Small extracellular vesicles from hypoxia-preconditioned bone marrow mesenchymal stem cells attenuate spinal cord injury via miR-146a-5p-mediated regulation of macrophage polarization

Spinal cord injury is a disabling condition with limited treatment options.Multiple studies have provided evidence suggesting that small extracellular vesicles(SEVs)secreted by bone marrow mesenchymal stem cells(MSCs)help mediate the beneficial effects conferred by MSC transplantation following spinal cord injury.Strikingly,hypoxia-preconditioned bone marrow mesenchymal stem cell-derived SEVs(HSEVs)exhibit increased therapeutic potency.We thus explored the role of HSEVs in macrophage immune regulation after spinal cord injury in rats and their significance in spinal cord repair.SEVs or HSEVs were isolated from bone marrow MSC supernatants by density gradient ultracentrifugation.HSEV administration to rats via tail vein injection after spinal cord injury reduced the lesion area and attenuated spinal cord inflammation.HSEVs regulate macrophage polarization towards the M2 phenotype in vivo and in vitro.Micro RNA sequencing and bioinformatics analyses of SEVs and HSEVs revealed that mi R-146a-5p is a potent mediator of macrophage polarization that targets interleukin-1 receptor-associated kinase 1.Reducing mi R-146a-5p expression in HSEVs partially attenuated macrophage polarization.Our data suggest that HSEVs attenuate spinal cord inflammation and injury in rats by transporting mi R-146a-5p,which alters macrophage polarization.This study provides new insights into the application of HSEVs as a therapeutic tool for spinal cord injury.

Nanofibrous Scaffold Containing Osteoblast-Derived Extracellular Matrix for the Proliferation of Bone Marrow Mesenchymal Stem Cells

Extracellular matrix( ECM) plays a prominent role in establishing and maintaining an appropriate microenvironment for tissue regeneration. The aims of this study were to construct a tissue engineered scaffold by reconstituting osteoblast cell-derived ECM( O-ECM) on the electrospun nanofibrous scaffold,and further to evaluate its subsequent application for promoting the proliferation of bone marrow mesenchymal stem cells( BMSCs). To engineer a biomimetic scaffold, calvarial osteoblasts and electrospun poly-llactic acid( PLLA) nanofibers were prepared and subjected to decellularize for O-ECM deposition. To evaluate and characterize the O-ECM/PLLA scaffold, the morphology was examined and several specific mark proteins of osteoblasts matrix were evaluated.Furthermore,the cell counting kit-8( CCK-8) assay was used to detect the proliferation of the BMSCs cultivated on the O-ECM/PLLA scaffold. The results indicated O-ECM/PLLA scaffold was loaded with Collagen I, Fibronectin, and Laminin, as the composition of the marrow ECM. After decellularization,O-ECM deposition was observed in O-ECM/PLLA scaffold. Moreover,the O-ECM/PLLA scaffold could significantly enhance the proliferation of BMSCs,suggesting better cytocompatibility compared to the other groups tested. Taken together,a biomimetic scaffold based on the joint use of O-ECM and PLLA biomaterials,which represents a promising approach to bone tissue engineering, facilitates the expansion of BMSCs in vitro.

Mitogen activated protein kinase signaling pathways participate in the active principle region of Buyang Huanwu decoction-induced differentiation of bone marrow mesenchymal stem cells

Our preliminary studies confirmed that an active principle region of Buyang Huanwu decoction, comprising alkaloid, polysaccharide, aglycon, glucoside and volatile oil, can induce bone marrow mesenchymal stem cell differentiation into neurons. Mitogen-activated protein kinase signaling was identified as one of the key pathways underlying this differentiation process. The present study shows phosphorylated extracellular signal-regulated protein kinase and phosphorylated p38 protein expression was increased after differentiation. Cellular signaling pathway blocking agents, PD98059 and SB203580, inhibited extracellular signal-regulated protein kinase and p38 in mitogen-activated protein kinase signaling pathways respectively, mRNA and protein expression of the neuronal marker, neuron specific enolase, and neural stem cell marker, nestin, were decreased in bone marrow mesenchymal stem cells after treatment with the active principle region of Buyang Huanwu decoction. Experimental findings indicate that, extracellular signal-regulated protein kinase and p38 in mitogen-activated protein kinase signaling pathways participate in bone marrow mesenchymal stem cell differentiation into neuron-like cells, induced by the active principle region of Buyang Huanwu decoction.

