中枢神经损伤对大鼠股骨骨折愈合影响观察

摘要：[目的] 观察中枢神经损伤后大鼠股骨骨折愈合速度和骨痂量的变化，分析中枢神经损伤对大鼠股骨骨折愈合速度影响的机制。[方法] 54只雄性Wistar大鼠随机分成3组，（1）脑外伤合并股骨骨折组18只；（2）脊髓损伤合并股骨骨折18只；（3）单纯股骨骨折18只。术后7、14、28d分批处死动物，大体体积测量骨痂，X线片评分，并做HE染色比较。[结果] 脑外伤组，脊髓损伤组形成骨痂体积、X线片评分高于单纯股骨骨折组，差异有显著性（P〈0．05）。HE染色结果显示脑外伤组、脊髓损伤组骨折愈合速度较单纯骨折组加快。[结论] 中枢神经损伤后大鼠骨折愈合加速，骨痂量增多，中枢神经损伤后引起骨痂量和骨折愈合速度的改变，表明中枢神经损伤对骨折愈合有促进作用。     

中枢神经损伤大鼠骨痂中神经肽的表达

[目的]研究中枢神经损伤后大鼠股骨骨折骨痂中神经肽的表达。[方法]45只雄性Wistar大鼠随机分成3组，脑外伤合并股骨骨折组15只，脊髓损伤合并股骨骨折15只，单纯股骨骨折15只。术后4、7、14、21、28d分批处死动物，行神经肽免疫组织化学染色。[结果]脑外伤组，脊髓损伤组免疫组化染色结果显示骨折愈合过程中骨痂骨膜内、外层骨祖细胞、软骨细胞、成骨细胞内CGRP、SP阳性表达，与单纯骨折组相比，差异具有显著性。[结论]中枢神经损伤大鼠骨痂中神经肽有显著性改变，推测神经因素参与调节骨折愈合过程。     

戊酸雌二醇对去势大鼠骨折愈合影响的实验研究

目的 探讨戊酸雌二醇在骨质疏松性骨折愈合过程中的作用,为绝经后骨质疏松性骨折的治疗提供理论依据.方法 选用6月龄雌性Sprague-Dawley(SD)大鼠54只,实验分为SHAM组(假手术组)、OVX组(去势组)、补佳乐组.除SHAM组外,其余各组均切除双侧卵巢建立骨质疏松动物模型.去势后8周各组行右股骨骨折建立骨折模型,同时补佳乐组按0.104(mg·kg-1·d-1)灌胃.3组均在骨折后第2、4、6、8周处死大鼠后行放射学观察骨痂变化,骨痂HE染色及成骨细胞、破骨细胞计数.结果 ①放射学:OVX组骨痂密度影低,8周时OVX组骨折线仍然存在,SHAM组和补佳乐组骨折线模糊甚至消失.②骨痂组织学:OVX组骨小梁表面破骨细胞明显增多,成骨细胞也较多,呈骨高转换状态.8周时骨小梁变细、中断,软骨成分仍较多,软骨性骨痂向骨性骨痂转化缓慢;SHAM组和补佳乐组随骨折愈合骨小梁逐渐增加成熟,小梁骨粗大,排列紧密,骨小梁表面成骨细胞体积大,胞浆丰富,破骨细胞减少.③成骨、破骨细胞指数:2、4周OVX组破骨细胞指数大于补佳乐组和SHAM组.成骨细胞指数在3组间差异无显著性.结论 戊酸雌二醇对于促进绝经后骨质疏松性骨折早期愈合有效.     

护骨素及配体在卵巢切除大鼠骨组织的蛋白表达和细胞定位

目的对卵巢切除和假切大鼠骨组织中护骨素（OPG）和配体（RANKL）的表达进行比较，观察不同分化阶段成骨细胞的OPG和RANKL表达变化，深入地探讨成骨细胞对破骨细胞发生的调控作用。方法9月龄雌性大鼠分为卵巢切除组和假切组，相同条件喂养3月后处死，取材制作骨病理切片，用免疫组织化学方法测定大鼠股骨OPG和RANKL的蛋白表达，用图像分析软件对蛋白表达情况半定量分析，对各组数据和组织形态进行分析比较。结果OPG和RANKL蛋白在骨组织表达相对稳定。RANKL主要表达在增殖活跃的成骨细胞和幼稚的骨细胞，OPG主要表达在成熟骨细胞和静息骨衬里细胞。与假切组相比，卵巢切除组骨组织内RANKL表达升高（P〈0．01），OPG表达降低（P〈0．05）。结论卵巢切除后骨组织中RANKL/OPG升高，破骨细胞活性增强，骨转换加快。不同发育阶段的成骨细胞对破骨细胞有不同的调节作用，幼稚阶段表现出对破骨细胞的诱导作用，而成熟阶段则表现为抑制作用。     

