Biodegradable Polydioxanone Microspheres for Transcatheter Arterial Embolization: Proof of Principle

PurposeTo evaluate feasibility, embolization success, biodegradability, reperfusion, and biocompatibility of biodegradable microspheres (MS) made from polydioxanone (PDO) for transcatheter arterial embolization.Materials and MethodsUnilateral selective renal embolization of a segmental artery was performed in 16 New Zealand White rabbits with PDO-MS (100–150 μm and 90–315 μm). Animals were randomly assigned to different observation periods and underwent control digital subtraction angiography (DSA) and MR imaging immediately (n = 3), 1 week (n = 2), 4 weeks (n = 2), 8 weeks (n = 2), 12 weeks (n = 5), and 16 weeks (n = 2) after embolization. Kidneys were harvested for macroscopic and histologic analysis of embolization success, biodegradability, and biocompatibility.ResultsEmbolization was technically successful in 15 of 16 animals. One animal died of anesthesia-related circulatory failure. The 100–150 μm MS were injected easily through 3-F catheters; the 90–315 μm MS tended to clog with intermittent catheter obstruction. DSA and MR imaging showed successful target embolization in 13 of 15 animals. In 2 animals, the entire kidney was affected owing to catheter clogging, including a reflux of MS while flushing. Control DSA and MR imaging showed increasing vascular reperfusion with time. Macroscopic and histologic analysis revealed necrosis/infarction in areas in which embolization was achieved. MS were extensively degraded after 16 weeks, and overall inflammatory reaction was mild.ConclusionsBiodegradable PDO-MS induced effective embolization of target vessels while demonstrating good biocompatibility. MS increasingly dissolved at 16 weeks, partial reperfusion started at week 1, and complete reperfusion started at week 8, thus offering possible advantages as a temporary embolic agent.     

顺铂聚乳酸微球的药物释放特性及肝动脉栓塞研究

对顺铂聚乳酸微球进行了体外药物释放和家犬肝动脉栓塞研究。该微球粒径范围为50～200μm,平均粒径为115.76±35.94μm,顺铂含量为37.16%(W/W);体外药物释放机制符合Higuchi方程;肝动脉栓塞后8h,肝组织顺铂浓度高达21.55±12.18μg/g,明显高于肝动脉灌注顺铂组:3.16±0.09μg/g(P<0.05);肝动脉栓塞组的顺铂血浓峰值、各取血点浓度及曲线下面积AUC皆低于肝动脉灌注顺铂组。可望达到提高栓塞部位的药物疗效,降低全身毒副反应的作用。     

FK506-壳聚糖膜与体外培养雪旺细胞生物相容性的研究

目的 探讨FK506-壳聚糖膜片与培养的雪旺细胞生物相容性.方法 将生长状况和纯度较好的第3代雪旺细胞,分别传代接种于含有FK506-壳聚糖膜片、单纯壳聚糖膜片的培养皿中培养,以盖玻片作为对照组.计算3组雪旺细胞倍增时间、雪旺细胞纯度;用MTT法比较不同膜片上雪旺细胞的生长活力,绘制生长曲线;S-100免疫荧光染色.结果 雪旺细胞倍增时间对照组为5.9 d,单纯壳聚糖膜片及FK506-壳聚糖膜片组均为4.0 d;雪旺细胞纯度分别为80%、89%,93%;雪旺细胞增殖情况以FK506-壳聚糖组最佳,单纯壳聚糖组次之,对照组最差;各组雪旺细胞均呈S-100阳性,FK506-壳聚糖组与单纯壳聚糖组雪旺细胞排列呈典型的漩涡状或栅栏状.结论 FK506-壳聚糖膜片具有更显著的组织相容性与生物功能性,并保持了雪旺细胞的生物学特性.     

复方壳多糖组织工程皮肤的组织学特性

目的评价制备的复方壳多糖组织工程皮肤在组织学方面的特性，为其修复皮肤缺损创面提供实验依据。方法通过苏木精-伊红（HE）染色、高碘酸-希夫（PAS）染色、免疫组织化学染色及电镜，观察组织工程皮肤的组织学特征，包括表皮、真皮及两者的连接结构基底膜。结果制备的复方壳多糖组织工程皮肤表皮细胞增殖活跃，分层分化良好，厚约150μm，真皮层细胞生长正常，排列有序。PAS染色示真表皮间有均匀红染的条带出现，免疫组织化学染色结果显示Ⅳ型胶原、Ⅶ型胶原、层黏蛋白反应阳性，在电镜下可见角质形成细胞间大量桥粒，基底层内侧较多半桥粒，与机体皮肤结构相似。结论复方壳多糖组织工程皮肤组织结构良好，符合新型皮肤替代物在治疗皮肤缺损时的组织学要求。     

