Effect of recombinant human basic fibroblast growth factor on angiogenesis during mandible fracture healing in rabbits

Objective: To investigate the effect of recombinant human basic fibroblast growth factor ( rhbFGF) on angiogenesis during mandible fracture healing in rabbit.Methods: Fifty adult white rabbits were used for animal model and randomly divided into a control group (25 rabbits) and an experimental group (25 rabbits). The membranous complex of rhbFGF and bovine type I collagen was prepared and implanted into the rabbit mandible fracture site under periosteum. The animals were sacrificed on 7, 14, 28, 56 and 84 days respectively after operation and the whole mandibles were harvested. The expression of factor Vm related antigen (F8-RA) in callus was examined with immimohistochemical staining.Results: The amounts of microvascular formation in calluses in the rhbFGF-treating group on days 7, 14, 28 and 56 were more than those of the control group (P < 0.01).Conclusions: The results indicated that rhbFGF could stimulate microvascular formation during mandible fracture healing in rabbits.     

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.     

Effects of low-dose, intermittent treatment with recombinant human parathyroid hormone (1-34) on chondrogenesis in a model of experimental fracture healing

Recent studies have demonstrated that intermittent administration of parathyroid hormone (PTH) enhances osteogenesis (hard callus formation) and increases mechanical strength in experimental fracture healing. Thus far, however, effects of PTH on chondrogenesis (soft callus formation) during fracture healing have not been fully elucidated. In the present study, we analyzed the underlying molecular mechanism by which exogenous PTH would affect chondrogenesis in a model of experimental fracture healing. Unilateral femoral fractures were produced in 2-month-old Sprague-Dawley rats. Daily subcutaneous injections of 10 microg/kg of recombinant human PTH(1-34) [rhPTH(1-34)] were administered over a 28-day period of fracture healing. Control animals were injected with vehicle solution (normal saline) alone. The results showed that, on day 14 after fracture, cartilage area in the PTH-treated group was significantly increased (1.4-fold) compared with the controls, but this increase was not observed at days 21 and 28. In the early stage of chondrogenesis (days 4-7), cell proliferation, expressed as the rate of proliferating cell nuclear antigen-positive cells, was increased in mesenchymal (chondroprogenitor) cells but not chondrocytes in the PTH-treated group compared with controls. In addition, gene expression of SOX-9 was up-regulated in the PTH-treated group on day 4 (1.4-fold), and this was accompanied by enhanced expression of pro-alpha1 (II) collagen (1.8-fold). After 14 days, there were no significant differences between groups in either cell proliferation or the expression levels of cartilage differentiation-related genes (SOX-9, pro-alpha1 (II) collagen, pro-alpha1 (X) collagen and osteopontin). These results suggest that intermittent treatment with low-dose rhPTH(1-34) induces a larger cartilaginous callus but does not delay chondrocyte differentiation during fracture healing.     

海水浸泡开放性骨折伤愈合过程中组织病理学和血管内皮细胞生长因子(VEGF)表达

目的通过观察普通开放骨折、海水浸泡开放骨折愈合过程的组织学变化和骨痂中血管内皮细胞生长因子(VEGF)的表达,了解海水浸泡开放性骨折愈合过程VEGF的作用与机制。方法新西兰大白兔59只,随机分为普通开放骨折组(对照组)24只和海水浸泡开放骨折组(实验组)35只。造成桡骨横行1.5mm缺损完全开放骨折,普通开放骨折伤组旷置3h,海水浸泡开放骨折伤组海水浸泡伤口3h,之后依次缝合伤口。于第1、3、7、14、21、28、45天处死动物。观察海水浸泡开放骨折伤在骨折愈合中不同时间的病理过程。采用RT-PCR方法检测普通开放骨折、海水浸泡开放骨折不同阶段骨痂中的VEGF的表达及变化。结果海水浸泡开放骨折伤骨痂形成延迟,骨折后第28天,对照组断端间骨痂为骨性骨痂者8例,为软骨者4例,实验组断端间骨痂为骨性骨痂者6例,为软骨者14例。海水浸泡骨折伤愈合过程中新生骨痂的VEGF表达在骨折后逐渐升高,术后14d达到高峰,之后逐渐下降,但在28d时仍保持较高水平,与一般开放骨折愈合过程的VEGF表达无显著差异(P>0.05)。结论海水浸泡使骨折骨痂形成不良率增高,骨折愈合过程有延迟倾向;但骨折愈合过程中VEGF表达无明显变化。     