合并脑外伤的骨折愈合过程中PDGF的作用

目的 通过研究大鼠股骨干骨折合并脑外伤时骨痂组织内PDGF表达水平的变化,探讨脑外伤对骨折愈合的影响及作用机制. 方法 取12周雄性SD大鼠64只,体重(356 4±25)g,随机分成8组,每组8只.A1、B1、Cl、D1组分别为骨折合并脑外伤1、2、3、4周组,制作脑外伤和股骨干骨折模型;A2、B2、C2、D2组分别为单纯骨折1、2、3、4周组,制作单纯股骨干骨折模型作对照.各组摄CR片后截取骨痂,行HE染色观察骨痂生长情况及其组织形态,免疫组织化学染色测定PDGF表达,原位杂交检测PDGF mRNA表达. 结果 CR片示在同一时间点A1、B1、C1、D1组较A2、B2、C2、D2组骨折端骨痂形成早,骨痂多,骨折愈合快.HE染色示A1组可见较多早期软骨细胞、成纤维细胞,A2组骨折间隙可见成纤维细胞,仅夹杂有少量的早期软骨细胞;B1组骨折端有新生骨小梁长入,B2组未见骨小梁形成;C1组骨折端有大量编织骨形成且骨小粱间有少量成熟软骨细胞,C2组少量骨小梁向骨折端长入;D1组编织骨向板层骨转化,D2组骨折端为不成熟骨小梁.免疫组织化学染色和原位杂交实验均可见成纤维细胞、间充质细胞、血管内皮细胞、早期软骨细胞、成骨细胞、破骨细胞胞浆出现广泛的强阳性反应,A1、B1、C1、D1组PDGF和PDGF mRNA阳性细胞百分数均高于同一时间点A2、B2、C2、D2组,差异有统计学意义(P<0.05). 结论 脑外伤对骨折愈合有促进作用,可能与脑外伤后PDGF表达水平升高有关.     

骨碎补经骨髓间充质干细胞调节OPG/RANKL/RANK通路抑制破骨细胞的实验研究

目的研究骨碎补作用绝经后骨质疏松大鼠骨髓间充质干细胞(bone marrow stromal cells,BMSCs)调节OPG/RANKL/RANK通路及对破骨细胞分化成熟的影响并探讨其可能的作用机制。方法实验大鼠去双侧卵巢造模,分为实验组(OVXDF,造模+骨碎补水煎液灌胃)、模型组(OVX,造模+0.9%生理盐水灌胃)、假手术组(SHAM,假手术+0.9%生理盐水灌胃),造模成功后提取BMSCs,将BMSCs和骨髓单核细胞共培养于Transwell小室的上室和下室,分为实验组+破骨细胞(OVXDF+OC)、模型组+破骨细胞(OVX+OC)、假手术组+破骨细胞(SHAM+OC)。下室加入破骨细胞诱导剂,倒置相差显微镜观察破骨细胞的分化成熟情况并计数,酶联免疫吸附剂测定(ELISA)检测下室培养液中骨保护素(osteoprotegerin,OPG)、RANKL的含量,实时荧光定量PCR和蛋白质印迹法(Western blot)检测BMSCs中Wnt10b、β-catenin、RANKL、OPG mRAN及蛋白表达并计算RANKL/OPG。结果在共培养系统中,与去卵巢灌胃大鼠BMSCs共培养的破骨细胞(OVXDF+OC)数量较单纯模型组+破骨细胞(OVX+OC)明显减少(P0.05)。下室培养液OPG含量及共培养BMSCs中Wnt10b、β-catenin、OPG mRAN及蛋白表达模型组+破骨细胞(OVX+OC)最低,RANKL及RANKL/OPG最高,经骨碎补灌胃后(OVXDF+OC)培养液中OPG含量及BMSCs细胞中Wnt10b、β-catenin、OPG mRAN及蛋白表达明显升高,培养液及BMSCs细胞中RANKL及RANKL/OPG明显降低(P0.05)。结论骨碎补可调节BMSCs细胞OPG、RANKL的表达,激活OPG/RANKL/RANK信号通路抑制破骨细胞的分化和成熟,此作用可能与BMSCs的Wnt/β-catenin信号通路的激活有关。     

