提示,TGF-β1初期存在突释现象,前24h释放达27%,但其后可从壳聚糖微球中稳定释放,7d累计释放达41%。离子交联沉淀法制备壳聚糖缓释微球方法简单易行,所得壳聚糖-TGF-β1微球具有良好的缓释效能,提示其在组织工程领域具有良好的应用前景。     

制备壳聚糖微球体外缓释TGF-β1的研究

应用离子交联沉淀法制备壳聚糖-转化生长因子（TGF-β1）缓释微球,研究其体外缓释性能。采用离子交联沉淀法制备壳聚糖微球,以其包裹TGF-β1,制备具有缓释效能的壳聚糖-TGF-β1缓释微球。用扫描电镜、激光粒度分析仪、Elisa法等观察其表面形态,测定药物载药率、包封率、体外缓释效率等指标。结果表明：所得微球球形良好,表面光滑,粒径分布集中,平均粒径272nm。壳聚糖微球有较高的药物包封率,达80.60%。体外释放试验提示,TGF-β1初期存在突释现象,前24h释放达27%,但其后可从壳聚糖微球中稳定释放,7d累计释放达41%。离子交联沉淀法制备壳聚糖缓释微球方法简单易行,所得壳聚糖-TGF-β1微球具有良好的缓释效能,提示其在组织工程领域具有良好的应用前景。     

碱性成纤维细胞生长因子共聚物缓释微球与兔跨区轴型皮瓣的成活

背景：研究表明使用生长因子直接或间接刺激新生血管形成可以促进皮瓣远端缺血部分的成活。 目的：观察碱性成纤维细胞生长因子-聚乳酸-聚羟基乙酸共聚物缓释微球对家兔侧腹制作跨区轴型皮瓣成活的影响。 方法：取24只健康家兔制作侧腹壁跨区轴型皮瓣,随机分组：实验组术前5 d皮内注入碱性成纤维细胞生长因子-聚乳酸-聚羟基乙酸共聚物微球,对照组术前5 d皮内注入碱性成纤维细胞生长因子+空微球悬浊液,空白对照组术前5 d皮内注入生理盐水。5 d后掀起皮瓣原位缝合。 结果与结论：①皮瓣成活率：实验组显著高于对照组和空白对照组(P < 0.01),②皮瓣组织学变化：实验组新生血管增生明显,以毛细血管为主。③CD34+免疫组织化学结果：实验组新生血管大量形成,平均血管数目高于对照组和空白对照组(P < 0.05)。表明术前5 d局部注射碱性成纤维细胞生长因子-聚乳酸-聚羟基乙酸共聚物缓释球可促进皮瓣新生血管形成,增加皮瓣血运,促进皮瓣成活。     

许旺细胞及小肠黏膜下层复合生长因子缓释微球修复周围神经缺损

背景：前期实验已初步证实许旺细胞复合小肠黏膜下层及碱性成纤维细胞生长因子构建的人工神经具有体外神经活性、趋化性。 目的：观察许旺细胞及小肠黏膜下层复合碱性成纤维细胞生长因子缓释微球修复周围神经缺损后神经传导的再通情况。 方法：制作SD大鼠坐骨神经缺损模型,随机分组：实验组以许旺细胞及小肠黏膜下层复合碱性成纤维细胞生长因子缓释微球修复,阳性对照组以许旺细胞及小肠黏膜下层复合游离碱性成纤维细胞生长因子修复,阴性对照组以许旺细胞及小肠黏膜下层修复,空白对照组以自体神经修复。 结果与结论：术后16周实验组再生神经纤维数目,DiI示踪标记的阳性神经元数量、S-100及神经细丝蛋白的阳性表达率、髓鞘及再生轴突的超微结构恢复、神经传导速度及复合动作电位的改善均优于阳性对照组与阴性对照组(P < 0.05)。表明许旺细胞复合小肠黏膜下层及碱性成纤维细胞生长因子缓释微球构建的人工神经可重建坐骨神经缺损后的神经传导通路。     

The controlled release study of Vincristine Sulfate

We prepared microspheres of Vincristine Sulfate (VCR) through drying-from-oil method, then mixed the microspheres into 0.7% collagen swelling solution to prepare emulsion, spread the emulsion on plate to form film by frozen-dry method. The film was cross-linked and sterilized, then planted into the site of tumor and expected to release at steady speed. We measured the release of VCR in vivo and in vitro by HPLC. The results demonstrated that VCR controlled release films release at approximate steady speed in 15 days.     

