A novel artificial nerve graft for repairing longdistance sciatic nerve defects:a self-assembling peptide nanofiber scaffold-containing poly (lactic-co-glycolic acid) conduit

In this study, we developed a novel artificial nerve graft termed self-assembling peptide nanofiber scaffold （SAPNS）-containing poly（lactic-co-glycolic acid） （PLGA） conduit （SPC） and used it to bridge a 10-mm-long sciatic nerve defect in the rat. Retrograde tracing, behavioral testing and histomorphometric analyses showed that compared with the empty PLGA conduit implantation group, the SPC implantation group had a larger number of growing and extending axons, a markedly increased diameter of regenerated axons and a greater thickness of the myelin sheath in the conduit. Furthermore, there was an increase in the size of the neuromuscular junction and myofiber diameter in the target muscle. These findings suggest that the novel artificial SPC nerve graft can promote axonal regeneration and remyelination in the transected peripheral nerve and can be used for repairing peripheral nerve injury.

Fabrication and Characterization of Poly Lactic Acid Scaffolds by Fused Deposition Modeling for Bone Tissue Engineering

Three-dimensional porous poly-lactic acid(PLA) scaffold was fabricated using fused deposition modeling(FDM) method including 30%, 50% and 70% nominal porosity. Study of phases in initial polymeric material and printed scaffolds was done by X-ray diffraction(XRD), and no significant phase difference was observed due to the manufacturing process, and the poly-lactic acid retains its crystalline properties. The results of the mechanical properties evaluation by the compression test show that the mechanical properties of the scaffold have decreased significantly with increasing the porosity of scaffold. The microstructure of scaffolds were studied by scanning electron microscope(SEM), showing that the pores had a regular arrangement and their morphology changed with porosity change. The mechanical properties of the poly-lactic acid scaffolds printed using fused deposition modeling, can be adapted to the surrounding tissue, by porosity change.

A porous poly(lactic-co-glycolic acid) scaffold induces innervation in a rabbit model of disc degeneration following annular injury

BACKGROUND： A degradable poly（lactic-co-glycolic acid） （PLGA） scaffold has been used to construct a degradable porous scaffold. This template can simulate the in vivo microenvironment and promote tissue formation. OBJECTIVE： To observe the histopathological changes during degeneration and regeneration of the intervertebral disc, and to analyze the effects of a PLGA scaffold on nerve fiber ingrowth into the lesion in vivo. DESIGN, TIME AND SETTING： A randomized, controlled animal experiment was performed at the Orthopaedic Laboratory, Clinic Medical Research Institution, Sir Run Run Shaw Hospital, Zhejiang University, from December 2007 to July 2008. MATERIALS： PLGA （China Textile Academy）; growth-associated protein-43 （Life-span, USA）; and protein gene product 9.5 antibody （AbD, United Kingdom） were used in this study. METHODS： Three consecutive segments of the intervertebral disc of thirty-two healthy adult male New Zealand rabbits were exposed, comprising L3-4, L4-5 and L5-6. Experimental intervertebral disc （L4-5 and L5-6） models were established by two different methods. In the test （trephine ＋ scaffold） group, a 5-mm deep hole was drilled into the annulus fibrosus using a 3-mm diameter trephine, and the PLGA scaffold was implanted into the hole. In the acupuncture group, the remaining experimental intervertebral disc annulus fibrosus was damaged using a 16G needle at a depth of 5 mm. The L3-4 disc served as a control. MAIN OUTCOME MEASURES： Intervertebral disc degeneration was assessed using radiography, magnetic resonance imaging, and histological examination at various time points post-surgery. Nerve fiber ingrowth into the degenerated intervertebral disc was observed using immunohistochemical staining for growth-associated protein-43 and protein gene product 9.5. RESULTS： Compared with the normal controls, the heights of the damaged intervertebral discs were decreased, and T2 signal intensity was decreased in the test and acupuncture groups 2 weeks post-surgery. Intervertebral disc degeneration was faster in the test group than in the acupuncture group. PLGA was coated with newly formed tissue, gradually degraded, and absorbed, and could induce tissue ingrowth deep into the annulus fibrosus. Results of immunohistochemical staining showed that nerve fibers were distributed in newly formed tissue in the test group, and in the superficial layer or surrounding scar tissue in the acupuncture group. CONCLUSION： A porous PLGA scaffold provides an important biological channel to induce nerve fiber ingrowth deep into the degenerated intervertebral disc.