骨折愈合过程中血管内皮细胞生长因子表达的实验研究

目的 观察骨折愈合过程中骨痂组织内血管内皮细胞生长因子（ｖａｓｃｕｌａｒ ｅｎｄｏｔｈｅｌｉａｌ ｇｒｏｗｔｈ ｆａｃｔｏｒ,ＶＥＧＦ）的表达,进一步探讨ＶＥＧＦ对骨折愈合的影响。方法 采用免疫组织化学方法愈合的不同阶段,骨痂组织内表达ＶＥＧＦ的细胞来源不同,同时表达程度也存在差异。结论 骨折愈合的不同时期,骨痂组织内间充质细胞、软骨细胞、成骨细胞等出现程度不同的ＶＥＧＦ表达,表明ＶＥＧＦ参与调节     

Cell proliferation and apoptosis during fracture healing.

This study investigated the relation between cell proliferation and apoptosis during fracture healing in a mouse femoral fracture model. Left femoral osteotomies were performed in 30 mature male CFLP mice immobilized with uniplanar external fixators. Six animals were killed on days 2, 4, 8, 16, and 24 postfracture for examination. Localization of cell proliferation was examined using immunohistochemistry with proliferating cell nuclear antigen (PCNA) monoclonal antibody. Apoptotic cells were visualized with the terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP)-biotin nick end-labeling (TUNEL) method. Images of each time-specific specimen were captured. The total callus area, the positively labeled cells by PCNA, and TUNEL per high-power field were quantified. Cell proliferation and apoptosis were found coexisting during the entire period of study. In the early phases of fracture healing (days 2-8), PCNA-positive labeling was predominant and peaked at day 8 and the TUNEL-positive labeling was minimal. In later stages of fracture healing (days 16-24), PCNA expression declined at day 16 as callus ossification and remodeling spread within the fracture site and apoptosis was the dominant cell activity with the TUNEL-positive labeling peaking at day 16 and declining sharply at day 24. These cell activities were reflected by the change of fracture callus, where there was a continuous increase in total callus area to day 16 and subsequent decrease at day 24. This study indicated that cell proliferation and apoptosis are coupled events during fracture repair, cell proliferation is active at the early stages, and apoptosis is active during the phase of callus remodeling.     

Mechanisms for the enhancement of fracture healing in rats treated with intermittent low-dose human parathyroid hormone (1-34).

Recent reports have demonstrated that intermittent treatment with parathyroid hormone (1-34) [PTH(1-34)] increases callus formation and mechanical strength in experimental fracture healing. However, little is known about the optimal dose required for enhancement of fracture repair or the molecular mechanisms by which PTH regulates the healing process. In this study, we analyzed the underlying molecular mechanisms by which PTH affects fracture healing and tested the hypothesis that intermittent low-dose treatment with human PTH(1-34) can increase callus formation and mechanical strength. Unilateral femoral fractures were produced and a daily subcutaneous injection of 10 microg/kg of PTH(1-34) was administered during the entire healing period. Control animals were injected with vehicle solution alone. The results showed that on day 28 and day 42 after fracture, bone mineral content (BMC), bone mineral density (BMD), and ultimate load to failure of the calluses were significantly increased in the PTH-treated group compared with controls (day 28, 61, 46, and 32%; day 42, 119, 74, and 55%, respectively). The number of proliferating cell nuclear antigen (PCNA)-positive subperiosteal osteoprogenitor cells was significantly increased in the calluses of the PTH-treated group on day 2, and TRAP+ multinucleated cells were significantly increased in areas of callus cancellous bone on day 7. The levels of expression of type I collagen (COLlA1), osteonectin (ON), ALP, and osteocalcin (OC) mRNA were increased markedly in the PTH-treated group and accompanied by enhanced expression of insulin-like growth factor (IGF)-I mRNA during the early stages of healing (days 4-7). The increased expression of COL1A1, ON, ALP, and OC mRNA continued during the later stages of healing (days 14-21) despite a lack of up-regulation of IGF-I mRNA. These results suggest that treatment of fractures with intermittent low dose PTH(1-34) enhances callus formation by the early stimulation of proliferation and differentiation of osteoprogenitor cells, increases production of bone matrix proteins, and enhances osteoclastogenesis during the phase of callus remodeling. The resultant effect to increase callus mechanical strength supports the concept that clinical investigations on the ability of injectable low-dose PTH(1-34) to enhance fracture healing are indicated.     

