SDF-1/CXCR4在大鼠肝卵圆细胞增殖过程中的表达及意义

目的研究基质细胞衍生因子-1（stromal cell-derived factor-1,SDF-1）及其受体CXCR4、CK18、CK19及AFP在大鼠肝卵圆细胞增殖过程中的表达情况,进一步探讨SDF-1/CXCR4生物学轴的作用。方法选择144只体重180～200g雄性Wistar大鼠,按随机抽签法平均分为4组后分别给予不同的处理,即灌喂2-乙酰氨基芴（2-acetylaminofluorene,AAF）和（或）尾静脉注射CXCR4的特异性抑制剂AMD3100,并联合行部分肝切除术（PH）,因而分别命名为AAF组、AAF/AMD3100组、AMD3100组和PH组。AAF剂量为15mg/（kg·d）,AMD3100剂量为1.25mg/（kg·d）。各组分别于手术后第3、5、7、10、14和21d各处死6只大鼠,取其肝组织行常规组织学观察,采用免疫组织化学染色法检测肝卵圆细胞中SDF-1及其受体CXCR4、CK18、CK19和AFP的表达。结果AAF组大鼠肝组织内见明显的肝卵圆细胞增殖反应且卵圆细胞胞浆CK18、CK19、AFP和SDF-1及其受体CXCR4染色均呈阳性;AAF/AMD3100组大鼠肝卵圆细胞增殖的数量和SDF-1及CXCR4阳性细胞数较AAF组明显减少（P〈0.05,P〈0.01）;AMD3100组及PH组大鼠肝组织均未见到卵圆细胞。结论肝卵圆细胞在增殖过程中表达CK18、CK19、AFP和SDF-1及其受体CXCR4,SDF-1/CXCR4轴可能有刺激肝卵圆细胞增殖的作用。     

大鼠肝卵圆细胞的电镜观察及SDF-1/CXCR4轴作用研究

目的 本研究通过应用AMD3100封闭卵圆细胞表面CXCR4受体,从而起到抑制趋化因子SDF-1的生物活性,观察大鼠肝卵圆细胞的生长及SDF-1,CXCR4 mRNA表达情况,探讨SDF-1/CXCR4轴在肝卵圆细胞激活、增殖、分化中所起的作用.方法 建立卵圆细胞增殖模型,分为四组,分别为:2-AAF/PH组,AMD3100/PH组,2-AAF/AMD3100/PH组,PH组,重(150±20)g的Wistar大鼠予2-AAF灌喂,联合2/3肝切除,制作卵圆细胞模型,并通过尾静脉注射AMD3100阻断SDF-1的生物学作用,分别在术后的第3、5、7、10、14、21天6个时间点各处死6只大鼠,取肝脏标本行CXCR4和SDF-1 RT-PCR,检测卵圆细胞CXCR4及SDF-1 mRNA的表达情况,并取第10天肝脏透射电镜检查,观察卵圆细胞的超微结构.结果 给予AMD3100抑制SDF-1作用后,肝脏卵圆细胞数量减少,细胞膜受体CXCR4表达下调,同时SDF-1表达也呈下调趋势.结论 抑制SDF-1活性可以在一定程度上减少卵圆细胞的增殖,SDF-1可以通过自分泌或旁分泌途径激活并促进肝卵圆细胞增殖.     

大鼠肝卵圆细胞的分离培养和体外分化研究

目的 观察大鼠肝卵圆细胞的活化，为进一步研究肝卵圆细胞特征建立简单的分离培养方法。方法 利用2-乙酰氨基笏／部分肝切除建立肝卵圆细胞活化的大鼠模型，采用选择性消化法从该模型中分离纯化肝卵圆细胞，并做免疫细胞荧光鉴定。用丁酸钠诱导其分化。结果 成功地建立了肝卵圆细胞活化模型，并从中分离培养了表达OV6、CK19、AFP、白蛋白、c-kit、Thy1、CD45和CD34的卵圆细胞。在丁酸钠刺激下它可向肝细胞分化。结论 利用选择性消化法可以分离到肝卵圆细胞，并且其具有肝干细胞的特征。     