壳聚糖-明胶/聚乳酸-羟基乙酸联合载药水凝胶的体外抗结核作用

文题释义：基质细胞衍生因子1：是一种参与免疫细胞活化、分化和迁移及伤口愈合、角膜上皮再生和组织修复等过程的趋化因子,能促进干细胞的生长和发育,参与调节成骨分化,可通过细胞归巢提高干细胞向病灶区的趋化作用。而基质细胞衍生因子1的失活会损害成骨细胞的发育和分化。此外,其还与血管生成密切相关。 异烟肼：具有较高的杀菌活性,是治疗结核病的一线药物。世卫组织建议将异烟肼作为结核病的标准疗法,用于潜伏性结核病感染者的预防治疗,与利福平、吡嗪酰胺和乙胺丁醇一起用于治疗活动性肺结核。异烟肼的活化形式与脂肪酸生物合成Ⅱ型系统中的NADH依赖型烯醇酰基载体蛋白还原酶异烟肼a结合,阻断细菌细胞壁关键成分支原体酸的合成。 背景：抗结核化疗是目前治疗骨关节结核的主要手段,然而全身给药难以维持病灶区的有效浓度,治疗效果欠佳。 目的：制备一种原位、长期释放抗结核药物且兼备促成骨作用的壳聚糖-明胶/聚乳酸-羟基乙酸联合载药水凝胶。 方法：将亲水性的抗结核药物异烟肼和疏水性的基质细胞衍生因子通过复乳法负载到聚乳酸-羟基乙酸中,制备聚乳酸-羟基乙酸载药微球,共混至壳聚糖-明胶水凝胶支架中,制备壳聚糖-明胶/聚乳酸-羟基乙酸联合载药水凝胶。检测聚乳酸-羟基乙酸载药微球、壳聚糖-明胶/聚乳酸-羟基乙酸联合载药水凝胶的体外释药与抗结核杆菌的能力。将成骨前体细胞MC3T3-E1分别接种于载药微球与联合载药水凝胶表面,CCK-8法检测细胞活力,碱性磷酸酶活性检测细胞的成骨性能。 结果与结论：①载药微球中异烟肼1 h内的突释约为23.3%,2 d内的释放率约为42.6%,随后进入缓释期,25 d后进入平台期;基质细胞衍生因子1在1 h内的累积释放率约为19.8%,2 d内的释放率约为44.7%,随后进入缓释期,25 d后进入平台期;联合载药水凝胶中异烟肼和基质细胞衍生因子1最初1 h的释放分别为8.3%和8.5%,第2天的累计释放率分别为15.2%和17.6%,远低于聚乳酸-羟基乙酸微球;②体外4周后,联合载药水凝胶的抑菌直径大于载药微球,抑菌率高于载药微球(P < 0.05);③联合载药水凝胶与载药微球均具有良好的细胞相容性,细胞活力均约为100%;④培养5,10 d后,联合载药水凝胶表面的细胞碱性磷酸酶活性与载药微球比较差异无显著性意义(P > 0.05);⑤结果表明,原位壳聚糖-明胶/聚乳酸-羟基乙酸联合载药水凝胶有作为治疗骨关节结核及其他骨关节感染的潜力。 ORCID: 0000-0003-4166-2492(张贺龙) 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

Effects of dexamethasone-loaded PLGA microspheres on human fetal osteoblasts

Integration of a drug delivery function into implantable medical devices enables local release of specific bioactives to control cells-surface interactions. One alternative to achieve this biofunctionality for bone implants is to incorporate particulate drug delivery systems (DDSs) into the rough or porous implant surfaces. The scope of this study was to assess the effects of a model DDS consisting of poly(D,L-lactide-co-glycolide) (PLGA) microspheres loaded with an anti-inflammatory drug, dexamethasone (DXM), on the response of Simian Virus-immortalized Human Fetal Osteoblast (SV-HFO) cells. The microspheres were prepared by the oil-in-water emulsion/solvent evaporation method, whereas cells response was investigated by Alamar Blue test for viability, alkaline phosphatase (ALP) activity for differentiation, and Alizarin Red staining for matrix mineralization. Cell viability was not affected by the presence of increased concentrations of polymeric microspheres in the culture media. Furthermore, in the cultures with DXM-loaded microspheres, ALP activity was expressed at levels similar with those obtained under osteogenic conditions, indicating that DXM released from the microsphere-stimulated cell differentiation. Matrix mineralization occurred preferentially around the DXM-loaded microspheres confirming that the released DXM could act as osteogenic supplement for the cells. These in vitro findings suggest that a particulate PLGA-DXM DDS may actually provide dual, anti-inflammatory and osteogenic functions when incorporated on the surface of bone implants.     