高能震波对骨痂中骨形成蛋白表达的影响

目的 观察高能震波（ＨＥＳＷ）对骨痂中骨形成蛋白（ＢＭＰ）表达的影响，探讨其促进骨折愈合的机理。方法 手术造成家兔双侧胫骨中段标准骨折模型，对一侧胫骨骨折部施以ＨＥＳＷ，另一侧为对照组，术后每周进行Ｘ线及组织学检查，并取骨痂组织切片用ＢＭＰ抗体进行免疫组化染色（ＳＡＢＣ法（）。结果 实验组骨痂中ＢＭＰ表达强度在第２－４周时明在于对照组（Ｐ〈０．０１），且Ｘ线摄片及组织学观察均显示实验组骨折愈合时间     

Bax deficiency in mice increases cartilage production during fracture repair through a mechanism involving increased chondrocyte proliferation without changes in apoptosis

This study sought to determine the role of the pro-apoptotic gene, Bax, in fracture healing by comparing femoral fracture healing in Bax knockout (KO) and wild-type C57BL/6J (background strain) mice. Bax KO fractures were larger, had more bone mineral content, had approximately 2-fold larger cartilage area per callus area in the first and second weeks of fracture healing, and showed an increased osteoclast surface area in the third and fourth weeks of fracture healing compared to C57BL/6J fractures. The increased cartilage area in the Bax KO fracture callus was due to increases in number of both pre-hypertropic and hypertropic chondrocytes. TUNEL analysis showed no significant differences in the number of either chondrocyte or non-chondrocyte apoptotic cells between Bax KO and C57BL/6J fractures at 7 or 14 days post-fracture, indicating that the increased number of chondrocytes in Bax KO fractures was not due to reduced apoptosis. Analysis of expression of apoptotic genes revealed that although the expression levels of Bcl-2 and Bcl-xL were not different between the Bax KO and C57BL/6J mice at 7 or 14 days post-fracture, the expression of BH3-domain only Bak and "Bik-like" pro-apoptotic gene increased approximately 1.5-fold and approximately 2-fold, respectively, in Bax KO fractures at 7 and 14 days post-fracture, compared to C57BL/6J fractures, suggesting that up-regulation of the Bak and Bik-like pro-apoptotic genes in Bax KO mice might compensate for the lack of Bax functions in the context of apoptosis. Analysis by in vivo incorporation of bromodeoxyuridine into chondrocytes within the fracture tissues indicated a highly significant increase in chondrocyte proliferation in Bax KO fractures compared to C57BL/6J fractures at day 7. The increased expression of collagen 2alpha1 and 9alpha1 gene in Bax KO fractures during early healing was consistent with an increased chondrocyte proliferation. In conclusion, this study demonstrates for the first time that Bax has an important role in the early stage of fracture healing, and that the increased callus size and cartilage area in Bax KO fractures was due to increased chondrocyte proliferation and not to reduced apoptosis or increased chondrocyte hypertrophy. The unexpected effect of Bax deficiency on chondrocyte proliferation implicates a novel regulatory function for Bax on chondrocyte proliferation during fracture repair.     

Impaired angiogenesis, early callus formation, and late stage remodeling in fracture healing of osteopontin-deficient mice.

