RBX-庆大霉素药物释放系统的研制及体外释放实验

目的 :研制复合bBMP的异种骨庆大霉素局部药物释放系统 ,为治疗开放性骨折提供简便有效方法。材料和方法 :以复合bBMP的异种骨为核心载体 ,采用明胶包裹法和聚已内酯 (Poly ε caprolacton ,PCL)多重包裹法制成复合庆大霉素的植骨材料 ,对其进行表面结构和体外释放实验研究。结果 :2种方法制成的植骨材料均在 2 4h内有一爆发释放 ,并能维持一定时间的缓慢释放。其中PCL多重包裹法制成的RBX -G -LDDS在 2 5d时仍能达到 4.38ug/ml的释放浓度 ,高于庆大霉素对金黄色葡萄球菌的MIC(2ug/ml)。结论 :RBX -G -DDS具有良好的体外缓释特性 ,结合RBX的诱导成骨作用 ,能提供一种治疗开放性骨折的新方法     

聚内酯类生物降解性高分子微球可注射细胞支架

目的:用于组织工程化软骨、骨、脂肪等修复重建和整形用的可注射细胞支架.方法:以聚丙交酯(PLLA)、聚丙交酯/聚乙二醇共聚物(PLE),以及聚己内酯/聚乙二醇/聚丙交酯共聚物(PCEL)等聚内酯类生物降解高分子为基材,采用乳液-溶剂挥发法制成微米级大小、具有一定形态结构的微球.结果:聚内酯材料的组成对微球的形态结构有重要影响,微球的孔结构和稳定剂种类对微球的细胞亲和性有重要影响;含聚乙二醇成分的聚内酯材料可以形成呈多孔结构的微球,且以明胶为稳定剂制备的微球细胞亲和性更好.结论:聚内酯类生物降解高分子微球具有可注射性和良好的细胞亲和性,是一类具有应用前景的可注射细胞支架.     

生长因子在泌尿系统组织工程中的可控释放策略研究进展

外源性生长因子在泌尿系统组织工程研究中具有重要作用,但由于生长因子半衰期短,越来越多的研究利用各种控制释放载体,使生长因子在体内以恒定的速率缓慢而持续地释放,以保证其在支架材料中的含量,从而促进组织再生。本文就生长因子在泌尿系统组织工程中的控制释放策略的最新进展进行综述。     

载5-氟脲嘧啶聚己内酯纳米粒子对人胆管癌细胞的体外杀伤作用

目的:探讨聚己内酯载5-氟尿嘧啶(5-FU)纳米粒子对人胆管癌细胞株的体外杀伤作用、安全性及机制。方法:超声乳化法制备载5-FU聚己内酯纳米粒子(5-FU-PCL-NP),观察空载纳米粒子的体外溶血及5-FU-PCL-NP的体外药物释放情况,检测5-FU-PLA-NP对人胆管癌细胞株Hccc-9810增殖抑制及凋亡诱导作用。结果:5-FU-PCL-NP成功合成,其载药率为15.1%,包封率为41.9%,溶血试验阴性,5-FU-PCL-NP体外释放5-FU缓慢,其72 h释放率为62.9%。与单纯5-FU比较,5-FU-PCL-NP对Hccc-9810细胞的增殖抑制作用明显增强,IC50明显降低[(1.32±0.12)μg/m L vs.(2.5±0.39)μg/m L],促Hccc-9810细胞凋亡作用明显增强(均P0.05)。空载纳米粒对Hccc-9810细胞凋亡无明显影响(P0.05)。结论:载5-FU聚己内酯纳米粒子5-FU-PCL-NP具有良好的药物缓释效应,可延长5-FU的作用时间窗,对胆管癌细胞有较好的体外杀伤作用,且生物安全性好。     

生长因子缓释微球复合体在脂肪移植领域的研究进展

目的 综述生长因子缓释微球复合体在脂肪移植领域的研究进展。方法 广泛查阅近年来有关生长因子缓释微球复合体在脂肪移植领域的国内外文献并进行分析总结。结果 缓释微球载体材料包括天然高分子材料和合成高分子材料。不同缓释微球材料与不同生长因子相结合构成的缓释复合体能促进移植脂肪血管化,提高移植物的成活率,降低了液化、钙化和坏死等并发症的发生率。结论 生长因子缓释微球复合体因具有持续性和可控性等特点,已成为脂肪移植领域的研究热点,具有广阔应用前景。     