骨碎补通过骨髓间充质干细胞调节RANKL/OPG抑制破骨细胞的实验研究

目的　研究骨碎补对绝经后骨质疏松大鼠骨髓间充质干细胞(bone marrow stromal cells,BMSCs)RANKL/OPG及破骨细胞分化成熟的影响并探查其可能的作用机制。方法 实验大鼠去双侧卵巢造模,分为实验组（OVXDF,造模+骨碎补水煎液灌胃）、模型组（OVX,造模+0.9%生理盐水灌胃）、假手术组（SHAM,假手术+0.9%生理盐水灌胃）,造模成功后提取BMSCs,将BMSCs和骨髓单核细胞共培养于Transwell小室的上室和下室,分为实验组+破骨细胞（OVXDF+OC）、模型组+破骨细胞（OVX+OC）、假手术组+破骨细胞（SHAM+OC）。下室加入破骨细胞诱导剂,倒置相差显微镜观察破骨细胞的分化成熟情况并计数,酶联免疫吸附剂测定（ELISA）检测下室培养液中骨保护素(osteoprotegerin,OPG)、RANKL的含量,并计算RANKL/OPG,实时荧光定量PCR和蛋白质印迹法(Western blot)检测BMSCs中Wnt10b、β-catenin、RANKL、OPG mRAN及蛋白表达并计算RANKL/OPG。结果 在共培养系统中,与去卵巢灌胃大鼠BMSCs共培养的破骨细胞（OVXDF+OC）数量较单纯模型组+破骨细胞（OVX+OC）明显减少（P＜0.05）。下室培养液OPG含量及共培养BMSCs中Wnt10b、β-catenin、OPG mRAN及蛋白表达模型组+破骨细胞（OVX+OC）最低,RANKL及RANKL/OPG最高,经骨碎补灌胃后（OVXDF+OC）培养液中OPG含量及BMSCs细胞中Wnt10b、β-catenin、OPG mRAN及蛋白表达明显升高,培养液及BMSCs细胞中RANKL及RANKL/OPG明显降低（P＜0.05）。结论 骨碎补可调节BMSCs细胞OPG、RANKL的表达,激活OPG/RANKL/RANK信号通路抑制破骨细胞的分化和成熟,此作用可能与BMSCs的Wnt/β-catenin信号通路的激活有关。     

失神经支配在大鼠骨折愈合过程中降钙素基因相关肽对骨保护素/破骨细胞分化因子影响的实验研究

目的 通过建立选择性切断大鼠感觉/运动神经联合胫骨骨折的动物模型,研究感觉/运动神经损伤后对骨折愈合的影响,并检测骨折愈合过程中降钙素基因相关肽(calcitonin gene related peptide,CGRP)对骨保护素(osteoprotegerin,OPG)/破骨细胞分化因子(receptor activator nuclear factor kappa B ligand,RANKL)体系的影响,初步探讨周围神经调节骨折愈合的机制.方法 取60只Wistar大鼠随机分为3组:前根(运动神经)切断+胫骨骨折组(anterior rhizotomy group,ART组);后根(感觉神经)切断+胫骨骨折组(posterior rhizotomy group,PRT组);单纯胫骨骨折组(sham operated group,SO组).分别于骨折术后7、14、21、28d处死大鼠,在骨折处上、下5mm部位取骨痂标本.免疫组织化学检测CGRP、OPG、RANKL的表达;采用软件Image-proplus 6.0进行图片分析;采用SPSS16.0进行统计学分析.结果 CGRP在SO组各时间点均呈强阳性表达,术后14 d和21 d,SO组、ART组和PRT组比较差异均有统计学意义(P＜0.05).OPG在SO组术后7d呈强阳性表达,以后逐渐下降但保持较高水平;术后14 d,PRT组和SO组、ART组比较差异有统计学意义(P＜0.05);术后21 d,SO组和PRT组、ART组比较差异有统计学意义(P＜0.05).RANKL在SO组21 d为表达高峰,以后逐渐下降;术后14 d,PRT组和ART组、SO组比较差异有统计学意义(P＜0.05);术后21 d,SO组和ART组、PRT组比较差异有统计学意义(P＜0.05).结论 在骨折愈合过程中,感觉神经纤维对骨折愈合的影响较运动神经纤维显著.CGRP能够调节OPG/RANKL的表达量的比值,从而影响骨折的愈合过程.失神经支配(尤其是感觉神经)导致CGRP对OPG/RANKL表达的调节作用降低,这不利于骨折的愈合.完整的神经支配是正常骨折愈合的必要条件之一.     

