肉鸡骨骼发育的调控机制

肉鸡骨骼发育主要是通过软骨内骨化完成的。在软骨内骨化的进程中,生长板软骨细胞经历增殖、肥大、转分化和软骨基质矿化等,最终成骨逐渐取代软骨原基,实现骨骼的线性延长。软骨内成骨是一个复杂精密的过程,由SOX9、RUNX2、MEF2C、OSX、TGF-β、BMP2、FGFs、IHH和PTHrP等多种信号因子和转录因子协调调控,这些调控因子由生长板不同区的软骨细胞表达或特异性的调控软骨细胞的增殖、分化及血管侵入等过程。在家禽养殖中,肉鸡常发腿病且治疗难度大,而有关肉鸡腿病发病机制的研究报道相对较少。本文综述了骨形成过程及具体的分子调控机制,为了解肉鸡腿病的发生以及提供有效治疗方案提供参考。     

Use of extensible internal device in the femur of young dogs.

An extensible internal device (EID) was developed to preserve growth plate during the treatment of fracture complications or segmental bone loss from tumour resection in children. Since this type of extensible, transphyseal, internal fixation device has only been used in a few paediatric cases; the aim of this study was to evaluate an in vivo canine study, a surgical application of this device, and its interference with longitudinal growth of the non-fractured distal femur. Ten clinically healthy two- to three-month-old poodles weighing 1.5-2.3 kg were used. Following a medial approach to the right distal femur, one extremity of the EID, similar to a T-plate, was fixed in the femoral condyle with two cortical screws placed below the growth plate. The other extremity, consisting of an adaptable brim with two screw holes and a plate guide, was fixed in the third distal of the femoral diaphysis with two cortical screws. The EID was removed 180 days after application. All of the dogs demonstrated full weight-bearing after surgery. The values of thigh and stifle circumferences, and stifle joint motion range did not show any difference between operated and control hindlimbs. The plate slid in the device according to longitudinal bone growth, in all but one dog. In this dog, a 10.5% shortening of the femoral shaft was observed due to a lack of EID sliding. The other dogs had the same longitudinal lengths in both femurs. The EID permits longitudinal bone growth without blocking the distal femur growth plate if appropriately placed.     

Morphological changes of the cartilage and bone in newborn piglets evoked by experimentally induced glucocorticoid excess during pregnancy

The study examined articular and growth plate cartilages as well as bone tissues in the offspring of sows treated with glucocorticoid during the last 45 days of pregnancy (dexamethasone at the dose of 0.03 mg/kg body weight intramuscularly, every second day). The offspring were tested at the birth and basal morphology for both articular and growth plate cartilages, and the histomorphometry of trabeculae of the epiphysis and metaphysis of femur and tibia were established. The concentration of selected cytokines and the activity of bone alkaline phosphatase were determined in blood serum. Maternal dexamethasone (DEX) administration reduced the thickness of proliferative, resting and hypertrophic zones of growth plate of femur and tibia of male piglets when compared with the control. DEX significantly reduced the thickness of the resting zone in both bones. It also elongated proliferative and hypertrophic zones of the growth plate in the femur as well as the hypertrophic zone in the tibia of female piglets when compared with the control group. Moreover, DEX decreased the articular cartilage thickness of the tibia in female piglets and enhanced the articular cartilage thickness of the femur in male piglets. Articular cartilage was highly cellular, and chondrocytes were separated by thin septa of matrix. An analysis of the trabecular bone architecture in male piglets showed a loss of the trabecular bone by thinning and DEX‐related increase in trabecular porosity. Moreover, the cortical bone looked similar to the trabeculae because of trabecularization of the cortex. There was a DEX that reduced serum osteocalcin and BAP concentrations in both female and male newborn piglets, whereas the serum IL‐1 and Il‐6 was reduced only in male piglets. The obtained results demonstrated that DEX administration to sows during the last 45 days of pregnancy might cause the growth to slow and eventually to stop, especially in male piglets. It might lead to an alteration within the cartilage during its normal function, and with the time, arthritic changes can follow.     

An avian model of limb deviation induced by periosteal surgery

A model of limb deviation induced by hemi-circumferential periosteal stripping of the distal tibiotarsus of domestic chicks is described. This model has been developed to study the effects of periosteal stripping on the cellular, mechanical, vascular, and biochemical status of the immature bone and growth plate. It is hoped that such studies may further elucidate the mechanisms involved in altered bone growth following periosteal stripping techniques which are used in human and equine orthopaedics for the management of leg length discrepancies and angular limb deformities respectively (Auer and Martens 1980, Warrell and Baker 1987). Hemi-circumferential periosteal stripping of the left distal tibiotarsus of 28-day-old chicks resulted in significant change in metaphyseal-diaphyseal angle with time, compared to both the controls and the untreated right legs (P<0.0001). This model of limb deviation developed rapidly and consistently, and the procedures were well tolerated by the birds over the short survival time (maximum 28 days).     