Multi-porous electroactive poly(L-lactic acid)/ polypyrrole composite micro/nano fibrous scaffolds promote neurite outgrowth in PC12 cells

In this study, poly（L-lactic acid）/ammonium persulfate doped-polypyrrole composite fibrous scaffolds with moderate conductivity were produced by combining electrospinning with in situ polymerization. PC12 cells were cultured on these fibrous scaffolds and their growth following electrical stimulation （0-20.0 μA stimulus intensity, for 1-4 days） was observed using inverted light microscopy, and scanning electron microscopy coupled with the MTT cell viability test. The results demonstrated that the poly（L-lactic acid）/ammonium persulfate doped-polypyrrole fibrous scaffold was a dual multi-porous micro/nano fibrous scaffold. An electrical stimulation with a current intensity 5.0- 10.0 μAfor about 2 days enhanced neuronal growth and neurite outgrowth, while a high current intensity （over 15.0 μA） suppressed them. These results indicate that electrical stimulation with a moderate current intensity for an optimum time frame can promote neuronal growth and neurite outgrowth in an intensity- and time-dependent manner.

Enhanced angiogenesis in porous poly(ε-caprolactone)scaffolds fortified with methacrylated hyaluronic acid hydrogel after subcutaneous transplantation

A composite scaffold composed of a porous scaffold and hydrogel filling can facilitate engraftment,survival,and retention in cell transplantation processes.This study presents a composite scaffold made of poly(ε-caprolactone)(PCL)and methacrylated hyaluronic acid(MeHA)hydrogel and describes the corresponding physical properties(surface area,porosity,and mechanical strength)and host response(angiogenesis and fibrosis)after subcutaneous transplantation.Specifically,we synthesise MeHA with different degrees of substitution and fabricate a PCL scaffold with different porosities.Subsequently,we construct a series of PCL/MeHA composite scaffolds by combining these hydrogels and scaffolds.In experiments with mice,the scaffold composed of 3%PCL and 10-100 kDa,degree of substitution 70%MeHA results in the least fibrosis and a higher degree of angiogenesis.This study highlights the potential of PCL/MeHA composite scaffolds for subcutaneous cell transplantation,given their desirable physical properties and host response.

Co-transplantation of neural stem cells and Schwann cells within poly （L-lactic-co-glycolic acid） scaffolds facilitates axonal regeneration in hemisected rat spinal cord