Differentiation of mesenchymal stem cells into neuronal cells on fetal bovine acellular dermal matrix as a tissue engineered nerve scaffold

The purpose of this study was to assess fetal bovine acellular dermal matrix as a scaffold for supporting the differentiation of bone marrow mesenchymal stem cells into neural cells fol-lowing induction with neural differentiation medium. We performed long-term, continuous observation of cell morphology, growth, differentiation, and neuronal development using several microscopy techniques in conjunction with immunohistochemistry. We examined speciifc neu-ronal proteins and Nissl bodies involved in the differentiation process in order to determine the neuronal differentiation of bone marrow mesenchymal stem cells. The results show that bone marrow mesenchymal stem cells that differentiate on fetal bovine acellular dermal matrix display neuronal morphology with unipolar and bi/multipolar neurite elongations that express neuro-nal-speciifc proteins, includingβIII tubulin. The bone marrow mesenchymal stem cells grown on fetal bovine acellular dermal matrix and induced for long periods of time with neural differen-tiation medium differentiated into a multilayered neural network-like structure with long nerve ifbers that was composed of several parallel microifbers and neuronal cells, forming a complete neural circuit with dendrite-dendrite to axon-dendrite to dendrite-axon synapses. In addition, growth cones with filopodia were observed using scanning electron microscopy. Paraffin sec-tioning showed differentiated bone marrow mesenchymal stem cells with the typical features of neuronal phenotype, such as a large, round nucleus and a cytoplasm full of Nissl bodies. The data suggest that the biological scaffold fetal bovine acellular dermal matrix is capable of supporting human bone marrow mesenchymal stem cell differentiation into functional neurons and the subsequent formation of tissue engineered nerve.

Umbilical cord fibroblasts: Could they be considered as mesenchymal stem cells?

In cell therapy protocols, many tissues were proposed as a source of mesenchymal stem cells(MSC) isolation. So far, bone marrow(BM) has been presented as the main source of MSC despite the invasive isolation pro-cedure related to this source. During the last years, the umbilical cord(UC) matrix was cited in different studies as a reliable source from which long term ex vivo prolif-erating fibroblasts were isolated but with contradictory data about their immunophenotype, gene expression profile, and differentiation potential. Hence, an inter-esting question emerged: Are cells isolated from cord matrix(UC-MSC) different from other MSCs? In this re-view, we will summarize different studies that isolated and characterized UC-MSC. Considering BM-MSC as gold standard, we will discuss if UC-MSC fulfill different criteria that define MSC, and what remain to be done in this issue.

Dynamic culture of a thermosensitive collagen hydrogel as an extracellular matrix improves the construction of tissue-engineered peripheral nerve

Tissue engineering technologies offer new treatment strategies for the repair of peripheral nerve injury, hut cell loss between seeding and adhesion to the scaffold remains inevitable. A thermosensitive collagen hydrogel was used as an extracellular matrix in this study and combined with bone marrow mesenchymal stem cells to construct tissue-engineered peripheral nerve composites in vitro. Dynamic culture was performed at an oscillating frequency of 0.5 Hz and 35° swing angle above and below the horizontal plane. The results demonstrated that bone marrow mesenchymal stem cells formed membrane-like structures around the poly-L-lactic acid scaffolds and exhibited regular alignment on the composite surface. Collagen was used to fill in the pores, and seeded cells adhered onto the poly-L-lactic acid fibers. The DNA content of the bone marrow mesenchymal stem cells was higher in the composites constructed with a thermosensitive collagen hydrogel compared with that in collagen I scaffold controls. The cellular DNA content was also higher in the thermosensitive collagen hydrogel composites constructed with the thermosensitive collagen hydrogel in dynamic culture than that in static culture. These results indicate that tissue-engineered composites formed with thermosensitive collagen hydrogel in dynamic culture can maintain larger numbers of seeded cells by avoiding cell loss during the initial adhe-sion stage. Moreover, seeded cells were distributed throughout the material.