Effects of basic fibroblast growth factor and transforming growth factor-beta on maturation of human pediatric aortic cell culture for tissue engineering of cardiovascular structures

Optimal in vitro conditions are necessary for the development of a strong, well structured, and functional tissue engineered cardiovascular structure eventually designed for implantation. To further optimize in vitro conditions for cell proliferation and extracellular matrix formation in tissue engineering of cardiovascular structures, in this study, ascorbic acid and growth factors as additives to standard cell culture medium were evaluated for their effect on tissue development in vitro. Biodegradable polymer patches [polyglycolic acid (PGA) coated with poly-4-hydroxybutyrate (P4HB)] were seeded with human pediatric aortic cells and cultured for 7 and 28 days. Group A was cultured with standard medium (DMEM with 10% fetal calf serum and 1% antibiotics) supplemented with ascorbic acid; group B was cultured with standard medium plus ascorbic acid and basic fibroblast growth factor (bFGF); group C was cultured with standard medium adding ascorbic acid and transforming growth factor (TGF). Analysis of the cell seeded polymer constructs included DNA assay, collagen assay, and histologic and immunohistochemical examination for cell proliferation and collagen formation. After 7 and 28 days of culture, group B and group C showed a significantly higher DNA content compared with group A. The addition of bFGF (group B) led to a markedly higher collagen synthesis after 28 days of culture compared with the additives in groups C and A. The histologic and immunohistochemical examination also revealed a more dense, organized tissue development with pronounced matrix protein formation in the tissue engineered structures in group B after 28 days of culture. When seeded on to the polymeric scaffold, human vascular cells proliferate and form organized cell tissue after 28 days of culture. The addition of bFGF and ascorbic acid to the standard medium enhances cell proliferation and collagen synthesis on the biodegradable polymer, which leads to the formation of more mature, well organized tissue engineered structures.     

In Vivo Validation of Biological Responses of bFGF Released from Microspheres Formulated by Blending Poly-Lactide-co-Glycolide and Poly(ethylene glycol)-Grafted-Chitosan in Hamster Cheek Pouch Microcirculatory Models

Microspheres formulated from blending poly(lactide-co-glycolide) (PLGA) and poly(ethylene glycol)-grafted-chitosan (PEG-g-CHN), using a modified in-emulsion-solvent-evaporation method, were investigated for the delivery of protein. A model protein, bovine serum albumin (BSA), was incorporated into the PLGA/PEG-g-CHN microspheres and both initial burst and release kinetics could be modulated by varying the PEG-g-CHN content. Basic fibroblast growth factor (bFGF) was formulated into the microspheres containing 5% PEG-g-CHN and the bFGF contents in the releasates were determined by a receptor-based ELISA with their in vitro bioactivities validated by fibroblast cell culture. The in vivo effect of the bFGF microspheres formulation was evaluated in a hamster cheek pouch model using a 7 day exposure (e.g., before significant vascular remodeling was expected). Using intravital microscopy, the tissue showed no evidence of inflammation with any formulation; deliberate activation of a preconditioning response linked to inflammation was attenuated by BSA microspheres alone. Vasoactive responses (receptor-dependant and independent constriction and dilation) linked to nitric oxide were attenuated, and constriction to endothelin was enhanced in bFGF and not BSA containing microspheres. PLGA/PEG-g-CHN blended microspheres were also demonstrated to be non-inflammatory and non-thrombogenic in vivo by observing the vascular changes in the cheek pouch. In conclusion, the addition of PEG-g-CHN to PLGA microspheres can serve as a sustained delivery vehicle for bFGF and the released protein provides vasoactive changes consistent with chronic bFGF exposure.     