OPN is an ECM protein with diverse localization and functionality. The role of OPN during fracture healing was examined using wildtype and OPN(-/-) mice. Results showed that OPN plays an important role in regulation of angiogenesis, callus formation, and mechanical strength in early stages of healing and facilitates late stage bone remodeling and ECM organization. INTRODUCTION: Osteopontin (OPN) is an extracellular matrix (ECM) protein with diverse localization and functionality that has been reported to play a regulatory role in both angiogenesis and osteoclastic bone remodeling, two vital processes for normal bone healing. MATERIALS AND METHODS: Bone repair in wildtype and OPN(-/-) mice was studied using a femoral fracture model. microCT was used for quantitative angiographic measurements at 7 and 14 days and to assess callus size and mineralization at 7, 14, 28, and 56 days. Biomechanical testing was performed on intact bones and on fracture specimens at 14, 28, and 56 days. Histology and quantitative RT-PCR were used to evaluate cellular functions related to ECM formation and bone remodeling. RESULTS: OPN deficiency was validated in the OPN(-/-) mice, which generally displayed normal levels of related ECM proteins. Intact OPN(-/-) bones displayed increased elastic modulus but decreased strength and ductility. Fracture neovascularization was reduced at 7 but not 14 days in OPN(-/-) mice. OPN(-/-) mice exhibited smaller fracture calluses at 7 and 14 days, as well as lower maximum torque and work to failure. At 28 days, OPN(-/-) mice had normal callus size but a persistent reduction in maximum torque and work to failure. Osteoclast differentiation occurred normally, but mature osteoclasts displayed reduced functionality, decreasing late stage remodeling in OPN(-/-) mice. Thus, at 56 days, OPN(-/-) fractures possessed increased callus volume, increased mechanical stiffness, and altered collagen fiber organization. CONCLUSIONS: This study showed multiple, stage-dependent roles of OPN during fracture healing. We conclude that OPN deficiency alters the functionality of multiple cell types, resulting in delayed early vascularization, altered matrix organization and late remodeling, and reduced biomechanical properties. These findings contribute to an improved understanding of the role of OPN in vivo and provide new insight into mechanistic control of vascularization and bone regeneration during fracture repair.     

生骨再造散对兔骨折愈合影响的实验研究

目的探讨中成药生骨再造散对兔实验性骨折愈合的影响. 方法将30只青紫蓝家兔制成双侧桡骨骨膜下3 mm骨缺损模型,随机分为生骨再造散组(A组)、仙灵骨葆组(B组)及对照组(C组),每组10只,于术后14天和31天每组各处死5只兔,按规定时间进行四环素双标记(即14天处死的兔于术后4、5天行第1次标记,术后11、12天行第2次标记;31天处死的兔于术后20、21天行第1次标记,术后28、29天行第2次标记),并分别取材,进行骨组织形态学计量检测. 结果术后14天A组与C组比较,类骨质面积密度、矿化骨痂均宽及活性成骨面、矿化表面及动态参数等差异均有统计学意义(P＜0.01);术后31天,活性成骨面、矿化骨痂均宽及吸收陷窝均深等差异均有统计学意义(P＜0.01).B组与C组比较,结果与A组和C组比较类似;但与A组比较,术后14天破骨细胞指数、矿化表面及骨形成率[组织水平(tissue level)及BMU水平(basic multicellular unit level)]差异均有统计学意义(P＜0.05),术后31天类骨质表面、吸收陷窝均深、骨形成率(BMU水平)差异均有统计学意义(P＜0.05). 结论生骨再造散在兔桡骨骨折14天前可促进类骨质分泌,加快矿化沉积速度,提高骨形成率,缩短矿化延迟时间;14～31天后则可增加矿化骨痂宽度,提高破骨细胞活性,对骨折愈合有促进作用.     

Smoking delays chondrogenesis in a mouse model of closed tibial fracture healing.

Smoking delays the healing process and increases morbidity associated with many common musculoskeletal disorders, including long bone fracture. In the current study, a murine model of tibial fracture healing was used to test the hypothesis that smoking delays chondrogenesis after fracture. Mice were divided into two groups, a nonsmoking control group and a group exposed to cigarette smoke for 1 month prior to surgical tibial fracture. Mice were euthanized at 7, 14, and 28 days after surgery. The outcomes measured were immunohistochemical staining for type II collagen protein expression as a marker of cartilage matrix and proliferating cell nuclear antigen (PCNA) staining to measure proliferation at the site of injury. Toluidine blue staining and histomorphometry were used to quantify areas of cartilaginous and noncartilaginous fracture callus. Radiographs were analyzed for evidence of remodeling after injury. At day 7 after injury, mice exposed to cigarette smoke had a smaller fracture callus with less cartilage matrix compared to controls. Proliferation was present at high levels in both groups at this time point, but proliferating cells had a more immature morphology in the smoking group. At day 14, chondrogenesis was more active in smokers compared to controls, while a higher percentage of bone was present in the control animals. At day 28, X-ray analysis revealed a larger fracture callus remaining in the smoking animals. Together, these findings show that the chondrogenic phase of tibial fracture healing is delayed by smoking. This study represents, to our knowledge, the first analysis of molecular and cellular mechanisms of healing in a smoking mouse fracture model.     