Background Various tissue engineering strategies have been developed to facilitate axonal regeneration after spinal cord injury. This study aimed to investigate whether neural stem cells （NSCs） could survive in poly（L-lactic-co-glycolic acid） （PLGA） scaffolds and, when cografted with Schwann cells （SCs）, could be induced to differentiate towards neurons which form synaptic connection and eventually facilitate axonal regeneration and myelination and motor function. Methods NSCs and SCs which were seeded within the directional PLGA scaffolds were implanted in hemisected adult rat spinal cord. Control rats were similarly injured and implanted of scaffolds with or without NSCs. Survival, migration, differentiation, synaptic formation of NSCs, axonal regeneration and myelination and motor function were analyzed. Student＇s t test was used to determine differences in surviving percentage of NSCs. One-way analysis of variance （ANOVA） was used to determine the differences in the number of axons myelinated in the scaffolds, the mean latency and amplitude of cortical motor evoked potentials （CMEPs） and Basso, Beattie ＆ Bresnahan locomotor rating scale （BBB） score. The X2 test was used to determine the differences in recovery percentage of CMEPs. Results NSCs survived, but the majority migrated into adjacent host cord and died mostly. Survival rate of NSCs with SCs was higher than that of NSCs without SCs （（1.7831±0.0402）% vs. （1.4911±0.0313）%, P 〈0.001）. Cografted with SCs, NSCs were induced to differentiate towards neurons and might form synaptic connection. The mean number of myelinated axons in PLGA＋NSCs＋SCs group was more than that in PLGA＋NSCs group and in PLGA group （（110.25±30.46） vs. （18.25±3.30） and （11.25±5.54）, P 〈0.01）. The percentage of CMEPs recovery in PLGA＋NSCs＋SCs group was higher than in the other groups （84.8% vs, 50.0% and 37.5%, P 〈0.05）. The amplitude of CMEPs in PLGA＋NSCs＋SCs group was higher than in the other groups （（1452.63±331.70） IJV vs. （428.84±193.01） IJV and （117.33±14.40） μV, P 〈0.05）. Ipsilateral retransection resulted in disappearance again and functional loss of CMEPs for a few days. But contralateral retransection completely damaged the bilateral motor function. Conclusions NSCs can survive in PLGA scaffolds, and SCs promote NSCs to survive and differentiate towards neurons in vivo which even might form synaptic connection. The scaffolds seeded with cells facilitate axonal regeneration and myelination and motor function recovery. But regenerating axons have limited contribution to motor function recovery.

A Study of Surface Modification of Poly(lactic-co-glycolic) Acid Using Argon Ion Irradiation

The effect of Argon ion irradiation to the surface properties of poly(lactic-co-glycolic) acid (PLGA) was studied. A beam of 170 keV Argon ions was implanted at different fluencies (1 × 1012, 1 × 1013, 1 × 1014, and 1 × 1015 ions/cm2). X-ray photoelectron spectroscopy (XPS) was used to analyze the evolution of the bonding microstructure of PLGA due to irradiation. Surface morphology was monitored using atomic force microscopy (AFM). AFM analysis shows that film roughness increased to maximum at the dose of 1 × 1014 ions/cm2 where the formations of hillocks were also detected. Hydrophilicity of PLGA is important for their applications in biomedicine such as bioscaffolds. Hydrophilicity was monitored using water contact angle measurements for both unmodified and ion-modified PLGA. It was observed that hydrophilicity of PLGA changes with the ion irradiation. This demonstrates that ion irradiation can be an alternative approach to control hydrophilicity of PLGA. PLGA scaffolds modified with ion irradiation could therefore be more suitable for the biomedical applications.

Long-term morphological evaluation of porous poly-DL-lactic acid for soft tissue augmentation

Soft tissues are important for aesthetic considerations in implant therapy. The purpose of this study was to investigate soft tissue augmentation by using porous poly-DL-lactic acid (PDLLA)shaped as a tablet, with a diameter of5.0 mmand a height of2.0 mm. Porous PDLLA was implanted between the periosteal and epithelial tissues in 25 rats that were sacrificed at 1, 2, 4, 12, and 24 weeks. The average height of the PDLLA scaffolds at approximately 24 weeks was 1.85 ±0.08 mm, and the molecular weight decreased with time. Sinusoidal capillaries at 1 week, connective tissues at 4 weeks, and necrotic tissues at 24 weeks were observed more than other periods. At 24 weeks, the connective tissue surviving in the pores was confirmed to contain blood vessels;therefore, blood vessels are considered to be critical for the survival of soft tissue in scaffold pores. In this study, PDLLA was found to be useful for soft tissue augmentation in the long term. Although the molecular weight of PDLLA decreased with time, the height of the PDLLA scaffolds was preserved. The connective tissue surviving in the pores of the scaffolds at 24 weeks were associated with blood vessels. Further studies are necessary to investigate the optimal scaffold shape and surface characteristics to improve the penetration of blood vessels.

