Relationship among bone mineral density, collagen composition, and biomechanical properties of callus in the healing of osteoporotic fracture

Objective： To study the change and relationship among bone mineral density （BMD）, collagen composition and biomechanical properties of the callus in the healing process of osteoporotic fracture. Methods： The osteoporotic rat model and fracture model were established through bilateral ovariectomy （OV＇X） and osteotomy of the middle shaft of the right hind tibiae, respectively. Ninety female SD rats were randomly divided into OVX group and sham group. With the samples of blood and callus, roentgenoraphic and histological observation were performed for the assessment of the healing progress of the fracture, and the serum concentration of TRAP-5b, proportion of type I collagen, BMD and biomechanical properties of the callus were measured. Results： The OVX group experienced a significant delay of fracture healing. The mean serum concentration of TRAP-5b of rats in the OVX group was much higher than that in the sham group after the operation （P 〈 0.05）, but the difference at the same time point after fracture was smaller than that before fracture （P 〈 0.05）. The BMD of the callus in both groups reached the peak value at the 6 th week after fracture while the proportion of the type I collagen and the biomechanical strength reached the peak at the 8th week. Conclusions. The deficiency of estrogen after the ovariectomy could induce the up-regulation of the osteoclasts activities, whereas the potency of further activation after fracture was depressed. Although the synthesis of collagen together with its mineralization determines the biomechanical properties of new bone, the accumulation of collagen could be assessed as an index in the prediction of biomechanical strength of bones independent of the bone mineral deposition.     

Effect of Wnt/β-catenin signals on the fracture healing in transgenic mice

Objective To evaluate the effect of Wnt/β-catenin signals on the fracture healing in transgenic mice. Methods Col2al-ICAT transgenic mice were generated by the gene targeting technology with the ICAT transgene specifically expressed in chondrocytes as a competitive inhibitor to block Wnt/ β-catenin signals. The 8-week-old Col2al-ICAT mice were used in the experimental group and the wild type (WT) littermates with the same age served as the control group. A transverse osteotomy was performed at the middle of the tibia and the fracture healing was evaluated on the 7th, 9th, 14th, 21th and 28th days re-spectively after fracture. Roentgenogyaphy and histology observations were performed to evaluate the fracture healing pattern and the histomorphometric analysis was used to quantitate the cartilage callus volume / total callus volume (CV/TV) or bony callus volume / total callus volume (BV/TV). Results X-ray exam-ination revealed that on the 21st day after fracture, callus appeared at the fracture gap to form a bony bridge in WT mice while a radiolucent zone was apparent in the fracture gap in the Col2al-ICAT transgenic mice. Histology observation revealed that compared with WT mice, the formation of cartilage callus and endochondral ossification were delayed in Col2al-ICAT transgenic mice. Histomorphometric analysis indicated that the peak value of CV/TV arrived later in Col2al-ICAT transgenie mice than in WT mice. The BV/TV in Col2al-ICAT transgenic mice was significantly less than that in WT mice on 14th and 21st days after fracture (P<0.05). Conclusion The Wnt/β-catenin signals cause delayed fracture healing in Col2al-ICAT transgenic mice by affecting the cartilage callus formation and endochondral ossification.     

In situ localization of procollagen gene expression on cryosections of undecalcified fracture callus

Objective:To analyze the expression of procollagen gene in fracture callus,and to search for the technique of in situ hybridization for undecalcified skeletal tissue.Methods:In situ hybridization of procollagen gene expression was performed on the undecalcified cryosections of rat fracture callus at 7,14,and 28d.Results:The hybridization signals achieved were clear and easy to be localized with high specificity.On the 7th day,the expressions of pro α1(Ⅲ) in fibroblasts and some chondrocyte-like cells were dominant;and at the end of second week high expression of type-Ⅱ procollagen mRNA was observed in chondrocytes.At the end of fourth week,the cartilaginous callus was almost all replaced by woven bone tissue,and some type-I procollagen mRNA positive osteoblasts and hypertrophic chondrocytes were found scattering in the woven bone and remnants of cartilaginous callus.Conclusions:The modified method employed in this study is easier,quicker,and more sensitive with high specificity than the conventional technique for a situ hybridization of procollagen gene expression of decalcified rat fracture callus.The phenomenon of shared phenotype expression,which was demonstrated among cells engaged in fracture healing,indicates an important approach to reveal the mechanism of the origin,differentiation,and orientation of cells.     