高能震波促进骨折愈合机理的探讨

目的 探讨高能震波（ＨＥＳＷ）对兔骨折愈合的影响及其机理。方法 手术造成家兔双侧胫骨标准骨折模型,对１侧胫骨骨折部施以ＨＥＳＷ;另１侧为对照。术后每周进行Ｘ线及组织学检查,并取骨折骨痂切片用骨形态发生蛋白（ＢＭＰ）抗体进行免疫组织化学染色（ＳＡＢＣ法）。结果 Ｘ线摄片及组织学观察显示,实验侧骨痂出现时间及骨折愈合时间均明显早于对照组;骨痂区毛细血管计数、ＢＭＰ表达强度在第２～４周时实验侧均明显大于     

Molecular basis for affected cartilage formation and bone union in fracture healing of the streptozotocin-induced diabetic rat

Most studies have focused on the association between diabetes mellitus (DM) and impaired osseous healing, but there is also evidence that diabetes impairs cartilage formation during fracture healing. To investigate the molecular mechanisms by which diabetes affects endochondral ossification, experiments were performed in a model of rat closed fracture healing complicated with diabetes. Diabetic rats were created by a single intravenous injection of streptozotocin (STZ), while controls were treated with vehicle alone. Fractures were made 2 weeks after STZ injection. Animals were killed at 4, 7, 10, 14, 21, 28 and 42 days following fracture, and samples were subject to radiographic, histological and molecular analyses. In the DM group, a significantly smaller cartilaginous callus was formed compared with controls throughout healing, with the cartilage area being reduced rapidly after day 14. When the bone union rate was evaluated radiographically on day 28, DM calluses exhibited a lower rate than controls. However, when evaluated on day 42, both groups showed an equivalent union rate. Cellular proliferation of chondroprogenitor cells and proliferating chondrocytes in soft calluses of the DM group was significantly reduced during early stages of healing (days 4 and 7), but no longer reduced thereafter. Moreover, expression levels of collagen type II, type X and osteopontin (OPN) were constantly low in the DM group. These results show the molecular basis for diminished cartilage formation and delayed union in fracture healing of the STZ-induced diabetic rats.     

A single local application of recombinant human basic fibroblast growth factor accelerates initial angiogenesis during wound healing in rabbit ear chamber

Local angiogenic therapy with recombinant human basic fibroblast growth factor (rhbFGF) has been used to promote wound healing. To obtain useful information for the development of optimal angiogenic therapy, we chronologically evaluated the effects of a single local application of rhbFGF on angiogenesis in a rabbit ear chamber model of wound healing by observing the subcutaneous vessel bed intravitally. New vessel formation during wound healing was macroscopically and microscopically evaluated for 5 wk. Each rabbit ear chamber received a single dose of 6 microg rhbFGF (treatment B1: n = 13), 18 microg rhbFGF (treatment B2: n = 16), or physiological saline as control (n = 13). At 1 wk the newly vascularized area was significantly larger in groups B1 and B2 than in control. At 2 wk, the vascularized areas in groups B1, B2, and control were similar. At 5 wk, the percentage of rabbits with complete vascularization was significantly larger in group B1 than in control. Capillary density at 5 wk was similar among the three groups. These results suggest that locally applied rhbFGF accelerated angiogenesis during early wound healing in rabbits; however, this effect was transient and no increase in capillary density occurred at the completion of vascularization.     

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。     

Does long-term ischemia affect the oxidant status during fracture healing?