唑来膦酸联合胰岛素促进2型糖尿病并发雌激素缺乏大鼠骨折早期愈合

目的探讨唑来膦酸联合胰岛素对于2型糖尿病并发雌激素缺乏大鼠早期骨折愈合的影响。方法 32只雌性SD大鼠随机分为CF、DOF、DOFI和DOFIZ 4组。除CF组外,其余3组建立2型糖尿病并发雌激素缺乏动物模型,其中DOFI组和DOFIZ组分别给予单独胰岛素或联合唑来膦酸治疗,骨折后3周取材。通过对骨痂X线片、Micro-CT、番红O-固绿染色、TRAP阳性破骨细胞密度、OCN和Caspase-3的表达进行分析,评价单独应用胰岛素或联合唑来膦酸对其早期骨折愈合的影响。结果DOF组骨痂的骨折愈合X线评分、Tb.N、BV/TV、骨性骨痂面积比和OCN表达均显著低于CF组(P0.05),Th.Sp、TRAP阳性破骨细胞密度和Caspase-3表达均显著高于CF组(P0.05)。胰岛素干预后,DOFI组以上各受损指标中除了Th.Sp外均得到显著改善(P0.05)。联合唑来膦酸干预后,DOFIZ组骨痂面积、Tb.N、BV/TV和骨性骨痂面积比显著高于DOFI组(P0.05),Th.Sp和TRAP阳性破骨细胞密度显著低于DOFI组(P0.05)。结论胰岛素联合早期单剂量唑来膦酸干预可促进2型糖尿病并发雌激素缺乏大鼠骨折早期愈合。     

骨折合并颅脑损伤大鼠血小板衍生生长因子表达的研究北大核心CSCD

目的观察胫骨骨折合并颅脑损伤大鼠血清及骨痂组织内血小板衍生生长因子（PDGF）的表达变化,探讨颅脑损伤对骨折愈合的影响及作用机制。方法选择144只SD大鼠随机分为4组（n=36只）：正常对照组（N组）、颅脑损伤组（TBI组）、单纯骨折组（F组）和骨折合并颅脑损伤组（TBI＋F组）,并制作相应组别的损伤模型。造模后第3天、1周、2周、3周、4周处死大鼠,4组均采用酶联免疫吸附试验法检测大鼠血清PDGF的表达;F组和TBI＋F组大鼠通过x线片观察右胫骨骨折处骨痂生长情况,通过苏木精．伊红染色观察骨痂生长及组织形态,免疫组织化学法检测骨痂组织PDGF的表达,逆转录聚合酶链反应法检测骨痂组织PDGFmRNA的水平,并进行比较。结果x线片示TBI＋F组大鼠骨折愈合速度比F组快。TBI＋F组大鼠血清PDGF表达量较其他3组高,且峰值时间提前,差异均有统计学意义（P〈0．05）。TBI＋F组大鼠骨折端局部成骨活动较F组强。TBI＋F组大鼠第3天、1周时局部骨痂组织中PDGF阳性细胞数较F组明显增多升高,且峰值时间提前,差异均有统计学意义（P〈0．05）。TBI＋F组大鼠第3天、1周时局部骨痂组织中PDGFmRNA表达水平较F组显著增高,差异均有统计学意义（P〈0．05）。结论颅脑损伤可以加速大鼠骨折愈合的进程,这可能与颅脑损伤后大鼠体内PDGF的表达增高有关。     