Early period of fracture healing in ovariectomized rats

Objective. To evaluate the effect of osteoporosis on fracture healing through observing the hlstomorphological changes, bone mineral density of callus and expression and distribution of transforming growth factor beta 1 (TGF-β1 ), basic fibroblast growth factor (bFGF)and bone morphogenetic protein.2 (BMP-2) in ovariectomized rats. Methods. Sixty female Sprague-Dawley rats ( aged 12 weeks and weighing 235 g on average ) were randomly divided into an ovariectomized (OVX) group (n =30) anda sham-operated (SO) group ( n = 30). Ovariectomy was performed in the OVX rats and same incision was made in the SO rats. Three months later, fracture of femoral shaft was made on all the rats. Then they were killed at different time points. Callus formation was observed with histological and imethods. Results: A reduction in callus and bone mineral density in the healing femur and a decrease of osteoblasts expressing TGF-β1 near the bone trabecula were observed in the OVX rats 3-4 weeks after fracture.Histomorphological analysis revealed a higher content of soft callus in the OVX rats than that in the SO rats.Immunohistochemistry results showed that no remarkable difference in expression and distribution of BMP-2 and bFGF between the OVX and SO groups was found. Conclusions: Osteoporosis influences the quantity and quality of callus during the early period of fracture healing. The effect of osteoporosis on fracture healing has no relationship with the expression of BMP-2 or bFGF. The decreased expression of TGF-I31 in osteoblasts may cause a decrease in quality of facture healing after osteoporosis.     

Effect of substance P released from peripheral nerve ending on endogenous expression of epidermal growth factor and its receptor in wound healing

Objective: To explore the relationship between substance P (SP) released from peripheral nerve endings and the expression of epidermal growth factor (EGF) and epidermal growth factor receptor (EGFR) during wound bealing. Methods: Fifty Wistar rats were randomly divided into 2 groups, injury group and capsaicin group. In the injury group, a full-thickness skin wound on the back of the rat was taken. The wound edge and granulation tissues were taken on the 1st, 3rd, 6th, 9th, 12th days after injury, respectively. In the capsaicin group, capsaicin was injected subcutaneously on the back of the rats to destroy the sensory nerve to prevent the secretion of SP, then a wound and sample was made in the same way.Immunohistochemistry and in situ hybridization were employed to detect the expression of SP, EGF/EGFR, and EGF mRNA/EGFR mRNA in the granulation tissues.Results: In the injury group,immunohistochemical stain of SP and EGF/EGFR was located on the hair follicles and sebaceous glands at the 1st day. And the stain of SP was obvious at the 3rd day in the granulation tissues, then decreased gradually. EGF/EGFR was at low level at the 3rd day, then increased gradually and reached the peak at the 9th day, then declined. In the capsaicin group, the stain of SP and EGF/EGFR was faint and without obvious change during the wound healing process. The tendency of the EGF mRNA/EGFR mRNA expression was similar to that of EGF/EGFR. Conclusions: During wound healing, SP may promote the healing process by affecting the expression of EGF/EGFR in the erunuation tissues.     

Vascular endothelial growth factor and its receptor expression during the process of fracture healing

Objective： To study the expression regularity of vascular endothelial growth factor （VEGF） during the process of fracture healing, and the type of VEGF receptor expressed in the vascular endothelial cells of the fracture site.
Methods： The fracture model was made in the middle part of left radius in 35 rabbits. The specimens from the fracture site were harvested at 8, 24, 72 hours and 1, 3, 5, 8 weeks, and then fixed, decalcified, and sectioned frozenly to detect the expression of VEGF and its receptor at the fracture site by in situ hybridization and immunochemical assays.
Results： VEGF mRNA and VEGF expression was detected in many kinds of cells at the fracture site during 8 hours to 8 weeks after fracture. Fltl receptor of VEGF was found in the vascular endothelial cells at the fracture site during 8 hours to 8 weeks after fracture, and strong expression of flkl receptor was detected from 3 days to 3 weeks after fracture.
Conclusions： The expression of VEGF and fltl receptor appears during the whole course of fracture healing, especially from 1 to 3 weeks. Flkl receptor is highly expressed in a definite period after fracture. VEGF is proved to be involved in the vascular reconstruction and fracture healing.     