热致自卷曲左旋聚乳酸/聚乳酸-羟基乙酸共聚物纳米纤维血管支架制备及其性能

为研究热致自卷曲与生长因子梯度化修饰对血管内皮化的促进作用,使用左旋聚乳酸(PLLA)和聚乳酸-羟基乙酸共聚物(PLGA)作为材料,通过静电纺丝技术制备了具有热致自卷曲特性的PLLA/PLGA纳米纤维血管支架。通过静电喷雾技术制备了梯度生长因子修饰血管支架内层,并对其自卷曲、微观结构、生物相容性及内皮化功能进行表征。结果表明:制备的PLLA/PLGA血管支架具备多层取向纳米纤维结构,厚度为(6.75±0.4)μm,具有出色的生物相容性,可在37℃条件下自卷曲成管状结构;血管支架内层膜对生长因子成功进行了梯度修饰,修饰后血管支架的细胞迁移距离是未修饰的3.5倍,从而加快了内皮细胞迁移,促进血管内层的快速内皮化。

低温冷凝沉积法3D打印骨组织工程左旋聚乳酸/珍珠粉复合支架

背景:大面积骨缺损的修复目前仍面临严峻挑战,研发可个性化定制、低成本且具有成骨诱导活性的组织工程支架用于骨修复意义深远。目的:探索低温冷凝沉积法实现3D打印含珍珠复合材料骨组织工程支架的工艺流程,并进一步测试该复合支架的理化性能和体外生物学功能。方法:采用研磨过筛法制备珍珠粉,将不同质量的珍珠粉加入左旋聚乳酸墨水中,使珍珠粉与左旋聚乳酸的质量比分别为0,0.1,0.2,0.3,0.5,采用低温冷凝沉积法3D打印左旋聚乳酸/珍珠粉复合支架。检测支架的微观形貌、抗压性能、水接触角、细胞相容性以及体外促成骨分化能力。结果与结论:①扫描电镜显示5组支架均有直径2μm甚至更小的微孔,形状不规则且相互连通;②5组支架均具有良好的抗压性能,其中珍珠粉0.5组支架的压缩强度高于其他4组支架(P<0.05),珍珠粉0.2组、珍珠粉0.5组的水接触角小于珍珠粉0组(P<0.01,P<0.001);③将骨髓间充质干细胞分别与5组支架共培养1,3,5 d,珍珠粉0.1组、珍珠粉0.2组、珍珠粉0.3组、珍珠粉0.5组培养3,5 d的细胞增殖均快于珍珠粉0组(P<0.05);培养1 d的活死染色显示,各组支架上的细胞数量较少,但均为活细胞;④将骨髓间充质干细胞分别接种至珍珠粉0组、珍珠粉0.1组支架表面进行成骨诱导分化,珍珠粉0.1组诱导4,6 d的碱性磷酸酶活性高于珍珠粉0组(P<0.05);⑤结果表明,左旋聚乳酸/珍珠粉复合支架具有良好的抗压强度、亲水性、细胞相容性与促成骨性能。