SDF-1/CXCR4介导体外冲击波促进大鼠骨髓间充质干细胞的黏附、迁移作用

目的探讨体外冲击波(extracorporeal shock wave,ESW)对大鼠骨间充质干细胞(marrow mesenchymal stem cells,MSCs)黏附、迁移及成骨分化的影响及SDF-1/CXCR4通路在其中的作用。方法体外试验分四组:空白对照组(Ctrl组)、冲击波组(ESW组)及CXCR4特异性抑制剂AMD3100对照组(AMD组),采用最适宜能力ESW(500脉冲次数、10 kV)处理MSCs,通过黏附率、划痕试验、Transwell试验对比MSCs黏附及迁移能力的差别,通过ELISA检测SDF-1分泌表达及蛋白免疫印迹法检测CXCR4的表达,研究SDF-1/CXCR4通路的作用;体内试验则选取12周龄SD大鼠48只,随机分成Ctrl、ESW及AMD 3组各16只,采用右侧股骨中段骨缺损模型,各组骨缺损处植入载有该组细胞的PLGA支架,AMD组术后接受AMD3100注射(1 mg/kg/day),于术后第4、8周取材,通过HE染色评估骨缺损区域的骨愈合及新生骨形成情况。结果 ESW明显增加了MSCs的SDF-1分泌量及CXCR4受体表达,促进了MSCs的黏附、迁移及骨缺损的愈合,AMD3100可部分抑制ESW此促进作用。结论 ESW可促进MSCs的黏附、迁移能力,并促进骨缺损区域的骨愈合,其分子机制与分泌型蛋白SDF-1及其受体CXCR4的表达相关,此结果为ESW在促进骨愈合治疗中的临床应用提供了理论基础。     

大鼠肝卵圆细胞的分离培养及干细胞标志分析

目的研究简单易行的成体大鼠肝卵圆细胞的分离培养及干细胞鉴定方法。方法采用2-乙酰氨基芴/部分肝切除术刺激建立成体大鼠肝卵圆细胞增殖模型,于肝切除术后第12d切取剩余肝脏,使用胶原酶Ⅳ消化分离和Percoll梯度离心纯化肝卵圆细胞,免疫荧光技术和RT-PCR分析法检测肝卵圆细胞标志物mRNA表达。结果分离得到的肝卵圆细胞存活率达到90%,经c-kit免疫荧光显色,PCR分析显示有CK19和白蛋白mRNA表达。生长因子诱导下有向胆管细胞和肝细胞分化的特性。结论简单易行的肝卵圆细胞分离纯化及鉴定方法和肝卵圆细胞成功培养,为进一步研究肝干细胞生物学特性和与肝癌的关系提供了物质基础。     

ABCG2/Bcrpl基因在大鼠肝脏卵圆细胞中的表达

目的探讨ABCG2／Bcrp1基因在大鼠肝脏卵圆细胞中的表达及意义。方法建立大鼠2-乙酰氨基芴／三分之二肝切除模型，二步胶原酶灌注结合Percoll密度梯度离心分离大鼠肝脏卵圆细胞，采用荧光定量PCR技术检测ABCG2／Bcrp1基因在大鼠肝脏卵圆细胞和肝细胞中的表达水平，免疫组织化学、免疫荧光双标染色和Westernblot方法检测该转运蛋白的表达。结果大鼠肝卵圆细胞中ABCG2／Bcrp1基因的表达水平是肝细胞的13．8倍，ABCG2／Bcrp1蛋白相对分子质量大小为72000，定位于卵圆细胞膜。其表达位于门脉区周围，并向肝小叶延伸。免疫荧光双标染色显示与OV-6共表达。结论大鼠肝卵圆细胞表达高水平的ABCG2／Bcrp1，后者参与肝干细胞免受外源性化学物质损伤的自我保护机制。     