Compositional variation of fibrous callus and joint cartilage in different internal environments

Objective: To evaluate the compositional variation of Fibrous callus in the fracture site and the joint cavity and joint cartilage after being transplanted in the muscle pouch. Methods: Thirty 2-month-old New Zealand white rabbits (weighing 1-1. 5 kg) were randomly divided into two groups:a callus transplantation group (Group A,n = 15) and a cartilage transplantation group (Group B, n = 15). In Group A, closed radius fracture was made and the autologous fibrous callus was transplanted in the right knee joint cavity at 12 days postoperatively. In Group B, the right knee joint cartilage of the animals was transplanted in the autologous back muscle pouches under anesthesia. Then all the animals were killed by overdose anesthetic 3 weeks after transplantation. And the transplanted fibrous callus, the healed bones in the fracture sites and the transplanted joint cartilage were obtained for assessment of compositional variation. Results: Pure fibrous composition was found in the callus at the fracture sites in Group A at 12 days postoperatively. And for 11 out of the 15 animals, the fibrous callus was transformed into cartilaginous tissues after 3 weeks of transplantation, but the fibrous callus was absent in the other 4 animals. The fibrous calluses at the original site and the fracture locus were differentiated into bony tissues. Bony tissue transformation was found in the transplanted joint cartilages in the muscle pouch of all the animals in Group B. Conclusions:The fracture sites or joint cavity may facilitate callus differentiation in different ways:the former is helpful for osteogenesis while the latter for the development and maintenance of cartilages, and the muscle pouch is inclined to induce the osteogenic phenotype for cartilages.     

Repair of the radial defect of rabbit with polyester/ tricalcium phosphate scaffolds prepared by rapid prototyping technology

Objective： To evaluate the effects of repairing rabbit radial defects with polyester/tricalcium phosphate scaffolds prepared by rapid prototyping technology loaded with bovine bone morphogenetic protein （ bBMP）, and find new carriers for growth factors. Methods： Polyester/tricalcium phosphate scaffolds prepared by rapid prototyping technology loaded with and without bovine BMP were used to repair the 15 mm radial defect in rabbit. Then the results of radiography, histology, scaffolds degrade rates and bone mineral density （BMD） were appraised to examine the effects at the 12th week. Results ： At the 12th week postoperatively, all defects treated with bBMP were radiographically repaired. No radius implanted polyester/tricalcium phosphate scaffolds without bBMP showed radiographic and histological union. At experimental groups, longitudinal alignment of lamellar structure was observed histologically at the 12th week,indicating that remodeling of regenerated bone was complete in different degree. Of the three experimental groups, the bony regeneration and remodeling of callus in poly lactide-co-glycolide/tricalcium phosphate （PLGA/ TCP） group was the best. The BMD values were beyond 70% of normal value at the 12th week while the PLGA/ TCP scaffolds group was the highest, and no abnormalities were observed in the surrounding soft tissue in all groups. Conclusions - Polyester/tricalcium phosphate scaffolds prepared by rapid prototyping technology loaded with bovine BMP can repair a 15 mm radial defect of rabbit. As for the results, the PLGA/TCP scaffold is ideal and better than poly L-lactide-co-D, L-lactide （ PDLLA/TCP ） scaffold, but the ploy L-lactic acid （PLLA/TCP） is not so good for its low degradation rates.     