基质细胞衍生因子1修饰左旋聚乳酸多孔微球促进软骨细胞增殖和组织形成

背景:二维培养条件下的软骨细胞增殖及表型维持受限,多孔微球作为支架材料可提供三维培养环境,以更好地模拟体内生长条件。基质细胞衍生因子1是有强趋化效力的稳态细胞因子,能够促进细胞的黏附与增殖。目的:明确接枝基质细胞衍生因子1左旋聚乳酸多孔微球对软骨细胞生物学特性及软骨组织形成的影响。方法:(1)体外验证不同质量浓度基质细胞衍生因子1对兔软骨细胞增殖、迁移、表型维持的影响。(2)采用复乳法制备左旋聚乳酸多孔微球,利用碳二亚胺法将基质细胞衍生因子1接枝于左旋聚乳酸多孔微球上,通过酶联免疫吸附实验及孵育基质细胞衍生因子1特异荧光抗体验证接枝情况。(3)将兔软骨细胞分别接种于左旋聚乳酸多孔微球、接枝基质细胞衍生因子1左旋聚乳酸多孔微球上,检测细胞增殖与黏附。(4)在裸鼠背部皮下分别植入甲基丙烯酰胺基明胶-软骨细胞复合体(对照组)、左旋聚乳酸多孔微球-甲基丙烯酰胺基明胶-软骨细胞复合体(多孔微球组)、接枝基质细胞衍生因子1左旋聚乳酸多孔微球-甲基丙烯酰胺基明胶-软骨细胞复合体(多孔微球修饰组),8周后取材,分别进行组织学染色与成软骨相关基因qRT-PCR检测。结果与结论:(1)相较于0,1 000 ng/mL基质细胞衍生因子1,500 ng/mL基质细胞衍生因子1可促进软骨细胞的增殖与迁移,提升软骨细胞内Ⅱ型胶原、弹性蛋白、增殖细胞核抗原、Bcl-2 mRNA表达;(2)基质细胞衍生因子1成功接枝于左旋聚乳酸多孔微球上,接枝率为93.75%;(3)相较于左旋聚乳酸多孔微球,接枝基质细胞衍生因子1左旋聚乳酸多孔微球可促进软骨细胞的增殖、黏附;(4)裸鼠皮下植入8周后,相较于对照组、多孔微球组,多孔微球修饰组具有更明显的软骨陷窝结构、更丰富的软骨特异性基质和Ⅱ型胶原沉积,弹性蛋白、Ⅱ型胶原、增殖细胞核抗原、Bcl-2 mRNA表达升高。结果表明:接枝基质细胞衍生因子1左旋聚乳酸多孔微球有利于软骨细胞的黏附、增殖、表型维持以及体内软骨组织形成。

Mild hypothermia combined with a scaffold of Ng Rsilenced neural stem cells/Schwann cells to treat spinal cord injury

Because the inhibition of Nogo proteins can promote neurite growth and nerve cell differentiation, a cell-scaffold complex seeded with Nogo receptor （NgR）-silenced neural stem cells and Schwann cells may be able to improve the microenvironment for spinal cord injury repair. Previous studies have found that mild hypothermia helps to attenuate secondary damage in the spinal cord and exerts a neuroprotective effect. Here, we constructed a cell-scaffold complex consisting of a poly（D,L-lactide-co-glycolic acid） （PLGA） scaffold seeded with NgR-silenced neural stem cells and Schwann cells, and determined the effects of mild hypothermia combined with the cell-scaffold complexes on the spinal cord hemi-transection injury in the T9 segment in rats. Compared with the PLGA group and the NgR-silencing cells ＋ PLGA group, hindlimb motor function and nerve electrophysiological function were dearly improved, pathological changes in the injured spinal cord were attenuated, and the number of surviving cells and nerve fibers were increased in the group treated with the NgR-silenced cell scaffold ＋ mild hypothermia at 34℃ for 6 hours. Furthermore, fewer pathological changes to the injured spinal cord and more surviving cells and nerve fibers were found after mild hypothermia therapy than in injuries not treated with mild hypothermia. These experimental results indicate that mild hypothermia combined with NgR gene-silenced cells in a PLGA scaffold may be an effective therapy for treating spinal cord injury.

Physical and degradation properties of PLGA scaffolds fabricated by salt fusion technique

Tissue engineering scaffolds require a controlled pore size and interconnected pore structures to support the host tissue growth. In the present study, three dimensional （3D） hybrid scaffolds of poly lactic acid （PLA） and poly glycolic acid （PGA） were fabricated using solvent casting/particulate leaching. In this case, partially fused NaCl particles were used as porogen （200-300μ） to improve the overall porosity （≥90%） and internal texture of scaffolds. Differential scanning calorimeter （DSC） analysis of these porous scaffolds revealed a gradual reduction in glass transition temperature （Tg） （from 48°C to 42.5°C） with increase in hydrophilic PGA content. The potential applications of these scaffolds as implants were further tested for their biocompatibility and biodegradability in four simulated body fluid （SBF） types in vitro. Whereas, simulated body fluid （SBF） Type1 with the optimal amount of HCO 3 ions was found to be more appropriate and sensible for testing the bioactivity of scaffolds. Among three combinations of polymer scaffolds, sample B with a ratio of 75：25 of PLA： PGA showed greater stability in body fluids （pH 7.2） with an optimum degradation rate （9% to 12% approx）. X-ray diffractogram also confirmed a thin layer of hydroxyapatite deposition over sample B with all SBF types in vitro.