大鼠肝卵圆细胞增殖模型的建立和体外分离的实验研究△

目的探讨以2-乙酰氨基芴（2-AFF）灌胃与2／3肝切除法联合运用建立大鼠肝卵圆细胞增殖模型的适宜剂量,并探讨肝卵圆细胞的体外分离培养方法。方法将174只Wistar大鼠随机分为4个实验组（各30只）、未处理组（24只）和生理盐水组（30只）。4个实验组大鼠分别给予5、10、15及20mg／（kg·d）2-AAF灌胃（分别对应第1、2、3及4实验组）,于第5天行2／3肝切除,术后继续灌胃至处死大鼠;生理盐水组大鼠以生理盐水灌胃,其余操作同实验组;未处理组大鼠不做任何处理。6组分别于肝切除术后第4、8、12及16天各随机处死6只大鼠,取肝组织行HE染色和免疫组化染色,观察肝卯圆细胞的增殖情况[第4天时同时检测血清丙氨酸氨基转移酶（ALT）和天冬氨酸氨基转移酶（AsT）水平];并采用二步胶原酶灌注结合Percoll密度梯度离心法对大鼠肝卵圆细胞进行分离和培养。结果肝切除术后第4天,未处理组、生理盐水组、第1、2、3及4实验组大鼠的存活率分别为100％（24／24）、93％（28／30）、93％（28／30）、90％（27／30）、90％（27／30）及80％（24／30）。肝切除后第4天,与未处理组及生理盐水组比较,第2、3和4实验组大鼠的血清ALT及AST水平均升高（P〈0.05）。HE染色结果显示,第2、3及4实验组大鼠的肝组织均出现不同程度的肝损伤,其中第3和第4实验组均可见明显的肝卵圆细胞增殖反应;免疫组化染色结果显示,第2、3及4实验组卵圆细胞标志6（OV-6）表达阳性细胞数在术后第4、8、及12天,随2．AAF剂量的增加逐渐升高,与2-AAF间呈剂量嫩应关系（P〈0.05）。大鼠肝卵圆细胞进行体外分离和培养后,经OV-6免疫组化染色鉴定,有80％的细胞表达呈阳性。结论联合运用15mg／（kg·d）2-AFF灌胃加2／3肝切除,于术后第12天,有效诱导了肝卵圆细胞的增殖,且造模大鼠的耐受性较好、死亡率低。采用二步胶原酶灌注结合Percoll密度梯度离心法较成功地分离出了大鼠肝卵圆细胞。     

CXCR4抑制剂AMD3100抑制结肠癌细胞奥沙利铂耐药的机制研究

目的：探讨CXCR4抑制剂AMD3100对奥沙利铂耐药的影响及其作用机制。方法：构建奥沙利铂耐药细胞HCT116;q-PCR和Western blot检测耐药组与对照组CXCR4表达及PI3K-AKT信号通路磷酸化水平。q-PCR和Western blot检测CXCR4抑制剂AMD3100刺激上述细胞系后PI3K-AKT信号通路磷酸化水平变化。CCK8检测AMD3100抑制CXCR4或联合应用AKT抑制剂LY294002对奥沙利铂耐药细胞的耐药性影响。结果：不同浓度奥沙利铂刺激后,耐药组细胞活性无显著变化,而对照组细胞活性随奥沙利铂浓度增加而显著下降。q-PCR和Western blot检测发现耐药组细胞CXCR4表达和PI3K-AKT磷酸化水平显著上升（P<0.05）。给予CXCR4抑制剂AMD3100后,CXCR4表达和PI3K-AKT磷酸化水平显著下降（P<0.05）。结论：CXCR4通过激活PI3K-AKT信号通路在结肠癌奥沙利铂耐药中发挥作用。AMD3100能够增强耐药细胞对奥沙利铂的敏感性,可能成为对抗结肠癌化疗耐药的潜在治疗药物。     

Activin A suppressed hepatic oval cell-mediated liver regeneration in vivo

目的 研究Activin A对卵圆细胞介导肝再生的抑制作用及其机制.方法 建立2-乙酰胺基芴/部分肝切除卵圆细胞介导肝再生模型,肝切除后立即经门静脉注射1 μg Activin A(Activin A组),或生理盐水(对照组).肝切除后不同时间点取肝脏标本检测卵圆细胞增殖及肝再生率和磷酸化smad2,p15和p21的表达.结果 Activin A组肝脏中卵圆细胞的增殖及肝再生率均明显低于对照组；Activin A组肝脏中smad2的磷酸化水平及p15,p21的表达水平均高于对照组.结论 Activin A可以通过smad信号通路抑制卵圆细胞介导的肝再生.     