荷负电气溶胶治疗对大鼠烫伤创面白细胞介素-8、10表达的影响及意义

Objective To discuss the influence of aerosol bioelectricity on the expression of interleukin (IL) -8 and IL-10 in wound healing of burned rats. Methods The deep Ⅱ degree scalding models were established in Sprague Dawley (SD) rats. Rats were randomly divided into experimental group (n1 =20) and control group (n2 =20). The rats in experimental group were treated with aerosol bioelectricity.Samples were collected at the first to eleventh day post-scalding. Immunohistochemistry and image analysis methods were conducted to examine the expression of IL-8 and IL-10 in both experimental and control groups. Results The average wound healing time in experimental group was 7. 00 ± 1. 15 days, and that in control group was 9. 00 ± 1. 34 days. IL-8 and IL-10 were observed mainly in polylmorphonuclear and mononuclear cells in both experimental and control groups on the 1 st day. On the third day, fibroblasts abounded, IL-8 expression was increased evidently and reached a peak. The peak value (6. 73 ± 1. 36) in experimental group was lower significantly than that in control group ( 2. 85 ± 0. 72, P ＜ 0. 01). From the 5th to 11th day, IL-8 expression was declined rapidly. IL-10 was expressed in keratode cells and had the peak value in experimental group (1. 24 ±0. 15) and control group (5. 69 ± 1. 32) on the 3rd day. IL-10 expression was declined gradually from the 5th to 11th days. The expression level of IL-10 in experimental group was significantly higher than in control group from the 3rd day to 11th days post-scalding (P＜0. 01). On the 3rd day, both IL-8 and IL-10 in experimental and control groups were expressed abundantly , and there was negative relationship between them (r = - 0. 862, P ＜ 0. 01). Conclusion Aerosol bioelectricity can indicate active cells proliferation through down-regulating the expression of IL-8 and up-regulating the expression of IL-10, accelerating burned wound healing.     

荷负电气溶胶治疗对大鼠烫伤创面白细胞介素-8、10表达的影响及意义

Objective To discuss the influence of aerosol bioelectricity on the expression of interleukin (IL) -8 and IL-10 in wound healing of burned rats. Methods The deep Ⅱ degree scalding models were established in Sprague Dawley (SD) rats. Rats were randomly divided into experimental group (n1 =20) and control group (n2 =20). The rats in experimental group were treated with aerosol bioelectricity.Samples were collected at the first to eleventh day post-scalding. Immunohistochemistry and image analysis methods were conducted to examine the expression of IL-8 and IL-10 in both experimental and control groups. Results The average wound healing time in experimental group was 7. 00 ± 1. 15 days, and that in control group was 9. 00 ± 1. 34 days. IL-8 and IL-10 were observed mainly in polylmorphonuclear and mononuclear cells in both experimental and control groups on the 1 st day. On the third day, fibroblasts abounded, IL-8 expression was increased evidently and reached a peak. The peak value (6. 73 ± 1. 36) in experimental group was lower significantly than that in control group ( 2. 85 ± 0. 72, P ＜ 0. 01). From the 5th to 11th day, IL-8 expression was declined rapidly. IL-10 was expressed in keratode cells and had the peak value in experimental group (1. 24 ±0. 15) and control group (5. 69 ± 1. 32) on the 3rd day. IL-10 expression was declined gradually from the 5th to 11th days. The expression level of IL-10 in experimental group was significantly higher than in control group from the 3rd day to 11th days post-scalding (P＜0. 01). On the 3rd day, both IL-8 and IL-10 in experimental and control groups were expressed abundantly , and there was negative relationship between them (r = - 0. 862, P ＜ 0. 01). Conclusion Aerosol bioelectricity can indicate active cells proliferation through down-regulating the expression of IL-8 and up-regulating the expression of IL-10, accelerating burned wound healing.     

血管内皮生长因子对骨折愈合相关因子表达的调控

目的探讨应用和拮抗血管内皮生长因子(VEGF）对骨折愈骨相关因子表达的影响，并观察骨折愈台过程中的病理改变。方法用105只天上I=白兔制作骨折模型．随机分为对照组、应用VECF组和拮抗vEGF组，分别于伤后8、24、72b和1．3、5、8周测定各组动物骨折端相关因子的表达变化、同时取骨折端标本脱钙进行兜镜观察。结果应甩VEGF使骨折端埘BMP的表达时同提前和延良，拈抗VEGF抑制rBMP的表达，应用VEGF组伤后3J嗣时骨折端充填有纤维性骨痴，软骨骨痂和骨性骨痂．5周时新生骨以编织骨为主，8周时骨折正常愈合；括抗VH押导受伤后初期骨细胞坏死增多，1～5周各时相点骨折端均有灶性坏死出现，3同时骨折部位血管生成明显减少。结论骨折愈台过程需要多因子参与、协调，VEGF有可能是作为骨折愈台过程中的一种重要因子在发挥作用     