Prolonged cytotoxic effect of colchicine released from biodegradable microspheres

One the main problems of cancer chemotherapy is the unwanted damage to normal cells caused by the high toxicities of anticancer drugs. Any system of controlled drug delivery that would reduce the total amount of drug required, and thus reduce the side effects, would potentially help to improve chemotherapy. In this respect, biodegradable gelatin microspheres were prepared by water/oil emulsion polymerization and by crosslinking with glutaraldehyde (GTA) as the drug-carrier system. Microspheres were loaded with colchicine, a model antimitotic drug, which was frequently used as an antimitotic agent in cancer research involving cell cultures. Microsphere sizes, swelling and degradation properties, drug-release kinetics, and cytotoxities were studied. Swelling characteristics of microspheres changed upon changing GTA concentration. A decrease in swelling values was recorded as GTA crosslink density was increased. In vitro drug release in PBS (0.01M, pH 7.4) showed rapid colchicine release up to approximately 83% (at t = 92 h) for microspheres with low GTA (0.05% v/v), whereas a slower release profile (only approximately 39%) was obtained for microspheres with high GTA (0.50% v/v) content, for the same period. Cytotoxicity tests with MCF-7, HeLa and H-82 cancer cell lines showed that free colchicine was very toxic, showing an approximately 100% lethal effect in both HeLa and H-82 cell lines and more than 50% decrease in viability in MCF-7 cells in 4 days. Indeed, entrapped colchicine indicated similar initial high toxic effect on cell viability in MCF-7 cell line and this effect became more dominant as colchicine continued to be released from microspheres in the same period. In conclusion, the control of the release rate of colchicine from gelatin microspheres was achieved under in vitro conditions by gelatin through the alteration of crosslinking conditions. Indeed, the results suggested the potential application of gelatin microspheres crosslinked with GTA as a sustained drug-delivery system for anticancer drugs for local chemotherapy administrations.     

成骨生长肽壳聚糖-海藻酸钠微球的制备及体外检测

背景：成骨生长肽体外注射可以刺激外周血和骨髓细胞数增加,增加动物的骨量,加速骨折愈合,但因多肽不稳定性及注射应用不方便,限制了其临床应用。 目的：应用乳化交联法制备成骨生长肽壳聚糖-海藻酸钠缓释微球,并对其粒径、载药、体外释药、理化特性进行检测。 方法：以戊二醛作为交联剂,应用乳化交联法制备具有控制释放功能的负载成骨生长肽壳聚糖-海藻酸钠微球,显微镜及扫描电镜观察微球的形态和粒径;利用酶联免疫吸附实验动态检测成骨生长肽壳聚糖-海藻酸钠微球的载药率、包封率和缓释规律。 结果与结论：乳化交联法制备的壳聚糖-海藻酸钠微球,球形良好,球体表面有较多微孔,具有较高的包封率(>72%)。体外药物释放实验表明,成骨生长肽可以从壳聚糖-海藻酸钠微球中缓慢释放,整个释放过程可达49 d,累积释放率>85%。提示应用乳化交联法制备的负载成骨生长肽壳聚糖-海藻酸钠缓释微球,具有很好的控制释放成骨生长肽的能力。     

EGF和bFGF对成年大鼠神经干细胞增殖和分化的影响

本研究旨在探索可促进成年大鼠神经干细胞增殖并形成较多的克隆球以及其分化出较多神经元的因素。取成鼠前脑室下区的组织进行原代培养 ,将之分为三组分别加入 EGF、b FGF以及 EGF+ b FGF,观察克隆球的形成状况。一周后收集三组原代细胞克隆球 ,加入完全培养液 (仅含 10 %胎牛血清 )进行分化实验。分化 14 d后 ,分别用 MAP-2和 GFAP的单克隆抗体进行免疫荧光标记 ,计算阳性细胞数量。无血清培养结果显示 ,b FGF组和 EGF+ b FGF组原代培养液中形成的原代克隆球数量和直径的差别不明显 ,但都明显地大于 EGF组。免疫荧光结果显示 ,b FGF组和 EGF+ b FGF组中的克隆球分化出 MAP-2阳性神经元的数量明显多于 EGF组 ,而 EGF组则能产生较多的胶质细胞。提示 ,b F GF能促进成年大鼠神经干细胞增殖 ,所形成的细胞克隆球能分化为较多的神经元。