大鼠肝卵圆细胞中matrilin-2的表达及其意义

目的探讨大鼠肝脏再生过程中肝卵圆细胞matrilin-2的表达及其意义。方法利用大鼠部分肝切除(PH)或2-乙酰氨基芴灌胃+/部分肝切除(2-AAF/PH)建立大鼠肝脏再生模型,并设正常对照组。应用免疫组织化学和RT-PCR方法研究肝脏组织中matrilin-2表达情况。结果免疫组化发现正常对照组及PH组肝脏组织中只有极少量的matrilin-2表达位于胆管血管周围及肝窦状隙内,而在2-AAF/PH模型中可见matrilin-2表达位于门静脉周围的肝窦状隙内,RT-PCR发现2-AAF/PH组肝卵圆细胞中matrilin-2mRNA高表达,而PH组及正常对照组成熟肝细胞中无matrilin-2mRNA表达。结论matrilin-2是肝卵圆细胞在肝脏再生过程中产生的重要的细胞外基质蛋白,与肝卵圆细胞的增殖分化过程有密切关系。     

AMD3100抑制胰腺癌细胞增殖和侵袭的体外实验

目的 探讨CXCR4 特异性受体阻滞剂AMD3100 对胰腺癌细胞增殖和侵袭能力的影响及其可能的作用机制.方法 用CCK-8 检测经不同浓度AMD3100 处理后人胰腺癌细胞株SW1990 的增殖.Matrigel 胶铺设的transwell 小室检测经AMD3100 处理后SW1990 的侵袭能力.RT-PCR 法检...     

CXCR4 antagonist delivery on decellularized skin scaffold facilitates impaired wound healing in diabetic mice by increasing expression of SDF‐1 and enhancing migration of CXCR4‐positive cells

C‐X‐C chemokine receptor type 4 (CXCR4) is an alpha‐chemokine receptor specific for stromal cell‐derived factor 1 (SDF‐1 also called CXCL12). The antagonist of CXCR4 can mobilize CD34+ cells and hematopoietic stem cells from bone marrow within several hours, and it has an efficacy on diabetes ulcer through acting on the SDF‐1/CXCR4 axis. In this study, we investigated for the first time whether the antagonist of CXCR4 (Plerixafor/AMD3100) delivered on acellular dermal matrix (ADM) may accelerate diabetes‐impaired wound healing. ADM scaffolds were fabricated from nondiabetic mouse skin through decellularization processing and incorporated with AMD3100 to construct ADM‐AMD3100 scaffold. Full‐thickness cutaneous wound in streptozotocin (STZ)‐induced diabetic mice were treated with ADM, AMD3100, or ADM‐AMD3100. 21 days after treatment, wound closure in ADM‐AMD3100‐treated mice was more complete than ADM group and AMD3100 group, and it was accompanied by thicker collagen formation. Correspondingly, diabetic mice treated with ADM‐AMD3100 demonstrated prominent neovascularization (higher capillary density and vascular smooth muscle actin), which were accompanied by up‐regulated mRNA levels of SDF‐1 and enhanced migration of CXCR4 in the granulation tissue. Our results demonstrate that ADM scaffold provide perfect niche for loading AMD3100 and ADM‐AMD3100 is a promising method for diabetic wound healing mainly by increasing expression of SDF‐1 and enhancing migration of CXCR4‐positive cells.     

Attenuation of cartilage pathogenesis in post‐traumatic osteoarthritis (PTOA) in mice by blocking the stromal derived factor 1 receptor (CXCR4) with the specific inhibitor,AMD3100

SDF‐1 was found to infiltrate cartilage, decrease proteoglycan content, and increase MMP‐13 activity after joint trauma. In this study, we tested the hypothesis that interference of the SDF‐1/CXCR4 signaling pathway via AMD3100 can attenuate pathogenesis in a mouse model of PTOA. We also tested the predictive and confirmatory power of fluorescence molecular tomography (FMT) for cartilage assessment. AMD3100 was continuously delivered via mini‐osmotic pumps. The extent of cartilage damage after AMD3100 or PBS treatment was assessed by histological analysis 2 months after PTOA was induced by surgical destabilization of the medial meniscus (DMM). Biochemical markers of PTOA were assessed via immunohistochemistry and in vivo fluorescence molecular tomography (FMT). Regression analysis was used to validate the predictive power of FMT measurements. Safranin‐O staining revealed significant PTOA damage in the DMM/PBS mice, while the DMM/AMD3100 treated mice showed a significantly reduced response with minimal pathology. Immunohistochemistry showed that AMD3100 treatment markedly reduced typical PTOA marker expression in chondrocytes. FMT measurements showed decreased cathepsins and MMP activity in knee joints after treatment. The results demonstrate that AMD3100 treatment attenuates PTOA. AMD3100 may provide a viable and expedient option for PTOA therapy given the drug's FDA approval and well‐known safety profile. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1071–1078, 2015.     