骨折愈合过程中血流量变化与VEGF的相关性研究

目的：探讨骨折愈合过程中血管内皮生长因子（Vascular endothelial growth factor,VEGF)对骨折端血流量变化的影响。方法：大耳白兔105只，随机分对照组，VEGF组抗VEGF组，各线于伤后8、24、72H,1,3,5,8周利用单光子放射计算机断层显像术（single photon emission computerized tomography,SPECT)测定骨折端血流量变化。结果：应用VEGF使骨折端血流量在一定时间内较对照组增高；抗VEGF可导致骨折端血流量明显减少，结论：VGEF对骨折端血压血流量变化可能影响骨折愈合，有重要意义。     

仙灵骨葆胶囊联合阿仑膦酸钠对骨质疏松骨折大鼠骨痂血管形成的影响

目的探讨仙灵骨葆胶囊联合阿仑膦酸钠对骨质疏松性骨折大鼠骨痂血管形成及VEGF、BMP-2表达的影响。方法50只雌性SD大鼠随机分为假手术组(SHAM组)、模型组(MODEL组)、仙灵骨葆组(XLGB组)、阿仑膦酸钠组(ALLSN组)、联合药物组(LHYW组),10只/组,构建骨质疏松性骨折大鼠模型,放射性X线观察评估骨折愈合,双能X线检测骨密度,Mirco-CT检测骨结构形态学参数,番红O固绿染色观察骨痂组织形态学,免疫组化检测骨痂VEGF和BMP-2蛋白表达。结果所有实验大鼠均进入结果分析。与SHAM组比较,MODEL组大鼠骨折愈合评分、骨密度、骨组织形态学参数、骨痂VEGF和BMP-2表达均显著降低(P0.05),与MODEL组比较,XLGB组、ALLSN组和LHYY组骨折愈合评分、骨密度、骨组织形态学参数、骨痂VEGF和BMP-2表达均显著升高(P0.05),尤以LHYY组最高。SHAM组骨小梁结构正常,几乎均为骨性骨痂。MODEL组骨小梁明显稀疏、断裂,未见明显骨性骨痂。XLGB组和ALLSN组骨小梁增多,排列稍紊乱,大部分为骨性骨痂。LHYW组骨小梁明显增多,排列密集整齐,大量骨性骨痂。结论仙灵骨葆胶囊联合阿仑膦酸钠可能通过介导提高骨质疏松性骨折大鼠骨生长因子VEGF和BMP-2表达,促进骨痂血管形成,加速骨痂形成,增加骨密度,改善骨结构形态,促进骨折愈合。     

The effects of cryopreserved human amniotic membrane on fracture healing: Animal study

ObjectiveThe aim of this study was to investigate the effects of human amniotic membrane (HAM) on fracture healing in an animal model.MethodsStandard tibial diaphysial fractures were created in twenty-eight Wistar-Albino rats and treated with intramedullary Kirschner wire (K-wire) and HAM (HAM (+) group) or K-wire only (HAM (–) group). Fracture healing was evaluated by histological analysis, radiologic X-ray views and callus diameter measurements at 3rd and 6th weeks postoperatively.ResultsFracture healing was histologically better in the HAM (+) group and the difference was statistically significant at both 3rd and 6th weeks postoperatively (p < 0.05). The highest histologic scores and entire woven bone formation (Huo Stage 8–9) were obtained at 6th weeks postoperatively in the HAM (+) group. Histological examination also revealed predominant fibrous tissue and partial cartilage formation (Huo Stage 2) at the postoperative 3rd week in the HAM (-) group. Equal amounts of woven bone and cartilage formation (Huo Stage 6–7) were observed at 3rd weeks postoperatively in the HAM (+) group and at 6th weeks postoperatively in the HAM (-) group. The callus diameters were greater in the HAM (+) group and the difference was statistically significant (p < 0.05) at 3rd and 6th weeks postoperatively. Although there was only a statistically significant difference (p < 0.05) at the postoperative 3rd week, radiological scores tended to be higher in the HAM (+) group at both the 3rd and 6th weeks postoperatively.ConclusionHAM is a cheap and easily accessible alternative biological material. HAM may be used to support surgical treatment of fractures, particularly where bone healing is expected to last longer.     