Fabrication, Crosslinking and in vitro Biocompatibility of a Novel Degradable Nano-structure Urethral Tubular Scaffold

A degradable poly（lactic-co-glycolic acid, LA：GA=80：20）（PLGA） urethral tubular scaffold was fabricated by electrospinning. In order to enhance the mechanical properties, the scaffold was crosslinked with glutaraldehyde. The structure and properties of the crosslinked scaffolds were investigated by the mechanical property testing, scanning electron microscopy（SEM）, degradability test in vitro and 3-（4,5）-dimethylthiahiazo（-z-yl）-3,5-diphenytetrazo- liumromide（MTT）. The results show that the scaffold has the nano-structure. The pore size and the porosity are suitable for cell seeding, growth and extracellular matrix production. Although influenced by the crosslinking slightly, the pore size and the porosity could still support cell proliferation and tissuse formation. The mechanical properties are remarkably increased by the crosslinking of glutaraldehyde, and it could meet the demands of a urethral stent. The scaffold could completely collapse within 70 d. The results of the biocompatibility test show that the PLGA scaffold had no cytotoxicity.

Dexamethasone-Loaded PLGA Microspheres Incorporated PLLA/PLGA/PCL Composite Scaffold for Bone Tissue Engineering

The combination of micro-carriers and polymer scaffolds as promising bone grafts have attracted considerable interest in recent decades.The poly(L-lactic acid)/poly(lactic-co-glycolic acid)/polycaprolactone(PLLA/PLGA/PCL)composite scaffold with porous structure was fabricated by thermally induced phase separation(TIPS).Dexamethasone(DEX)was incorporated into PLGA microspheres and then loaded on the PLLA/PLGA/PCL scaffoldtopreparethedesiredcompositescaffold.The physicochemical properties of the prepared composite scaffold were characterized.The morphology of rat bone marrow mesenchymal stem cells(BMSCs)grown on scaffolds was observed using scanning electron microscope(SEM)and fluorescence microscope.The resultsshowedthatthePLLA/PLGA/PCLscaffoldhad interconnected macropores and biomimetic nanofibrous structure.In addition,DEX can be released from scaffold in a sustained manner.More importantly,DEX loaded composite scaffold can effectively support the proliferation of BMSCs as indicated by fluorescence observation and cell proliferation assay.The results suggested that the prepared PLLA/PLGA/PCL composite scaffold incorporating drug-loaded PLGA microspheres could hold great potential for bone tissue engineering applications.

Highly interconnected macroporous MBG/PLGA scaffolds with enhanced mechanical and biological properties via green foaming strategy

In this study,mesoporous bioactive glass particles(MBGs) are incorporated into poly(lactic-co-glycolic acid)(PLGA) to fabricate highly interconnected macroporous composite scaffolds with enhanced mechanical and biological properties via a developed supercritical carbon dioxide(scCO_(2)) foaming method Scaffolds show favorable highly interconnected and macroporous structure through a high foaming pressure and long venting time foaming strategy.Specifically,scaffolds with porosity from 73% to 85%,pore size from 120 μm to 320 μm and interconnectivity of over 95% are controllably fabricated at MBG content from 0 wt% to 20 wt%.In comparison with neat PLGA scaffolds,composite scaffolds perform improved strength(up to 1.5 folds) and Young's modulus(up to 3 folds).The interconnected macroporous structure is beneficial to the ingrowth of cells.More importantly,composite scaffolds also provide a more promising microenvironment for cellular proliferation and adhesion with the release of bioactive ions.Hopefully,MBG/PLGA scaffolds developed by the green foaming strategy in this work show promising morphological,mechanical and biological features for tissue regeneration.