离体冻伤模型创面愈合过程中基质细胞衍生因子1促表皮干细胞迁移的研究

目的 了解离体皮肤冻伤模型创面愈合过程中,基质细胞衍生因子1(SDF-1)对创缘表皮干细胞(ESC)的运动趋化作用.方法 体外构建三维皮肤等价物全层冻伤模型(创面呈孔形),免疫组织化学染色观察冻伤后3、7 d创缘间质内SDF-1的表达情况.另将冻伤模型分为对照组(创面区添加PBS 50 μL/孔)、SDF-1组(创面区添加100 ng/mL SDF-1,50μL/孔)和AMD3100组[创面区用100 ng/mL AMD3100(50μL/孔)处理30 min后,添加SDF-1 50μL/孔],观察各组创缘中ESC的分布变化.结果 免疫组织化学染色显示,冻伤后3、7 d创缘间质内SDF-1的表达逐渐增加.与对照组及AMD3100组相比,SDF-1组创缘基底层整合素β1阳性细胞数量增多,且部分阳性细胞向上层表皮迁移聚集,创缘ESC数量更多,表皮细胞层数增加.结论 SDF-1促进ESC向创缘迁移聚集参与创面修复,这可能是ESC参与创面修复过程的机制之一.     

大鼠2-乙酰胺基芴/部分肝切除模型中卵圆细胞增殖动力学的初步研究

目的 研究大鼠肝脏卵圆细胞增殖模型中卵圆细胞增殖率的变化,进一步了解卵圆细胞生物学特性.方法 采用2-乙酰胺基芴/部分肝切除(2-AAF/PH)的方法建立大鼠肝卵圆细胞增殖模型.免疫荧光双标技术检测肝切除术后不同时间点肝脏石蜡切片中卵圆细胞标志物上皮细胞黏附分子和增殖标志物增殖细胞核抗原的共表达情况,对阳性细胞进行定量计数分析;并采用荧光双标和天狼猩红染色观察此过程中肝星状细胞激活和肝脏胶原沉积的情况.结果 术后第2天门静脉区开始出现少量卵圆细胞,到第9天数量达到高峰,此后数量逐步下降.此过程中卵圆细胞的增殖率逐步下降,从第2天的(91.3±1.6)%下降到第12天的(53.6±4.4)%,差异有统计学意义(P＜0.01).激活的肝星状细胞一直伴随卵圆细胞增殖并向肝实质延伸,分泌的胶原形成细胞外基质包绕小管样结构的卵圆细胞.结论 2-AAF/PH模型中卵圆细胞数量达到高峰前,其增殖率已经开始逐渐下降.肝星状细胞可能通过分泌细胞外基质和多种因子严格调控卵圆细胞的增殖.     

基质细胞衍生因子联合外周血内皮祖细胞移植治疗裸鼠肢体缺血

目的 应用基质细胞衍生因子(SDF-1)结合外周血内皮祖细胞(EPCs)移植治疗裸鼠肢体缺血,探讨其促进血管新生的能力.方法 建立裸鼠后肢缺血模型,随机分为缺血对照组、EPCs移植组、SDF-1组、SDF-1联合EPCs移植组及SDF-1联合AMD3100处理后的EPCs移植组.移植第3、7天检测后肢腓肠肌CD34+VEGFR+细胞数,第28天检测缺血区新生血管密度.结果 移植第3天对照组、EPCs组、SDF-1组、SDF-1+EPCs组、SDF-1+AMD3100 EPCs组双阳性细胞数分别为0.00±0.00个/HP、5.30±0.65个/HP、0.00±0.00个/HP、10.31±0.63个/HP及1.86±0.17个/HP;第7天分别为0.00±0.00个/HP、7.05±0.18个/HP、0.00±0.00个/HP、11.81±0.53个/HP及2.83±0.48个/HP,第28天新生毛细血管数分别为3.00 ±0.13个/HP、6.15±0.04个/HP、6.20±0.10个/HP、10.65 ±0.08个/HP、6.21±0.08个/HP.SDF-1可增加缺血区CD34+ VEGFR+细胞浸润数量(P＜0.05),提高新生血管数量(P＜0.05),SDF-1联合外周血EPCs可进一步提高新生血管数量(P＜0.05).结论 SDF-1能够促进EPCs归巢,增强血管形成能力,促进血管新生;AMD3100能够阻断SDF-1的诱导迁移效应.