骨髓间充质干细胞对糖尿病周围神经病变大鼠骨组织OGP/RANKL表达的影响

目的检测骨髓间充质干细胞局部注射后糖尿病周围神经病变大鼠骨组织OPG/RANKL的表达水平。方法 8周龄SPF级雄性自发性2型糖尿病GK大鼠30只,高脂饲料喂养造模。造模成功后(随机血糖≥11.1 mmol/L)暴露大鼠左侧股骨,人为造成开放性骨折并给予克氏针复位内固定,将培养收集浓缩的骨髓间充质干细胞注射于骨折周围肌肉软组织,于实验后第12周、16周、20周分别取材用免疫组化、western blot测定骨质OPG、RANKL的表达。结果实验组大鼠术后第12周、16周、20周骨组织免疫组化和western blot测定OPG表达明显较对照组增高,而RANKL的表达结果正好相反。结论骨髓间充质干细胞局部移植可以促进GK糖尿病大鼠骨折后骨组织中OPG的高表达,抑制RANKL表达,从而促进糖尿病大鼠骨折后骨质的愈合。     

脑损伤大鼠胫骨骨痂中降钙素基因相关肽的改变

目的研究脑损伤后大鼠胫骨骨痂中降钙素基因相关肽（CGRP）的变化及骨痂量的改变。方法将100只雄性Wistar大鼠随机分为两组,脑损伤加右胫骨骨折组和单纯右胫骨骨折组各50只。术后3、7、14、21、28 d分批处死,检查血清碱性磷酸酶,摄右胫骨X线片测量骨痂面积,骨痂行苏木精2伊红（HE）染色和降钙素基因相关肽免疫组织化学染色。结果脑损伤加骨折组较单纯骨折组术后3、7 d,碱性磷酸酶均显著升高（P〈0.01）;脑损伤加骨折组较单纯骨折组术后14、21 d,骨痂X线面积大;脑损伤组早期形成大量纤维骨痂和软骨骨痂,骨痂中降钙素基因相关肽免疫阳性神经纤维多,明显增厚的骨膜内层骨祖细胞、幼稚的软骨细胞胞浆内降钙素基因相关肽强阳性表达;骨折愈合快,降钙素基因相关肽表达明显增强。结论脑损伤后骨痂中降钙素基因相关肽有显著改变,并引起骨痂量和质的改变,推测降钙素基因相关肽参与调节骨折愈合过程。     

Bone fracture and bone fracture repair

Fracture healing is a multistage repair process that involves complex, well-orchestrated steps initiated in response to tissue injury. The early upregulation of IL-6, osteoprotegerin (OPG), VEGF, and BMPs indicates a central role for these factors in the initiation of cartilage and periosteal woven bone formation. In both callus fracture repair and stress fracture repair, the RANKL/OPG ratio is initially reduced, but peaks earlier in stress fracture healing than callus fracture healing. Though the understanding of the biological processes and molecular signals that coordinate fracture repair has advanced, the cause of variability observed in fracture repair is poorly understood.     

Expression of osteoprotegerin, receptor activator of NF-kappaB ligand (osteoprotegerin ligand) and related proinflammatory cytokines during fracture healing.