Interaction of Immune System Protein with PEGylated and Un-PEGylated Polymeric Nanoparticles

Biodegradable Nanoparticles (NPs) are under intense investigation due to their potential application in targeted drug delivery. Upon their entry to the biological system, they encounter the immune system, which limits their availability at the intended site. Most importantly, the innate immune system is the one that acts as the first line of defense against foreign materials. It can be activated by collectin proteins which recognize the structural pattern of polysaccharide on the surface of microorganisms. NPs may interact with these proteins in a similar way, and the interaction may lead to beneficial outcomes in vaccine delivery. On the other hand, in targeted drug delivery, it is desirable for the NPs not to be recognized as foreign material as this may lead to their fast elimination from the system through mechanism such as opsonization. We investigated the interaction of PEGylated and un-PEGylated PLGA NPs with Recombinant Human Mannose-Binding Protein (HMBP) in an effort to understand the effect of surface modification on their binding to the protein. Results show that both PLGA-COOH and PLGA-PEG-NH2 bind to HMBP as studied using dynamic light scattering (DLS), fluoresce and UV-vis spectroscopy. However, their binding is shown to have different effect on the structure of the protein. Study done using fluorescence spectroscopy displayed a decrease in fluorescence emission of the protein upon binding to PLGA-COOH. On the other hand the fluorescence emission of the protein increased upon binding to the PLGA-PEG-NH2 indicating conformational changes in the protein structure.

Effect of PLA Knitted Structure on the Mechanical Properties of Composite Vascular Scaffold

A new entire biodegradable scaffold has been developed which does not require precellularization before transplantation.This new kind of vascular scaffold prototype made from porous poly-ε-caprolactone( PCL) membrane to provide three-dimensional environment for cell growth, and embedded with weft-knitted polylactic acid( PLA) fabric to support mechanics.The aim of this paper is to study the variation tendency of mechanical properties with the fabric spacing changing.The basic geometrical parameters were measured to characterize properties of the samples.The tensile and compressive elastic recovery of the samples were tested by the universal mechanical tester and radial compression apparatus,respectively.Both tensile and compressive properties enhanced when reducing the fabric spacing of the composite vascular scaffold.

载Apelin-13缓释微囊的新型生物支架促兔输卵管再通的初步研究

目的:输卵管炎性不孕症严重危害女性自然生育功能,临床迫切需求的真正意义上的输卵管再通包括病变输卵管解剖和功能的修复两方面,目前尚无有效的治疗方案。本研究旨在从这两方面探讨促进输卵管修复再通的方法。方法:制备Apelin-13缓释微囊和聚乳酸-羟基乙酸共聚物[poly(lactic-co-glycolic acid),PLGA]三维生物支架,检测生物支架的基本特性及体内降解情况(质量损失率),微囊的体外释药(累积释药率)、体内释药(Apelin-13血药浓度)及体外降解(降解率)情况。将Apelin-13微囊(微囊组)/载Apelin-13缓释微囊的PLGA三维生物支架(支架微囊组)注入/置入慢性输卵管炎新西兰兔模型的输卵管,观察和比较对照组、模型组、微囊组和支架微囊组术后输卵管的通畅情况、镜下结构、雌激素受体和孕激素受体的阳性表达情况。结果:术后第4周时PLGA三维生物支架的质量损失率为98.66%,微囊的体外降解率为70.58%,Apelin-13缓释微囊30 d体外累计释药率达98.68%,Apelin-13血药浓度在5 d内达到峰值,并在25 d内保持稳定。与模型组和微囊组相比,支架微囊组术后输卵管管腔内炎症反应轻,输卵管通畅率高,雌激素受体和孕激素受体的表达水平高(均P<0.05),支架微囊组的各项指标接近对照组。结论:载Apelin-13缓释微囊的PLGA三维生物支架可全面修复输卵管的解剖结构和生理功能,有望真正有效实现炎性输卵管再通。