Abstract：

Objective To explore the effect of stromal cell-derived factor-1 ( SDF-1 ) in combination with transplantation of peripheral blood endothelial progenitor cells (EPCs) for the treatment of nude mice hindlimb ischemia. Methods Hindlimb ischemia model was established in nude mice, mice were then divided into five groups randomly: ischemic control group, peripheral blood EPCs transplantation group, SDF-1 local application group, SDF-1 combined with EPCs group, SDF-1 combined with AMD3100 treated EPCs group. Local CD34+VEGFR+ cells in the hind gastrocnemius were detected at day 3,7 after transplantation. The intensity of neovasculorization were evaluated at day 28. Results The double-positive cells number of control group, EPCs group, SDF-1 group, SDF-1 + EPCs group, SDF-1 + AMD3100 EPCs group were 0.00 ±0.00,5. 30 ±0.65,0.00 ±0.00,10. 31 ±0. 63,1. 86 ±0. 17 at day 3 and 0. 00 ±0. 00, 7.05 ±0. 18,0. 00 ±0. 00,11. 81 ±0. 53,2. 83 ±0. 48 at day 7. The number of new capillaries were 3. 00 ± 0.13,6.15 ± 0. 04,6. 20 ± 0. 10,10. 65 ± 0.08,6. 21 ±0. 08 at day 28. SDF-1 increased the CD34 + VEGFR+ cells (P ＜0. 05) and the number of new vessels (P ＜0.05). SDF-1 combined EPCs further increased the number of new vessels (P ＜ 0. 05 ). Conclusions SDF-1 enhances blood vessel formation and promotes angiogenesis by promoting EPCs homing, which could be blocked by AMD3100.     

血管内皮干细胞动员剂对糖尿病小鼠颅骨缺损愈合的影响

目的 探讨血管内皮干细胞(endothelial pregenitor cell,EPC)动员剂AMD3100对糖尿病小鼠颅骨缺损愈合的影响.方法 2型糖尿病小鼠55只,随机分为未手术组(n=5)、实验组(n=25)和对照组(n=25).实验组和对照组均在其颅骨表面制造2个直径3 mm圆形骨缺损,实验组于术后第3天起给予AMD3100腹腔注射,每日10 mg/kg,共15d,对照组给予生理盐水腹腔注射.未手术组处死5只小鼠,实验组和对照组分别于术后1、2、4、8、12周时处死5只小鼠,取外周血测量术前及术后7、14 d小鼠血液EPC含量;取颅骨标本,对术后第4、8、12周标本行micro-CT检查,测量计算骨缺损愈合百分比;对所有标本的脱钙石蜡切片进行HE染色,对术后第1、2、4周标本的冰冻切片行CD31和骨钙素免疫荧光染色,计算成骨区血管密度和成骨细胞密度.采用t检验对数据进行统计学分析.结果 糖尿病小鼠EPC的动员在创伤后1周基本消失,而AMD3100可显著增高创伤后期血液中EPC水平.AMD3100治疗的糖尿病小鼠在术后第8周和第12周时其骨缺损愈合百分比分别为50.5％、50.9％,均高于对照组的34.8％、40.2％,差异具有统计学意义(P＜0.05);实验组成骨区血管密度和成骨细胞密度在术后1、2、4周均较对照组增加2倍左右,以术后第2周最显著(实验组毛细血管密度2.47％,成骨细胞密度1.22％;对照组分别是6.11％、2.81％).结论 AMD3100可通过增加成骨区血管密度和成骨细胞密度而改善糖尿病小鼠颅骨缺损愈合程度.     