Mesenchymal stem cell-derived extracellular vesicles:A promising therapeutic strategy in diabetic osteoporosis

Diabetic osteoporosis(DOP)is a serious complication of diabetes mellitus.It is urgent to explore efficient clinical treatment strategies for DOP.It has been found that mesenchymal stem cell-derived extracellular vesicles(MSC-EVs),as an emerging cell-free therapy,show great potential in DOP treatment.MSC-EVs can effectively promote bone formation,inhibit bone resorption,and modulate the inflammatory microenvironment by delivering cargoes of microRNAs,long non-coding RNAs,and proteins to target cells,thereby ameliorating bone loss in DOP.However,there are limited reports on the treatment of DOP with MSC-EVs.To evoke more attention to this potential strategy,this article summarised the extant literature on MSC-EVs for DOP to provide new directions for further research and to promote the application of MSC-EVs in the clinical management of DOP.

In vitro cartilage production using an extracellular matrix-derived scaffold and bone marrow-derived mesenchymal stem cells

Background Cartilage repair is a challenging research area because of the limited healing capacity of adult articular cartilage.We had previously developed a natural,human cartilage extracellular matrix （ECM）-derived scaffold for in vivo cartilage tissue engineering in nude mice.However,before these scaffolds can be used in clinical applications in vivo,the in vitro effects should be further explored.Methods We produced cartilage in vitro using a natural cartilage ECM-derived scaffold.The scaffolds were fabricated by combining a decellularization procedure with a freeze-drying technique and were characterized by scanning electron microscopy （SEM）,micro-computed tomography （micro-CT）,histological staining,cytotoxicity assay,biochemical and biomechanical analysis.After being chondrogenically induced,the induction results of BMSCs were analyzed by histology and Immunohisto-chemistry.The attachment and viability assessment of the cells on scaffolds were analyzed using SEM and LIVE/DEAD staining.Cell-scaffold constructs cultured in vitro for 1 week and 3 weeks were analyzed using histological and immunohistochemical methods.Results SEM and micro-CT revealed a 3-D interconnected porous structure.The majority of the cartilage ECM was found in the scaffold following the removal of cellular debris,and stained positive for safranin O and collagen Ⅱ.Viability staining indicated no cytotoxic effects of the scaffold.Biochemical analysis showed that collagen content was （708.2±44.7）μg/mg,with GAG （254.7±25.9） μg/mg.Mechanical testing showed the compression moduli （E） were （1.226±0.288） and （0.052±0.007） MPa in dry and wet conditions,respectively.Isolated canine bone marrow-derived stem cells （BMSCs） were induced down a chondrogenic pathway,labeled with PKH26,and seeded onto the scaffold.Immunofluorescent staining of the cell-scaffold constructs indicated that chondrocyte-like cells were derived from seeded BMSCs and excreted ECM.The cell-scaffold constructs contained pink,smooth and translucent cartilage-like tissue after 3 weeks of culture.We observed evenly distributed cartilage ECM proteoglycans and collagen type Ⅱ around seeded BMSCs on the surface and inside the pores throughout the scaffold.Conclusion This study stuggests that a cartilage ECM scaffold holds much promise for in vitro cartilage tissue engineering.

Human bone marrow mesenchymal stem cell-derived extracellular vesicles inhibit shoulder stiffness via let-7a/Tgfbr1 axis

Shoulder stiffness(SS)is a common shoulder disease characterized by increasing pain and limited range of motion.SS is considered to be an inflammatory and fibrotic disorder pathologically.However,there is no consensus on the most effective conservative treatment for fibrosis.Given that human Bone Marrow Mesen-chymal Stem Cell-derived extracellular vesicles(BMSC-EVs)displayed promising therapeutic effects for various tissues,we investigated the therapeutic effect of BMSC-EVs on fibrosis in a mice immobilization model and two cell models.By conducting a series of experiments,we found that BMSC-EVs can significantly inhibit the fibrogenic process both in vitro and in vivo.In detail,BMSC-EVs suppressed the aberrant proliferation,high collagen production capacity,and activation of fibrotic pathways in TGF-β-stimulated fibroblasts in vitro.Besides,in vivo,BMSC-EVs reduced cell infiltration,reduced fibrotic tissue in the shoulder capsule,and improved shoulder mobility.In addition,via exosomal small RNA sequencing and qPCR analysis,let-7a-5p was verified to be the highest expressed miRNA with predicted antifibrotic capability in BMSC-EVs.The antifibrotic capacity of BMSC-EVs was significantly impaired after the knockdown of let-7a-5p.Moreover,we discovered that the mRNA of TGFBR1(the membrane receptor of transforming growth factorβ)was the target of let-7a-5p.Together,these findings elucidated the antifibrotic role of BMSC-EVs in shoulder capsular fibrosis.This study clarifies a new approach using stem cell-derived EVs therapy as an alternative to cell therapy,which may clinically benefit patients with SS in the future.