生长因子缓释微球复合体在脂肪移植领域的研究进展

目的综述生长因子缓释微球复合体在脂肪移植领域的研究进展。方法广泛查阅近年来有关生长因子缓释微球复合体在脂肪移植领域的国内外文献并进行分析总结。结果缓释微球载体材料包括天然高分子材料和合成高分子材料。不同缓释微球材料与不同生长因子相结合构成的缓释复合体能促进移植脂肪血管化,提高移植物成活率,降低液化、钙化和坏死等并发症的发生率。结论生长因子缓释微球复合体因具有持续性和可控性等特点,已成为脂肪移植领域的研究热点,具有广阔应用前景。     

人脂肪干细胞结合微载体在生物反应器中向软骨细胞分化

[目的]探索在旋转生物反应器内,应用微载体技术快速扩增并向软骨分化人脂肪干细胞。[方法]将人脂肪干细胞结合Cytodex3微载体在旋转的生物反应器(RCSS)内进行动态培养,应用倒置显微镜和扫描电镜对微载体表面的脂肪干细胞进行动态观察,并对收获的脂肪干细胞进行Safran in-O、tolu id ine b lue染色等组织化学染色及Ⅱ型胶原的免疫化学染色分析。[结果]脂肪干细胞于24 h内贴附于Cytodex3微载体表面,细胞形态为短梭形,随时间的延长,贴附于微载体的细胞逐渐增多,到培养后期,细胞密度可达最初接种的19倍左右,在微载体上收获的细胞进行番红花O、阿利新蓝染色呈阳性,Ⅱ型胶原染色阳性,均强于对照组。[结论]利用微载体细胞培养技术可简便快速地在体外扩增脂肪干细胞,并成功实现向软骨细胞分化。     

提高颗粒脂肪注射隆乳移植成活率和减少并发症的方法

目的：探索提高颗粒脂肪注射隆乳移植成活率和减少并发症的方法。方法：以肿胀法抽吸不同部位脂肪颗粒，经过分离纯化后，加入碱性成纤维细胞生长因子，分多层次扇形线状注射。结果：自2003年7月以来，应用脂肪抽吸，颗粒脂肪注射移植隆乳术48例，均获得良好效果，无一例出现感染、液化、硬结等并发症。结论：控制颗粒脂肪注射量、分离纯化、应用细胞生长因子、采用多层次多点注射以增加脂肪颗粒与受区组织的接触面积，是提高手术效果，减少并发症的有效方法。     

慢病毒载体介导的基因治疗在骨缺损修复中的研究进展

基因工程技术治疗骨缺损、骨坏死不仅可以持续、高效地于局部释放生长因子,而且其提供的内源性成骨生长因子较外源性生长因子具备更高的生物活性。慢病毒载体具有转染效率高、可持续稳定表达外源基因、增加调控基因后可调控目的蛋白的表达量、容纳大片段的外源性目的基因和安全性高等优点。将慢病毒介导的基因治疗手段应用到骨缺损治疗中具有较传统治疗方法无可比拟的优势和广阔的应用前景。本文就慢病毒载体应用在骨缺损基因治疗中的研究进展作一综述。     