Introduction The influence of transient circulatory arrest on oxidant status during the healing of a tibial fracture was investigated in rats by the use of a hindlimb tourniquet technique.Materials and methods One of the most reliable indicators for cytological damage is lipid peroxidation, which can be demonstrated by malondialdehyde (MDA) levels. Fifty-eight Wistar rats were used in this study. To determine the basal MDA levels of bone, 10 rats not exposed to ischemia were killed by an overdose of ether. The remaining 48 rats were randomly divided into two groups (control and ischemia). The control and ischemia groups were then randomly divided into 4 groups of 6 rats each. In 48 rats, the left tibia was fractured and fixed intramedullarly. In the ischemic group, complete acute transient ischemia for 4.5 h was imposed after the fracture. In the control group, no other intervention except the fracture was done. Rats from the control and ischemic groups were killed on days 3, 7, 14, and 28, and MDA levels were determined in tibial bone and callus tissue. The MDA levels of the control and ischemic groups were compared with basal MDA levels in the bone of 10 rats.Results There was an apparent difference between the basal and control group MDA levels on days 3 and 7 (p<0.01), between the basal and ischemic group MDA levels on days 3, 7, and 14 (p<0.01). In addition, the ischemic group showed a statistically significant increase in MDA levels on days 3, 7 and 14 compared with the control group (p<0.01).Conclusion We conclude that complete acute transient ischemia affects the oxidant status during fracture healing. This effect especially occurs during the ischemic period, inflammation, and callus formation of fracture healing.     

云南白药促进骨缺损修复及引导性骨再生的实验研究

目的：阐明云南白药促进骨缺损修复及引导性骨再生的愈合机制，为临床上治疗骨折提供理论依据。方法：36只新西兰兔制作桡骨缺损不愈合模型和引导性骨再生模型，随机均分用药组及对照组，手术后3d、1、3、5、10、12周取材，观察骨痂愈合程度的差异及骨痂组织学变化，结果：实验组有明显的促进骨缺损修复作用，并在引导性骨再生中的膜内成骨作用强于对照组，结论：云南白药对骨缺损修复及引导性骨再生有明显的促进作用。     

矩形髓内钉对实验性骨折局部微循环的影响

目的：探讨矩形髓内钉（RIN）对骨折愈合过程中骨折局部微循环的影响。方法：运用兔胫骨骨折内固定模型，通过微血管墨汁造影，组织切片观察等方法对RIN等不同内固定后骨折局部微循环的变化进行了动态对比研究。结果：骨折早期，各组皮质血容量均锐减，RIN，END组以内1／2，SPL组以外1／2的减少明显，术后7d，血容量明显恢复，各组均超过正常值。术后14d,血容量扩增至最高峰，约为正常值的6倍，之后血容量渐渐降低，术后84d接近正常。同组相比术后28d骨痂血管最丰富；同期相比RIN组骨痂血管最丰富，END组次之，SPL组最小，组间差异显著，结论：RIN对骨折局部微循环影响小，有利于骨折愈合。     

Elevated leptin expression in rat model of traumatic spinal cord injury and femoral fracture

Background

Few studies have reported a relationship between leptin induced by spinal cord injury (SCI) and healing bone tissue.

Objective

To observe serum and callus leptin expression within the setting of fracture and traumatic SCI.

Methods

Seventy-two male Sprague Dawley rats were randomized equally into four groups: control, SCI group, fracture group, and fracture/SCI group. Rats were sacrificed at 7, 14, 21, and 28 days post-fracture/SCI. Serum leptin was detected using radioimmunoassay at 1, 7, 14, 21, and 28 days, and callus formation was measured radiologically at 14, 21, and 28 days. Callus leptin was analyzed by means of immunohistochemistry.

Results

Serum leptin in the fracture group, SCI group, and combined fracture/SCI group were all significantly increased compared to control group at the 1, 7, 14, and 2-day time points (P < 0.05). Serum leptin in the combined fracture/SCI group was significantly higher than in the fracture group at 7, 14, and 21 days (P < 0.05), and higher than in SCI groups at 14 and 21days after operation (P < 0.05). The percentage of leptin-positive cells in the fracture/SCI callus, and callus volume was significantly higher than in the fracture-only group (P < 0.001).

Conclusions

Overall, elevated leptin expression was demonstrated within healing bone especially in the 21 days of a rat model combining fracture and SCI. A close association exists between leptin levels and the degree of callus formation in fractures.