AMD3100体外阻断基质细胞衍生因子1/趋化因子受体4信号通路对人关节软骨细胞分泌基质金属蛋白酶3、9、13水平的影响

目的探讨趋化因子受体4(chemokine receptor 4,CXCR4)特异性拮抗剂AMD3100体外阻断基质细胞衍生因子1(stromal cell derived factor 1,SDF-1)/CXCR4信号通路对人关节软骨细胞分泌基质金属蛋白酶(matrixmetalloproteinase,MMP)3、9、13水平的影响,明确AMD3100的作用机制。方法取12例骨关节炎(osteoarthritis,OA)患者144块软骨组织(OA软骨组)和12例创伤性截肢患者144块正常软骨组织(正常软骨组)(Mankin评分均为0或1),根据添加培养液不同,每组再分为A、B、C 3个亚组。A亚组含1 000 nmol/L AMD3100及100 ng/mL SDF-1的DMEM液,B亚组含1 000 nmol/L MAB310及100 ng/mL SDF-1的DMEM液,C亚组含100 ng/mL SDF-1的DMEM液。体外培养2、4 d后,ELISA法测定培养液内MMP-3、9、13含量,RT-PCR检测软骨组织中MMP-3、9、13 mRNA表达。结果 ELISA法及RT-PCR检测示:同组相同时间点A亚组MMP-3、9、13含量及mRNA表达均显著低于B、C亚组(P<0.05)。同一时间点相同亚组OA软骨组MMP-3、9、13含量及mRNA表达均显著高于正常软骨组(P<0.05)。结论 SDF-1通过SDF-1/CXCR4信号通路可诱导人关节软骨中MMP-3、9、13的表达和释放;AMD3100可阻断SDF-1/CXCR4信号通路,使软骨细胞MMP-3、9、13 mRNA表达水平及分泌量降低,但AMD3100不能使退变的OA软骨分泌MMP-3、9、13恢复至正常软骨水平。     

Mobilization of bone marrow mesenchymal stem cells in vivo augments bone healing in a mouse model of segmental bone defect

Although the number of mesenchymal stem cells (MSC) in the bone marrow is sufficient to maintain skeletal homeostasis, in osteopenic pathology, aggravated osteoclast activity or insufficient osteoblast numbers ensue, affecting normal bone remodeling. Most of the currently available therapies are anti-resorptive with limited osteogenic potential. Since mobilization of stem/progenitors from the BM is a prerequisite for their participation in tissue repair, amplification of endogenous stem cells may provide an alternative approach in these conditions. The present study determined the potential of MSC mobilization in vivo, using combinations of different growth factors with the CXCR4 antagonist, AMD3100, in a mouse model of segmental bone defect. Results indicated that among several factors tested IGF1 had maximum proliferative ability of MSC in vitro. Results of the in vivo studies indicated that the combination of IGF1 and AMD3100 provided significant augmentation of bone growth as determined by DXA, micro-CT and histomorphometry in mice bearing segmental fractures. Further, characterization of MSC isolated from mice treated with IGF1 and AMD3100 indicated Akt/PI3K, MEK1/2-Erk1/2 and smad2/3 as key signaling pathways mediating this effect. These data indicate the potential of in vivo stem cell mobilization as a novel alternative for bone healing.     

Long‐term administration of AMD3100, an antagonist of SDF‐1/CXCR4 signaling,alters fracture repair

Fracture healing involves rapid stem and progenitor cell migration, homing, and differentiation. SDF‐1 (CXCL12) is considered a master regulator of CXCR4‐positive stem and progenitor cell trafficking to sites of ischemic (hypoxic) injury and regulates their subsequent differentiation into mature reparative cells. In this study, we investigated the role of SDF‐1/CXCR4 signaling in fracture healing where vascular disruption results in hypoxia and SDF‐1 expression. Mice were injected with AMD3100, a CXCR4 antagonist, or vehicle twice daily until euthanasia with the intent to impair stem cell homing to the fracture site and/or their differentiation. Fracture healing was evaluated using micro‐computed tomography, histology, quantitative PCR, and mechanical testing. AMD3100 administration resulted in a significantly reduced hyaline cartilage volume (day 14), callus volume (day 42) and mineralized bone volume (day 42) and reduced expression of genes associated with endochondral ossification including collagen Type 1 alpha 1, collagen Type 2 alpha 1, vascular endothelial growth factor, Annexin A5, nitric oxide synthase 2, and mechanistic target of rapamycin. Our data suggest that the SDF‐1/CXCR4 signaling plays a central role in bone healing possibly by regulating the recruitment and/or differentiation of stem and progenitor cells. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1853–1859, 2012