聚己内酯／丝素蛋白／胶原电纺纤维的制备及其细胞相容性研究

目的：制备聚己内酯j丝素蛋白／胶原电纺纳米纤维支架,检测其对口腔黏膜j：皮细胞生长和增殖的影响。方法：将冉生丝素膜、水溶性胶原蛋白粉末及聚已内酯按质量比1：1：4;1：l：8;1：1：10共同溶于六氟异丙醇中。采用静电纺丝法制备制备聚己内酯/胶原／丝素蛋白电纺纳米纤维支架。将体外培养的口腔黏膜上皮细胞接种至材料表面,采用MTT法和扫描电镜研究口腔黏膜上皮细胞在材料表面的生长和增殖情况,评价聚己内酯／丝素蛋白/胶原电纺纳米纤维的细胞相容性。结果：MTT结果表明,口腔黏膜上皮细胞在聚己内酯/丝素蛋门／胶原电纺纳米纤维支架生长良好。电镜观察显示所制备的电纺纤维直径均一,呈相互连通的多孔网状结构。口腔黏膜上皮细胞在改性后的材料表面具有良好的生长形态。结论：聚己内酯/丝素蛋白/胶原电纺纳米纤维支架,具备合适的孔径和孔隙率,适合口腔黏膜。上皮细胞生长,细胞相容性良好,是一种组织工程尿道重建良好的支架载体。     

Selective release of cytokines,chemokines, and growth factors by minced skin in vitro supports the effectiveness of autologous minced micrografts technique for chronic ulcer repair

A new effective surgical procedure to repair chronic ulcers called minced micrografts technique has been recently reported. The technique consists in spreading a finely minced skin sample upon the wound bed. In this study, we investigate the in vitro release of cytokines (interleukin‐6, tumor necrosis factor‐α, interleukin‐1α, and granulocyte‐colony stimulating factor), chemokines (monocyte chemoattractant protein‐1 and growth‐related oncogene‐α), and growth factors (platelet‐derived growth factor, basic fibroblast growth factor, vascular endothelial growth factor, hepatocyte growth factor, and nerve growth factor) by minced (referred to as the minced sample) vs. not minced (referred to as the whole sample) human skin biopsy samples from the same donor. Factor release in the culture medium at different time points was detected using a multiplexed protein assay. The minced sample, which could behave like the skin fragments used in vivo in the autologous minced micrografts technique, expressed higher levels of tumor necrosis factor‐α, interleukin‐1α, platelet‐derived growth factor, and basic fibroblast growth factor, and lower levels of interleukin‐6, monocyte chemoattractant protein‐1, growth related oncogene‐α, and vascular endothelial growth factor compared with the whole sample. In conclusion, mincing of healthy skin may allow appropriate regulation of the inflammatory phase of wound healing and could induce overexpression of some growth factors, which facilitates the proliferative phase of healing.     

Vascular endothelial growth factor‐loaded poly(lactic‐co‐glycolic acid) microspheres‐induced lateral axonal sprouting into the vein graft bridging two healthy nerves: Nerve graft prefabrication using controlled release system

The most commonly used surgical technique for repairing segmental nerve defects is autogenous nerve grafting; however, this method causes donor site morbidity. In this study, we sought to produce prefabricated nerve grafts that can serve as a conduit instead of autologous nerve using a controlled release system created with vascular endothelial growth factor (VEGF)‐loaded poly(lactic‐co‐glycolic acid) (PLGA) microspheres. The study was performed in vitro and in vivo. For the in vitro studies, VEGF‐loaded PLGA microspheres were prepared. Thirty rats were used for the in vivo studies. Vein grafts were sutured between the tibial and peroneal nerves in all animals. Three groups were created, and an epineural window, partial incision, and microsphere application were performed, respectively. Walking track analysis, morphologic, and electron microscopic assessment were performed at the end of the eight weeks. Microspheres were produced in spherical shapes as required. Controlled release of VEGF was achieved during a 30‐days period. Although signs of nerve injury occurred initially in the partial incision groups according to the indexes of peroneal and tibial function, it improved gradually. The index values were not affected in the other groups. There were many myelinated fibers with large diameters in the partial incision and controlled release groups, while a few myelinated fibers that passed through vein graft in the epineural window group. Thereby, prefabrication was carried out for the second and third groups. It was demonstrated that nerve graft can be prefabricated by the controlled delivery of VEGF. © 2012 Wiley Periodicals, Inc. Microsurgery, 2012.     