Advancing application of mesenchymal stem cell-based bone tissue regeneration

Reconstruction of bone defects,especially the critical-sized defects,with mechanical integrity to the skeleton is important for a patient's rehabilitation,however,it still remains challenge.Utilizing biomaterials of human origin bone tissue for therapeutic purposes has provided a facilitated approach that closely mimics the critical aspects of natural bone tissue with regard to its properties.However,not only efficacious and safe but also costeffective and convenient are important for regenerative biomaterials to achieve clinical translation and commercial success.Advances in our understanding of regenerative biomaterials and their roles in new bone formation potentially opened a new frontier in the fast-growing field of regenerative medicine.Taking inspiration from the role and multicomponent construction of native extracellular matrix(ECM)for cell accommodation,the ECM-mimicking biomaterials and the naturally decellularized ECM scaffolds were used to create new tissues for bone restoration.On the other hand,with the going deep in understanding of mesenchymal stem cells(MSCs),they have shown great promise to jumpstart and facilitate bone healing even in diseased microenvironments with pharmacology-based endogenous MSCs rescue/mobilization,systemic/local infusion of MSCs for cytotherapy,biomaterials-based approaches,cell-sheets/-aggregates technology and usage of subcellular vesicles of MSCs to achieve scaffolds-free or cell-free delivery system,all of them have been shown can improve MSCsmediated regeneration in preclinical studies and several clinical trials.Here,following an overview discussed autogenous/allogenic and ECM-based bone biomaterials for reconstructive surgery and applications of MSCsmediated bone healing and tissue engineering to further offer principles and effective strategies to optimize MSCs-based bone regeneration.

羊膜细胞外基质与膀胱细胞外基质材料修复大鼠子宫内膜损伤

背景:大量研究已证实,羊膜细胞外基质与膀胱细胞外基质材料均可作为干细胞载体用于子宫内膜损伤的治疗,但是有关两种材料的比较研究相对少见。目的:对比羊膜细胞外基质与膀胱细胞外基质材料作为干细胞载体治疗子宫内膜损伤的差异。方法:采用全骨髓贴壁法分离纯化SD大鼠骨髓间充质干细胞。分别制备SD大鼠羊膜细胞外基质与膀胱细胞外基质材料,然后将骨髓间充质干细胞分别接种于两种材料表面,检测细胞增殖与黏附情况。将40只SD大鼠随机分为4组(n=10),除假手术组外,子宫内膜损伤组、羊膜细胞外基质组、膀胱细胞外基质组均通过机械干预的方式建立子宫内膜损伤模型,分别将羊膜细胞外基质/骨髓间充质干细胞复合物、膀胱基质细胞外基质/骨髓间充质干细胞复合物移植至羊膜细胞外基质组、膀胱细胞外基质组大鼠损伤内膜部位,移植后14,28 d取材检测,苏木精-伊红染色观察大鼠子宫内膜组织形态,酶联免疫吸附法分析子宫内膜组织中碱性成纤维细胞生长因子、胰岛素样生长因子1与血管内皮生长因子水平,免疫组化染色分析子宫内膜组织中波形蛋白与CD34表达。结果与结论:(1)两种细胞外基质材料均有利骨髓间充质干细胞的增殖,相较于膀胱细胞外基质材料,羊膜细胞外基质材料可促进骨髓间充质干细胞的黏附;(2)相较于假手术组,子宫内膜损伤组碱性成纤维细胞生长因子、胰岛素样生长因子1与血管内皮生长因子水平降低(P <0.01),子宫内膜组织形态发育不良,内膜厚度与腺体数量减少,波形蛋白与CD34阳性表达减少(P <0.01);相较于子宫内膜损伤组,羊膜细胞外基质组、膀胱细胞外基质组碱性成纤维细胞生长因子、胰岛素样生长因子1与血管内皮生长因子水平均升高(P <0.05或P <0.01),子宫内膜组织形态明显改善,内膜厚度与腺体数量增加,波形蛋白与CD34阳性表达增加(P <0.05或P <0.01),并且羊膜细胞外基质组的改善作用优于膀胱细胞外基质组(P <0.05);(3)结果表明,相较于膀胱细胞外基质材料,羊膜细胞外基质材料作为骨髓间充质干细胞的载体可进一步促进损伤子宫内膜的修复。