Fracture healing is a unique biological process regulated by a complex array of signaling molecules and proinflammatory cytokines. Recent evidence for the role of tumor necrosis family members in the coupling of cellular functions during skeletal homeostasis suggests that they also may be involved in the regulation of skeletal repair. The expression of a number of cytokines and receptors that are of functional importance to bone remodeling (osteoprotegerin [OPG], macrophage colony-stimulating factor [M-CSF], and osteoprotegerin ligand [receptor activator of NF-kappaB ligand (RANKL)]), as well as inflammation (tumor necrosis factor alpha [TNF-alpha] and its receptors, and interleukin-1alpha [IL-1alpha] and -beta and their receptors) were analyzed over a 28-day period after the generation of simple transverse fractures in mouse tibias. OPG was expressed constitutively in unfractured bones and elevated levels of expression were detected throughout the repair process. It showed two distinct peaks of expression: the first occurring within 24 h after fracture and the second at the time of peak cartilage formation on day 7. In contrast, the expression of RANKL was nearly undetectable in unfractured bones but strongly induced throughout the period of fracture healing. The peak in expression of RANKL did not correlate with that of OPG, because maximal levels of expression were seen on day 3 and day 14, when OPG levels were decreasing. M-CSF expression followed the temporal profile of RANKL but was expressed at relatively high basal levels in unfractured bones. TNF-alpha, lymphotoxin-beta (LT-beta), IL-1alpha, and IL-1beta showed peaks in expression within the first 24 h after fracture, depressed levels during the period of cartilage formation, and increased levels of expression on day 21 and day 28 when bone remodeling was initiated. Both TNF-alpha receptors (p55 and p75) and the IL-1RII receptor showed identical patterns of expression to their ligands, while the IL-1R1 was expressed only during the initial period of inflammation on day 1 and day 3 postfracture. Both TNF-alpha and IL-1alpha expression were localized primarily in macrophages and inflammatory cells during the early periods of inflammation and seen in mesenchymal and osteoblastic cells later during healing. TNF-alpha expression also was detected at very high levels in hypertrophic chondrocytes. These data imply that the expression profiles for OPG, RANKL, and M-CSF are tightly coupled during fracture healing and involved in the regulation of both endochondral resorption and bone remodeling. TNF-alpha and IL-1 are expressed at both very early and late phases in the repair process, which suggests that these cytokines are important in the initiation of the repair process and play important functional roles in intramembraneous bone formation and trabecular bone remodeling.     

骨松安激活Runx 2/Osterix途径促进骨质疏松性骨折愈合的机制研究

目的初步探索骨松安促进骨质疏松性骨折愈合的机制。方法建立骨质疏松性骨折大鼠模型,采用骨松安进行治疗,分别于7、14、21 d取出骨折端骨痂,通过HE染色观察骨痂生长情况,采用免疫组化、RT-qPCR检测Runx 2、Osterix的表达。结果 HE染色结果显示,骨松安治疗可在早期促进骨质疏松性骨折大鼠骨折端软骨细胞增生、成骨细胞成熟分化及编织骨形成。免疫组化、RT-qPCR结果显示,骨质疏松性骨折组大鼠Runx 2与Osterix的表达一直处于较低水平,在骨松安持续治疗下,Runx 2与Osterix的表达得到明显改善。结论骨松安可激活Runx 2/Osterix途径,加速前成骨细胞向成骨细胞分化,促进骨质疏松性骨折大鼠的骨折愈合。     

脊髓损伤大鼠胫骨骨痂中降钙素基因相关肽的改变

目的 研究脊髓损伤后大鼠胫骨骨痂中降钙素基因相关肽（ＣＧＲＰ）的变化及骨痂量的改变。方法 将１００只雌性Ｗｉｓｔａｒ大鼠随机分为２组,Ｔ１０－１１脊髓横断＋右胫骨骨折组和单纯右胫骨骨折组各５０只。术后３、７、１４、２１、２８ｄ分批处死,检查血清碱性磷酸酶（ＡＬＰ）,摄右胫骨Ｘ线片行骨痂评分,骨痂行苏木精－伊红（ＨＥ）染色和ＣＧＲＰ免疫组织化学染色。结果 脊髓缶伤组３、７ｄ,ＡＬＰ均显著升高（Ｐ〈０     