一氧化氮合酶在大鼠股骨闭合性骨折愈合中的表达及其意义

目的　探讨一氧化氮合酶 (NOS)在大鼠骨折愈合过程中的表达及其意义。方法　Wistar大鼠 40只建立股骨闭合性骨折模型。骨折后第 3天、1、2、4周分别处死每组 10只大鼠 ,取骨痂和对侧正常骨组织 ,苏木素 伊红 (HE)染色和免疫组织化学链霉抗生物素蛋白 过氧化物酶(SP)法观察骨折愈合及诱生性一氧化氮合酶 (iNOS)、内皮性一氧化氮合酶 (eNOS)和神经性一氧化氮合酶 (bNOS)在骨痂中的表达情况。结果　iNOS主要在成纤维细胞和成软骨细胞中表达 ;eNOS主要在增生血管内膜表达 ,bNOS没有表达。正常的股骨组织内没有NOS的表达。表达iN OS和eNOS的阳性细胞不同 ,并且不同时期其阳性细胞数也不同 ,iNOS在骨折后 1周最多 (P <0 .0 5 ) ,eNOS在骨折后 2周最多 (P <0 .0 1)。结论　iNOS和eNOS在骨折愈合中的表达具有时效性 ,它们在不同细胞内的表达提示一氧化氮可能对骨折愈合起一定的调节作用     

Effect of fluvastatin on vascular endothelial growth factor in rats with osteoporosis in process of fracture healing

OBJECTIVE: To explore the effect of fluvastatin on vascular endothelial growth factor (VEGF) in rats with osteoporosis in the process of fracture healing. METHODS: Fractures at the intermediate piece of the femur were made on 72 Sprague Dawley (SD) rats (weighing initially 290-340 g and aged 6 months) with osteoporosis after ovariectomy for three months, then these rats were divided randomly into the medication administration group (the experimental group) and the control group, 36 rats each. In the experimental group, the rats received fluvastatin lavage (10 mg/kg per day) since the next day of operation lasting for 6 weeks, and the rats in the control group received placebo. Then the expression of VEGF and VEGF mRNA in bony callus of the two groups was measured respectively with immunohistochemistry and in situ hybridization on days of 3rd, 7th, 14th, 21st, 28th, and 42nd, and image analysis was made with real-color image analysis machine. RESULTS: No difference was found in the cellular localization of VEGF and VEGF mRNA gene expression between the experimental group and the control group in process of fracture healing and their expression modes were almost similar. On the 14th day postoperatively, the positive extent of positive cells in the experimental group was higher than that of the control group (P < 0.05). CONCLUSION: Fluvastatin can promote the VEGF level in rats with osteoporosis in process of fracture healing.     

Role of platelet-rich plasma in acceleration of bone fracture healing

Platelet-rich plasma (PRP) is a common therapy for acceleration of maxillofacial and spinal fusion bone-graft healing. This study analyzes the therapeutic role of PRP during long-bone fracture healing evaluated Lewis rats. Following creation of unilateral open femur fractures, either 500 microL thrombin-activated PRP (PRP treated group) or 500 microL saline (control group) were applied once to the fracture site. Fracture healing was analyzed after 1 and 4 weeks. Following 4 weeks of fracture healing, radiographic analysis demonstrated higher callus to cortex width ratio (P < 0.05) in the PRP group (PRP: 1.65 +/- 0.06; control: 1.48 +/- 0.05). Three-point load bearing showed increased bone strength following PRP treatment (PRP: 60.85 +/- 6.06 Newton, control: 47.66 +/- 5.49 Newton). Fracture histology showed enhanced bone formation in the PRP group. Immunohistochemistry and Western-blotting demonstrated healing-associated changes in transforming growth factor (TGF)-beta1 and bone morphogenetic protein (BMP)-2. Our results suggest that PRP accelerates bone fracture healing of rat femurs via modulation of TGF-beta1 and BMP-2 growth factor expression.     