载药磷酸钙骨水泥治疗慢性骨髓炎研究进展

抗生素缓释系统具有局部抗生素浓度高，全身毒副作用小，缓慢释放，持续时间长等优点，已逐渐成为治疗慢性骨髓炎的一种重要方法。载药磷酸钙骨水泥（CPC）具有药物载体和修复骨缺损的双重作用，且能诱导骨的生长并同步降解，是一种理想的安全可靠的抗生素缓释载体材料。在彻底病灶清除的基础上用载药CPC植入骨缺损处为治疗慢性骨髓炎的一种理想的行之有效的方法，具有操作简便、效果佳、住院时间短等优点。本文拟就载药磷酸钙骨水泥的生物特性、实验研究和临床应用等方面作一综述。     

bFGF壳聚糖微球的制备及检测

目的探讨以壳聚糖为载体、采用乳化交联法制备的bFGF壳聚糖微球体外释放特性,为下一步实验奠定基础。方法应用0.6%三聚磷酸钠溶液作为交联剂,1.5%壳聚糖溶液作为载体,采用乳化交联法制备bFGF壳聚糖微球。激光粒度及Zeta电位分析仪检测微球粒径分布,扫描电镜观察形态;ELISA法计算bFGF壳聚糖微球载药量、包封率及体外释药规律。结果 bFGF壳聚糖微球粒径为20.312～24.152μm;扫描电镜观察显示微球表面光滑圆整,无明显孔隙,分布均匀,分散性好。载药量和包封率分别为(7.57±0.34)mg/g及95.14%±1.58%。bFGF壳聚糖微球可持续体外释放bFGF 24 d;bFGF浓度随时间延长逐渐升高,第24天达(820.45±21.34)ng/mL;微球体外释药具有突释效应,突释率为18.08%,24 d累计释放率为82.05%。结论乳化交联法制备bFGF壳聚糖微球操作简便,微球表面光滑、分布均匀,分散性好,载药量和包封率均较高,体外释药较稳定且释放率较高,是一种较理想的制备bFGF壳聚糖微球的方法。     

The enhancement of nerve regeneration using growth factors: a brief review

The management of peripheral nerve injuries continues to challenge the surgeon. Despite advances in surgical technique, return of normal function is uncommon after the repair of a transected nerve. It is now possible to enhance the process of nerve regeneration in animals using growth factors carried in silicone nerve guides. In this article the biological process of nerve regeneration is described and contemporary research involving the use of growth factor implants to facilitate nerve regeneration is reviewed.     

神经生长因子对脊髓前角运动神经元的保护作用

目的：证实神经生长因子（ｎｅｒｖｅｇｒｏｗｔｈｆａｃｔｏｒ，ＮＧＦ）对脊髓前角运动神经元有保护作用。方法：切断ＳＤ大鼠一侧坐骨神经，借助单盲端硅胶管系统在神经损伤局部给予ＮＧＦ。术后行酶组织化学检测。结果：坐骨神经切断可致腰段脊髓前角运动神经元明显损害，其表现为神经元乙酰胆碱脂酶（ａｃｅｔｙｌ－ｃｈｏｌｉｎｅｓｔｅｒａｓｅ，ＡｃｈＥ）活性降低和酸性磷酸酶（ａｃｉｄｐｈｏｓｐｈａｔａｓｅ，ＡＣＰ）活性升高，应用ＮＧＦ可显著改善上述酶学变化。结论：ＮＧＦ对受伤的脊髓前角运动神经元有保护作用     

戊烷脒-EVA骨架释放体系的研究——EVA的弹性模量对释放的影响

本文报道抗纤溶剂戊烷脒从乙烯-醋酸乙烯酯(EVA)骨架体系中的释放行为。戊烷脒对EVA的渗透系数(D)及稳态流量(J_(lim))的测定结果表明释放机理是溶解控制释放。用EVA-琼脂骨架体系进行了溶胀实验,溶胀速率和溶胀程度随EVA的弹性模量而变化,较小的弹性模量得到较高的溶胀度从而导致较高的释放速度。弹性模量是影响EVA骨架体系药物释放速度的重要因素。     

Sustained release of nerve growth factor from biodegradable polymer microspheres.