Programmed removal of chondrocytes during endochondral fracture healing

This investigation tested the hypothesis that the removal of chondrocytes during endochondral fracture healing involves an ordered process of programmed cell death. To accomplish this, unilateral closed fractures were created in the femora of 36 Sprague-Dawley rats. The rats were killed in groups of four on days 1, 3, 7, 14, 21, 28, 42, 49, and 56 after fracture. The femora were embedded in paraffin and tested for expression of specific markers of fragmented DNA with use of a terminal deoxyuridyl transferase-mediated deoxyuridine triphosphatebiotin nick end labeling (TUNEL) technique. To determine the potential for trans–differentiation of chondrocytes to osteoblasts calluses were also hybridized to detect expression of osteocal in mRNA. Cell proliferation was assessed by an immunohistochemical detection method for proliferating cell nuclear antigen. A separate group of four rats was killed on day 28 to represent the later stage of the endochondral ossification, and the calluses were examined for cellular morphology with transmission electron microscopy. The results showed a coordination in both time and space of the activities of cellular proliferation and programmed cell death. Cell proliferation was most active in the earlier phases of fracture healing (days 1 through 14) although TUNEL expression was apparent in hypertrophic chondrocytes on day 14 after fracture and persisted until day 28. In the later stages of fracture healing (days 14 through 28), proliferating cell nuclear antigen was no longer synthesized in hard callus (intramembranous bone) and cell removal was the dominant activity in soft callus chondrocytes. Expression of osteocalcin mRNA was detected in osteoblasts but not in hypertrophic chondrocytes or in any other nonosteoblastic cell type. These findings support the hypothesis that the removal of chondrocytes during endochondral fracture healing is part of an ordered transition of tissue types in which the cellular mechanisms are genetically programmed to involve proliferation, maturation, and apoptotic cell death.     

鞘注神经生长因子促进大鼠胫骨骨折愈合的实验研究

目的 研究鞘注神经生长因子(NGF)对大鼠胫骨骨折愈合的影响,以及相应脊髓背根神经节(DRG)与胫骨骨痂中的降钙素基因相关肽、P物质的表达变化. 方法 成年雄性SD大鼠48只随机分为两组.实验组予NGF 1μg/d连续鞘注14 d,对照组予等量生理盐水.术后7、14、21、28 d分批处死动物,行骨痂X线评分、骨痂/骨干比值测量.免疫组织化学法测定相应节段DRG与胫骨骨痂中的CGRP、SP表达.结果 术后21 d,NGF组X线评分低于对照组,21 d、28 d骨痂/骨干比值低于对照组.HE染色显示各时期NGF组软骨内成骨过程增强,骨痂成熟度高于对照组,骨痂改建过程提前且更为完全.CGRP、SP在DRG及胫骨骨痂中表达的平均光密度(OD)值高于同期对照组,差异有统计学意义(P＜0.05).相关性分析显示DRG神经肽表达OD值与骨痂OD值明显正相关. 结论 鞘注神经生长因子可促进DRG与骨折骨痂中的神经肽表达,促进成骨细胞增殖与软骨内骨化,减小骨痂体积并加速骨折的愈合及塑形改建过程.推测神经生长因子与DRG神经肽参与了中枢神经调控外周成骨活动的过程.     

Low‐magnitude high‐frequency vibration enhances gene expression related to callus formation,mineralization and remodeling during osteoporotic fracture healing in rats

Low magnitude high frequency vibration (LMHFV) has been shown to improve anabolic and osteogenic responses in osteoporotic intact bones and during osteoporotic fracture healing; however, the molecular response of LMHFV during osteoporotic fracture healing has not been investigated. It was hypothesized that LMHFV could enhance osteoporotic fracture healing by regulating the expression of genes related to chondrogenesis (Col‐2), osteogenesis (Col‐1) and remodeling (receptor activator for nuclear factor‐ κ B ligand (RANKL) and osteoproteger (OPG)). In this study, the effects of LMHFV on both osteoporotic and normal bone fracture healing were assessed by endpoint gene expressions, weekly radiographs, and histomorphometry at weeks 2, 4 and 8 post‐treatment. LMHFV enhanced osteoporotic fracture healing by up‐regulating the expression of chondrogenesis‐, osteogenesis‐ and remodeling‐related genes (Col‐2 at week 4 (p = 0.008), Col‐1 at week 2 and 8 (p < 0.001and p = 0.008) and RANKL/OPG at week 8 (p = 0.045)). Osteoporotic bone had a higher response to LMHFV than normal bone and showed significantly better results as reflected by increased expression of Col‐2 and Col‐1 at week 2 (p < 0.001 for all), larger callus width at week 2 (p = 0.001), callus area at week 1 and 5(p < 0.05 for all) and greater relative area of osseous tissue (p = 0.002) at week 8. This study helps to understand how LMHFV regulates gene expression of callus formation, mineralization and remodeling during osteoporotic fracture healing. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1572–1579, 2014.