Evaluation of an extracellular matrix-derived acellular biphasic scaffold/cell construct in the repair of a large articular high-load-bearing osteochondral defect in a canine model

Osteochondral lesion repair is a challenging area of orthopedic surgery. Here we aimed to develop an extracellular matrix-derived, integrated, biphasic scaffold and to investigate the regeneration potential of the scaffold loaded with chondrogenically-induced bone marrow-derived mesenchymal stem cells （BMSCs） in the repair of a large, high-load-bearing, osteochondral defect in a canine model. Methods The biphasic scaffolds were fabricated by combining a decellularization procedure with a freeze-drying technique and characterized by scanning electron microscopy （SEM） and micro-computed tomography （micro-CT）. Osteochondral constructs were fabricated in vitro using chondrogenically-induced BMSCs and a biphasic scaffold, then assessed by SEM for cell attachment. Osteochondral defects （4.2 mm （diameter） ×6 mm （depth）） were created in canine femoral condyles and treated with a construct of the biphasic scaffold/chondrogenically-induced BMSCs or with a cell-free scaffold （control group）. The repaired defects were evaluated for gross morphology and by histological, biochemical, biomechanical and micro-CT analyses at 3 and 6 months post-implantation. Results The osteochondral defects of the experimental group showed better repair than those of the control group. Statistical analysis demonstrated that the macroscopic and histologic grading scores of the experimental group were always higher than those of the control group, and that the scores for the experimental group at 6 months were significantly higher than those at 3 months. The cartilage stiffness in the experimental group （6 months） was （6.95±0.79） N/mm, 70.77% of normal cartilage; osteochondral bone stiffness in the experimental group was （158.16±24.30） N/mm, 74.95% of normal tissue; glycosaminoglycan content of tissue-engineered neocartilage was （218±21.6） tJg/mg （dry weight）, 84.82% of native cartilage. Micro-CT analysis of the subchondral bone showed mature trabecular bone regularly formed at 3 and 6 months, with no significant difference between the experimental and control groups. Conclusion The extracellular matrix-derived, integrated, biphasic scaffold shows potential for the repair of large, high-load-bearing osteochondral defects.

Novel pre-vascularized tissue-engineered dermis based on stem cell sheet technique used for dermis-defect healing

Insufficient donor dermis and the shortage of three-dimensional vascular networks are the main limitations in the tissue-engineered dermis(TED).To solve these problems,we initially constructed pre-vascularized bone marrow mesenchymal stem cell sheet(PBMCS)and pre-vascularized fibroblasts cell sheet(PFCS)by cell sheet technology,and then superimposed or folded them together to construct a pre-vascularized TED(PTED),aiming to mimic the real dermis structure.The constructed PTED was implanted in nude mice dorsal dermis-defect wound and the wound-healing effect was quantified at Days 1,7 and 14 via the methods of histochemistry and immunohistochemistry.The results showed that PTED could rapidly promote the wound closure,especially at Day 14,and the wound-healing rate of three-layer PTED could reach 97.2%(P<0.01),which was faster than the blank control group(89.1%),PBMCS(92.4%),PFCS(93.8%)and six-layer PTED(92.3%).In addition,the vessel density in the PTED group was higher than the other groups on the 14th day.Taken together,it is proved that the PTED,especially three-layer PTED,is more conducive to the fullthickness dermis-defect repair and the construction of the three-dimensional vascular networks,indicating its potential application in dermis-defect repair.