Although grafted adrenal medullary tissue to the striatum has been used both experimentally and clinically in parkinsonism, there is a definite need to augment long-term survival. Infusion of nerve growth factor (NGF) or implantation of NGF-rich tissue into the area of the graft prolongs survival and induces differentiation into neural-like cells. To provide for prolonged, site-specific delivery of this growth factor to the grafted tissue in a convenient manner, we fabricated biodegradable polymer microspheres of poly(L-lactide)co-glycolide (70:30) containing NGF. Biologically active NGF was released from the microspheres, as assayed by neurite outgrowth in a dorsal root ganglion tissue culture system. Anti-NGF could block this outgrowth. An enzyme-linked immunosorbent assay detected NGF still being released in vitro for longer than 5 weeks. In vivo immunohistochemical studies showed release over a 4.5-week period. This technique should prove useful for incorporating NGF and other growth factors into polymers and delivering proteins and other macromolecules intracerebrally over a prolonged time period. These growth factor-containing polymer microspheres can be used in work aimed at prolonging graft survival, treating experimental Alzheimer's disease, and augmenting peripheral nerve regeneration.     

Antibiotic loaded chitosan bar. An in vitro, in vivo study of a possible treatment for osteomyelitis

A biodegradable drug delivery system of a gentamicin loaded chitosan bar with sustained antibiotic effect is described. Chitosan has proven to be a biocompatible aminopolysaccharide and a matrix for controlled release of pharmaceuticals. Combined crosslinking, solvent evaporation, and a cylinder model cutting technique was used to prepare the chitosan bar. Sustained diffusion of gentamicin into the surrounding medium was seen using a release test in vitro. Approximately 11% gentamicin was released from the bar in the first 24 hours. The gentamicin released from the bar showed significant antibacterial activity. The bar implanted in the proximal portion of the rabbit tibia produced a low blood concentration of gentamicin, but a much higher concentration was produced in local bone and in the hematoma. In all bone tissue around the bar, the gentamicin concentration exceeded the minimum inhibitory concentration for the common causative organisms of osteomyelitis for approximately 8 weeks. The implant caused no systemic side effects. Based on these test results together with the chitosan characteristics of biodegradable, antibiotic, and immunologic activity, the gentamicin loaded chitosan bar seems to be a clinically useful method for the treatment of bone infection. This system has an advantage over other systems in that it avoids a second operation for removal of the carrier.     

Liposomal Bupivacaine: Extended Duration Nerve Blockade Using Large Unilamellar Vesicles that Exhibit a Proton Gradient

Background: There is a clinical requirement for longer-acting local anesthetics, particularly for the management of postoperative and chronic pain. In this regard, liposomes have been suggested to represent a potentially useful vehicle for sustained drug release after local administration. In the current study, the authors used a transmembrane pH gradient to efficiently encapsulate bupivacaine within large unilamellar vesicles. They report on the kinetics of drug uptake and release and the duration of nerve blockade.

Methods: The rate and extent of bupivacaine uptake into large unilamellar vesicles that exhibit a pH gradient (interior acidic) were determined and compared to drug association with control liposomes that did not exhibit a proton gradient. In subsequent studies, researchers examined the kinetics of bupivacaine release from these liposome systems in vitro. Using the guinea pig cutaneous wheal model, the rate of clearance of the liposome carrier was monitored after intradermal administration, using a radiolabelled lipid marker, and the duration of nerve blockade produced by free and liposomal bupivacaine was compared.

Results: Bupivacaine was rapidly and efficiently accumulated within liposomes that exhibited a pH gradient (interior acidic) with trapping efficiencies of 64-82% of total drug, depending on the initial bupivacaine:phospholipid ratio. Little uptake was seen, however, for control vesicles that did not exhibit a transmembrane proton gradient. Using an in vitro model of drug clearance, liposomally encapsulated bupivacaine was found to be slowly released for a longer period of time compared with either the free drug or bupivacaine associated with control (no pH gradient liposomes). In the guinea pig cutaneous wheal model, more than 85% of the liposomal carrier was found to remain at the site of administration for 2 days. The sustained drug release afforded by liposomes that exhibited a pH gradient resulted in an increase in the duration of nerve blockade of as much as threefold compared with either the free drug or bupivacaine in the presence of control (no pH gradient) liposomes. Recovery of half maximal response (R2.5) after administration of 0.75% free bupivacaine, for example, was approximately 2 h, whereas the same dose of bupivacaine in pH gradient liposomes exhibited a R2.5 of approximately 6.5 h.