脱乙酰壳聚糖-抗坏血酸盐促进腭裂术后愈合的药效学研究

目的 腭裂手术创口是一类不易愈合的创口，为促进腭裂术后创口愈合速度与质量，减少术后复裂率，在腭裂动物模型上对脱已酰壳聚糖的作用进行药效学研究。方法 选20只Wistar大鼠随机分4组，以两种不同术式的实验组与相应的对照组进行实验。术后1、3、5、7、10天分别进行，)盏床观察和组织病理学观察。结果 实验组1，术后1天创面有缺血，3和5天粘膜颜色基本正常，7和10天拆线后的创口均为一期愈合。对照组1，术后1天创面有缺血，3和5天创缘糜烂，7天减轻，10天拆线创口二期愈合。实验组2与其对照组均有显著差异。组织病理，实验组1和组2重建覆盖上皮较对照组出现的早，实验组2缺损断端有新形成的骨组织连接，新骨周边可见成骨细胞，对照组1，有成纤维连接和炎细胞浸润。对照组2，缺损断处有新形成的软骨细胞，有炎细胞浸润。结论 脱已酰壳聚糖对腭裂术后的愈合有较明显的作用，有深入研究和临床应用的价值。     

In vivo induction of CD4+ T cell responses by antigens covalently linked to synthetic microspheres does not require adjuvant

Macrophages, dendritic cells or B lymphocytes have been shownto play a major role in the presentation of soluble antigensto CD4⁺ T cells. In contrast, the capacity of these cells topresent particulate antigens such as bacterial or parasiticantigens to T cells remains controversial. To investigate thisquestion, well defined particulate antigens were prepared bycovalent linkage of proteins or peptides to 1 µm in diametersynthetic microspheres. The T cell immunogenicity of such particulateantigens was analyzed in vitro and in vivo. In vitro, a solubleprotein such as hen egg lysozyme (HEL) coupled to beads stimulateda strong proliferative T cell response of lymph node cells fromHEL-primed mice or of specific T cell hybridomas. HEL coupledto beads was presented to the specific T cell hybridomas bysplenocytes or by peritoneal macrophages, but not by lymphomaB cells. Immunization of mice with several different proteinantigens or with a synthetic peptide covalently linked to beadsinduced strong CD4⁺ T cell responses in the absence of adjuvant.The strong in vivo immunogenicity of proteins coupled to beadsdid not result from a non-specific adjuvant effect of beadssince covalent linkage of the antigen to beads was strictlyrequired to induce T cell responses in the absence of adjuvant.In vivo treatment by carrageenan showed that macrophages arerequired for the in vivo stimulation of T cell responses bythese particulate antigens. Thus, these results demonstratedthe role of phagocytic cells, especially macrophages, for invivo presentation of particulate antigens. These particulateantigens represent an interesting approach for the developmentof new vaccines, and for the in vivo analysis of the role ofvarious antigen presenting cells in T cell activation and differentiation.     

免疫磁性捕获ELISA法检测甘草中甘草蛋白的研究

目的 制备甘草蛋白免疫磁性微球，并建立快速、精确的免疫磁性捕获ELISA法检测甘草蛋白。方法 采用种子聚合法合成聚苯乙烯磁性微球，并以兔抗甘草蛋白IgG抗体致敏，制备特异性捕获甘草特征蛋白的免疫磁性微球。以生物素标记抗体为示踪抗体，结合辣根过氧化物酶标亲和素建立ELISA检测系统，用于甘草药材和含甘草中成药中甘草蛋白的分析。结果 利用该方法对甘草药材和中成药中甘草蛋白抗原检测，检测灵敏度达到10ng／mL。结论 免疫磁性捕获ELISA检测技术方便、快速、准确，为生药的品种鉴定及中成药的质量控制提供一种新方法。     

蜂毒素微球经动脉介入治疗大鼠肝癌的实验研究

目的:观察蜂毒素微球(M-MS)经动脉介入对大鼠肝癌的治疗作用.方法:采用改良的复乳-液中干燥法制备蜂毒素-聚乳酸/羟乙酸微球,建立大鼠移植性肝癌模型并随机分为四组,分别经肝动脉灌注生理盐水(NS,1.5ml/kg)、蜂毒素(Melittin,0.35mg/kg)、空白微球(B-MS,10mg/kg)和蜂毒素-聚乳酸/羟乙酸微球(10mg/kg).比较治疗后各组大鼠的肿瘤生长情况、肿瘤坏死程度和生存时间.结果:与生理盐水组比较,Melittin组、B-MS组肿瘤生长受到明显抑制(P<0.01),肿瘤坏死程度以轻中度为主,但两组动物生存时间均未能明显延长(P>0.05).M-MS组与NS组、Melittin组及B-MS组相比,肿瘤生长抑制显著(P<0.01),肿瘤坏死更广泛、更彻底,且经蜂毒素微球治疗的大鼠生存期显著延长(P<0.01).结论:蜂毒素以药物微球的剂型经肝动脉给药,抗肿瘤效果明显优于单纯的蜂毒素和空白微球.     

戊二醛交联提高胶原/壳聚糖真皮支架抗细胞收缩能力的研究

目的 应用交联处理的胶原支架,来减缓其降解过多、易收缩变形、机械性能不足等缺点.方法 采用冷冻-冻干法构建胶原/壳聚糖多孔支架,并通过戊二醛交联构建具有良好抗细胞收缩稳定性和细胞相容性的胶原支架.通过测定不同培养时间各类支架的尺寸变化,研究了戊二醛交联对支架抗细胞收缩能力的影响.结果 戊二醛交联后的胶原/壳聚糖支架未见明显收缩,其细胞活性也始终高于干热交联支架.结论 戊二醛能有效地提高胶原基支架的抗细胞收缩能力,并保持其良好的生物相容性.