转化生长因子β亚家族调控骨关节炎中的作用

背景:骨关节炎作为中国最常见的老年慢性退行性疾病之一,因其复杂的发病机制及细胞分子交流途径,目前尚未有行之有效的方法去延缓骨关节炎的进展。而转化生长因子β在早期关节的形成、骨和软骨的发育以及关节重塑各阶段发挥重要作用,是维持与调节关节稳态的关键因子之一。目的:综述近年来国内外关于转化生长因子β亚家族在骨关节炎的发生发展中所起到的调控作用,分析其在骨关节炎不同阶段所产生的影响,探究转化生长因子β在临床治疗骨关节炎上的应用前景,以期能为临床治疗方案提供参考。方法:应用计算机检索中国知网和PubMed数据库收录的相关文献,中文检索词为“骨关节炎,转化生长因子,信号通路,骨重塑,软骨退变,血管生成,治疗”,英文检索词为“Osteoarthritis,Transforming Growth Factor,Signaling Pathway,Bone Remodeling,Cartilage Degeneration,Angiogenesis,Treatment”,最终纳入57篇文献进行综述分析。结果与结论:(1)目前,关于骨关节炎复杂的发病机制尚未有统一定论,大量研究表明骨关节炎与细胞因子和信号通路关系密切,以转化生长因子β超家族作为其发病机制和治疗突破口的相关研究也是当前的热点。(2)转化生长因子β在早期关节软骨形成与稳态维持上起到关键作用,并对于软骨损伤修复有促进作用;而在关节成型后,转化生长因子β的保护作用会减弱甚至造成破坏效应,其双重调节作用也是目前转化为临床治疗手段的重点,需后续研究明确适用范围以制定标准。(3)高水平活性转化生长因子β在机械应力的介导下参与骨细胞、成骨细胞与破骨细胞的调控,并干预随后骨微观结构的重塑,特异性抑制剂可作为治疗疾病的靶向药物,但其作用的安全性与有效性仍需临床进一步完善。(4)血管增生可能在转化生长因子β介导软骨退变及软骨下骨重塑中提供潜在的串扰途径,异常的交流途径会进一步破坏骨软骨单元微环境的稳态从而加速骨关节炎中关键的病理学进展。(5)关于转化生长因子β在骨关节炎中的研究已经较为全面,临床应用前景广泛,目前已有相关药物处于临床试验阶段,但如何控制对其他组织的潜在影响和精准控制靶向递送等关键问题亟需解决,随着研究的深入,未来有望在延缓骨关节炎治疗方式上作出新的突破。

BMSCs外泌体miR-181通过靶向调控ERK5促进股骨骨折小鼠的成骨分化

目的:探讨BMSCs外泌体(BMSCs-Exos)对其体外成骨分化的调控作用,以及miR-181通过靶向ERK5实现的机制,并研究BMSCs-Exos和过表达miR-181对小鼠股骨骨折愈合的影响。方法:通过动态光散射(DLS)技术和Western blot法表征BMSCs-Exos,qRT-PCR和Western blot检测miR-181和ERK5表达,双荧光素酶报告基因实验验证miR-181对ERK5的调控。使用Western blot和ELISA检测蛋白表达和ALP活性。在小鼠股骨骨折模型中注射miR-181 mimic或BMSCs-Exos,通过骨痂体积(CV)、骨体积分数(BV/TV)和相关蛋白评估骨折愈合效果。结果:BMSCs-Exos的粒径范围为50~150nm,Zeta电势为-25.69±2.88mV,表面标志物CD9、CD63、CD81显著表达。BMSCs-Exos组中miR-181表达上调(P<0.05),ERK5表达下调(P<0.05);mimic上调了miR-181表达并降低ERK5蛋白表达(P<0.05)。BMSCs-Exos转运miR-181通过靶向调控ERK5促进BMSCs体外成骨分化(P<0.05),且BMSCs-Exos和过表达miR-181均促进小鼠股骨骨折愈合(P<0.05)。结论:BMSCs-Exos通过转运miR-181、靶向调控ERK5促进BMSCs体外成骨分化,并有助于小鼠股骨骨折愈合。