成骨细胞移植促进老龄鼠骨质疏松性骨折愈合过程中VEGF的动态变化

目的：动态观察在幼龄成骨细胞移植促进骨质疏松性骨折愈合过程中，VEGF在不同时相的表达及其生物学意义。方法：通过建立老龄骨质疏松SD大鼠骨折的动物模型，并将体外培养的SD雄性乳鼠成骨细胞移动到SD雌性鼠老年骨质疏松性骨缺损部位，利用免疫组化及原位杂交检测骨折愈合过程中不同时间相的移植标本VEGF、VEGFmRNA的表达，并作图像分析、绘出其动态变化图。结果：实验组VEGF、VEGFmRNA均在7d左右可见有阳性表达的细胞，14d有分泌,高峰其中以软骨细胞中阳性最强，21 d分泌量开始下降，56d后基本消失。而对照且未见明显分泌高峰。结论；成骨细胞细胞促进老龄鼠骨质疏松性骨折愈合，其机制可能是通过促进VEGF的转录和表达，从而促进骨折部位建立良好的血液循环，加速骨形成。     

转化生长因子-β1在糖尿病骨折延迟愈合大鼠中的表达

目的 观察转化生长因子-β1(TGF-β1)的表达,探讨其对糖尿病骨折延迟愈合的影响.方法 70只大鼠随机分为对照组和链脲佐菌素按60 mg/kg诱导的糖尿病组,血糖>11.2mmol/L为诱导成功.均造成左侧胫骨骨折,于1、2、3、4、6、8周摄X片,取骨痂苏木素-伊红(HE)染色,免疫组织化学和酶联免疫吸附试验(ELISA)检测骨痂及血清TGF-β1.结果 X片和HE染色均示实验组较对照组骨形成滞后;实验组4周TGF-β1表达达高峰,迟于对照组3周,3周灰度值:实验组189.59±2.76,对照组166.74±1.33(P<0.05),3周血清含量:实验组(12.05±1.56) μg/L,对照组(17.48±0.56)μg/L(P<0.05).结论 糖尿病大鼠骨折后血清及骨痂TGF-β1减少是致其延迟愈合的原因之一.     

骨形成蛋白和转化生长因子-β对兔尺骨骨折愈合后生物力学性能的影响

目的 探讨外源性骨形成蛋白(BMP)和转化生长因子—β(TGF—β)对骨折愈合后生物力学性能的影响。方法 36只日本大耳白兔，体重3．5～4．5kg。随机分成4组：空白对照组、TGF—β组、BMP组和TGF—β BMP组，每组9只。采用兔尺骨骨折模型，在骨折局部将聚乳酸(PAL)为载体制备成TGF—β／PAL、BMP／PAL、TGF—β BMP／PLA缓释系统，手术当天将各缓释系统植入骨折区，对照组在相应部位置入PAL，术后50天取材，通过三点弯曲法测骨折愈合后整体骨弯曲结构力学性能的变化。取断端密质骨，用三点弯曲、压缩和拉伸方法测骨试件的材料力学特性的变化，同时测骨痴的几何参数和骨密度的变化来对骨折愈合进行评估。结果 治疗组尺骨的几何参数，整体骨弯曲的破坏载荷、极限强度和弹性棋量，骨试件的弯曲、压缩和拉伸的极限强度，以及弯曲和压缩的弹性棋量明显高于对照组，各治疗组与对照组比较，具有统计学意义(P＜0．01)，TGF—β BMP组高于TGF—β和BMP组；TGF—β组高于BMP组，各治疗组之间两两比较，有统计学意义(P＜0．05)。在骨密度方面，各治疗组与对照组之间无明显差异。结论 兔骨折周围局部应用外源性TGF—β和BMP可促进骨痴形成，增强骨折愈合后骨组织的生物力学强度，TGF—β的作用优于BMP，联合应用优于单用一种生长因子，在促进骨折愈合方面具有协同作用。