牙槽骨骨髓间充质干细胞膜片复合PCL/HA支架具有良好早期成骨效果:基于动物模型研究

目的评估牙槽骨骨髓间充质干细胞膜片复合PCL/HA支架的骨缺损再生修复效果。方法培养牙槽骨骨髓间充质干细胞(Al-BMSCs)膜片和长骨骨髓间充质干细胞(Lon-BMSCs)膜片,熔融沉积成型技术制作PCL/HA支架。取新西兰大白兔共9只,建立双侧下颌骨缺损模型,按植入材料将其分为PCL/HA支架组(A组)、Lon-BMSCs膜片复合PCL/HA支架组(B组)、Al-BMSCs膜片复合PCL/HA支架组(C组),3组共得到18个样本,6个/组。术后4周处死动物,取下颌骨组织,行大体观察、锥形束CT分析、HE染色和Masson染色,对各组成骨情况进行分析。结果锥形束CT结果显示C组骨体积分数、骨小梁厚度和骨小梁数量均高于A组和B组,组间差异有统计学意义(P<0.05)。HE和Masson染色显示C组成骨最为活跃,有较多的新生骨和血管形成。结论牙槽骨骨髓间充质干细胞膜片复合PCL/HA支架具有良好的早期成骨效果,为颌面部骨缺损再生修复提供了一种新的策略。

骨髓间充质干细胞外泌体调控NLRP3炎性小体对糖尿病大鼠牙槽骨缺损的机制研究

目的 探究骨髓间充质干细胞外泌体通过调控NLRP3炎性小体信号通路影响糖尿病大鼠牙槽骨缺损愈合相关分子机制。方法 选取50只SD大鼠纳入研究,随机选取10只大鼠作为对照组,其余大鼠构建糖尿病+双侧上颌牙槽骨缺损模型,设置模型组、骨髓间充质干细胞外泌体组(BMMSC-Exos组)、MCC950组(NLRP3抑制剂)、BMMSC-Exos+MCC950组,其中BMMSC-Exos组、MCC950组、BMMSC-Exos+MCC950组SD大鼠分别尾静脉注射BMMSC-Exos及MCC950试剂,模型组注射等量盐水。模型构建28d后取大鼠上颌骨组织。TEM检测BMMSC-Exos形态,Westernblot检测BMMSC-Exos标志性蛋白CD9、CD63、CD81表达。检测各组大鼠空腹血糖水平、HE染色分析各组大鼠牙槽骨炎性浸润及Lance-Sandhu评分;Western blot检测各组大鼠牙槽骨组织内NLRP3炎性小体信号通路关键蛋白(NLRP3、caspase-1、IL-1β)、骨代谢关键蛋白(OPG、ALP、Collal)表达。结果 BMMSC-Exos直径大小在100 nm左右,呈双凹圆盘状态,膜结构完整;与纯BMMSCs相比,BMMSC-Exos标志物蛋白CD9、CD63、CD81的含量表达明显提升(P <0.05)。糖尿病大鼠模型建立成功,BMMSC-Exos干预、NLRP3抑制剂(MCC950)下调大鼠血糖水平(P <0.05);两者联合可以进一步下调大鼠血糖水平(P <0.05);与对照组相比,糖尿病牙槽骨缺损模型建立可以下调骨再生Lane-Sandhu评分、OPG、ALP、Collal的表达(P <0.05),上调NLRP3、caspase-1、IL-1β表达(P <0.05);BMMSC-Exos干预可以再次上调Lane-Sandhu评分及OPG、ALP、Collal蛋白表达(P<0.05),下调NLRP3、caspase-1、IL-1β的表达(P <0.05)。与模型组相比,BMMSC-Exos及MCC950干预后大鼠骨再生Lane-Sandhu评分、骨代谢关键蛋白(OPG、ALP、Collal)的表达提升(P<0.05);两者联合可进一步上调大鼠骨再生Lane-Sandhu评分及骨代谢关键蛋白表达(P <0.05)。结论 骨髓间充质干细胞外泌体通过抑制NLRP3炎症小体活性来改善糖尿病牙槽骨缺损大鼠骨代谢,降低炎症反应,促进骨缺损的愈合。

大黄苷元对骨髓间充质干细胞移植脑缺血大鼠基质金属蛋白酶的影响

目的:观察大黄苷元对脑缺血再灌注损伤大鼠骨髓间充质干细胞(bone marrowstromal cells,BMSCs)移植术后脑组织病理改变及基质金属蛋白酶的影响。方法:体外全骨髓细胞贴壁筛选培养法扩增BMSCs;线栓法制备大脑中动脉阻塞(middle cerebral artery occlusion,MCAO)模型。190只大鼠随机分为假手术组、模型组、大黄苷元组、BMSCs移植组(简称移植组)和BMSCs移植联合大黄苷元组(简称联合组)。再灌注后24 h将BMSCs由同侧颈内动脉移植入移植组和联合组大鼠脑内;大黄苷元组和联合组予大黄苷元灌胃用药。移植后7、14和28 d,模型各组取脑组织用于检测。光镜下观察脑组织微血管病理改变;免疫组织化学法测定BMSCs免疫球蛋白抗体G(immunoglobulin G,IgG)、Ⅳ型胶原(type Ⅳ collagen,col Ⅳ)、基质金属蛋白酶9(matrix metalloproteinase-9,MMP-9)和金属蛋白酶组织抑制物1(tissue inhibitor of metalloproteinase-1,TI MP-1)的表达。结果:与正常对照组比较,模型组大鼠微血管残缺、破损明显,脑组织中IgG和MMP-9表达增强,ColⅣ和TI MP-1表达减弱。与模型组比较,大黄苷元组、移植组和联合组大鼠微血管结构改善明显;大黄苷元组和联合组各时间点大鼠脑组织中IgG表达和MMP-9活性减弱,ColⅣ和TI MP-1表达增强。联合组大鼠于移植7d时的微血管结构较移植组完整,其各时间点大鼠脑组织中ColⅣ表达较移植组增强,14 d时大鼠脑组织中MMP-9活性较大黄苷元组降低,TI MP-1表达增强,28 d时TI MP-1表达较移植组增强。结论:大黄苷元可使脑缺血再灌注损伤大鼠微血管基底膜ColⅣ降解减少,通透性降低,并与BMSCs有协同作用,其作用机制可能与增加TI MP-1表达以调节MMP-9平衡有关。

骨质疏松大鼠骨髓基质细胞膜片的体外构建研究

目的探讨骨质疏松大鼠骨髓基质细胞膜片的构建及基本生物学特性。方法建立大鼠绝经后骨质疏松症(PMOP)模型,分离培养骨质疏松大鼠骨髓基质细胞(O-r BMSCs),并以O-rBMSCs为种子细胞构建细胞膜片。通过倒置显微镜、HE染色、扫描电镜及透射电镜对细胞膜片进行形态学检测;以免疫组织化学染色检测细胞外基质相关蛋白的表达情况。结果成功建立了大鼠PMOP模型,体外分离培养的O-rBMSCs具有多向分化潜能。显微镜下可见细胞复层生长,采用富含维生素C的培养基连续培养10 d左右即可获得白色膜样结构,该细胞膜片具有较好的弹性,HE染色及扫描电镜观察发现O-rBMSCs膜片由多层细胞及丰富的细胞外基质组成。透射电镜下可观察到细胞间连接。免疫组织化学染色示O-rBMSCs膜片高表达Ⅰ型胶原、纤维连接蛋白。结论 O-rBMSCs体外采用富含维生素C的培养基连续培养可构建细胞膜片,该细胞膜片富含细胞外基质,有望应用于骨质疏松机体的组织再生。

脱钙骨基质支架构建组织工程骨的实验研究

目的 以同种异体骨脱钙骨基质(demineralizedbonematrix ,DBM )为支架材料,复合体外诱导培养的人骨髓间充质干细胞(humanmesenchymalstemcells ,hMSCs) ,构建组织工程骨并通过裸鼠皮下异位成骨实验及裸鼠皮下致瘤性实验验证其成骨效果及安全性。方法 贴壁法培养hMSCs ,体外诱导培养扩增,以1 85 7×10 6/ml的密度与DBM复合构建组织工程骨,体外培养,并在扫描电镜下观察细胞与材料复合情况,进行组织学观察。同时进行了裸鼠皮下异位成骨实验。结果 细胞与支架复合后3d ,细胞与DBM表面及孔隙可实现良好复合;复合后5d ,扫描电镜观察到细胞基质分泌旺盛,充满支架孔隙。裸鼠皮下成骨实验证明其成骨效果良好。结论 以本实验中使用的细胞培养方法扩增、诱导分化的种子细胞生物安全性好,自制的DBM具有良好的生物相容性,可为种子细胞生长提供较好的三维空间,按照标准化工艺流程制备的组织工程骨安全、有效。