Effect of diet on longitudinal bone growth and osteochondrosis in swine

Weanling gilts were fed either a 12% or 16% protein diet for 10 weeks. Animals fed the 12% protein diet had reduced body weights and reduced longitudinal bone growth as measured in the distal radial growth plate. There was no difference in the growth plate widths between the two animal groups, but there was a significant reduction in the daily rate of cell production in the proliferative zone of animals fed the 12% protein diet. No effect of diet on the rate of expansion of the epiphysis at the articular-epiphyseal junction of the distal femur or humerus could be detected. All animals in both groups had morphologic cartilage lesions consistent with early changes associated with osteochondrosis (OCD), and there was no difference in the lesion morphology between the dietary groups. Areas of disorderly endochondral ossification in the radial growth plate were associated with perpendicular growth cartilage infractions. Growth plate lesions were characterized by increased widths of the maturing cartilage zone without increased width of the proliferative zone or an increase in the daily rate of cell production. Focal growth plate lesions developed because of a transitory inhibition of cartilage mineralization and resorption. Disorderly foci of endochondral ossification beneath articular cartilage were characterized by an area of chondrocyte necrosis which prevented normal cartilage matrix mineralization. Lamellae of cartilage necrosis were also present within the reserve zone of the articular cartilage. These were associated with abnormalities of the cartilage canal vessels, and chondrocyte necrosis was considered to precede degenerative changes in articular cartilage matrix.(ABSTRACT TRUNCATED AT 250 WORDS)     

Molecular analysis of defect healing in rat diaphyseal bone.

Spatial expression of messenger ribonucleic acid (mRNA) for osteoblastic marker in drill hole defect healing of adult male rats was analyzed by in situ hybridization. The defect was filled with hematoma 3 days after surgery, expressing Type I collagen mRNA. Hematoma was replaced with fibrous tissue on day 7, and then with new trabecular bone on day 10, originated from the intra-medullary space, respectively. mRNA for Type I collagen, parathyroid hormone 1 receptor (PTHIR), and alkaline phosphatase (ALP) were expressed in the same cell population of fibrous tissue adjacent to newly-formed trabecular bone, and in osteoblasts lining the newly-formed trabecular bone. Hematopoietic marrow with osteoclasts subsequently invaded the region, also from the intra-medullary space, replacing all the new trabecular bone by day 21, except for a thin sub-periosteal layer. mRNA for Type I collagen, PTH1R and ALP was expressed on the periosteal surface of thin layer. Although cartilage formation was not histologically visible, mRNA for Type II collagen was weakly detected in the majority of osteoblasts lining the newly-formed trabecular bone.     

Histological disorders related to the focal disappearance of the epiphyseal growth plate in rats induced by high dose of vitamin A

The histological disorders related to the focal disappearance of the epiphyseal growth plate were examined histochemically in the proximal tibia of rats administered a high dose of vitamin A. Animals were given 100,000 IU/100 g body weight/day of vitamin A for 5 days from 4 weeks after birth (VA rats) or given deionized water as control and sacrificed on Day 12 and 19 of the experiment. Tibiae were examined by immunohistochemistry for type I, II and X collagens, lectin-histochemistry for Helix pomatia and backscattered electron imaging. On Day 12, the abnormally developed calcified cartilage matrix was detected within the epiphyseal growth plate in VA rats. The uncalcified cartilage matrix contained type I collagen but lacked type II collagen. In addition, the eroded regions accompanied with numerous osteoclasts and osteoblasts were detected in the epiphyseal growth plate. On day 19, eroded regions penetrated the epiphyseal growth plate to result in its focal disappearances with the eroded surfaces entirely covered with bone tissue in VA rats. These findings suggested that the cartilage matrix of the epiphyseal growth plate was abnormally calcified and showed the phenotypes like bone matrix. The eroded regions of the epiphyseal growth plate seemed to be caused by the invasion of osteoclasts into the altered cartilage matrix and might develop to the focal disappearances by the modeling or remodeling due to action of osteoclasts and osteoblasts.     

Femoral Fracture Repair Using a Locking Plate Technique in an Adult Captive Polar Bear (Ursus Maritimus)

Objective— To report successful femoral fracture repair in a polar bear. Study Design— Case report. Animals— Female polar bear (Ursus maritimus) 5 years and ～250 kg. Methods— A closed, complete, comminuted fracture of the distal midshaft femur was successfully reduced and stabilized using a compression plating technique with 2 specialized human femur plates offering axial, rotational, and bending support, and allowing the bone to share loads with the implant. Postoperative radiographs were obtained at 11.5 weeks, 11 months, and 24 months. Results— Bone healing characterized by marked periosteal reaction was evident at 11 months with extensive remodeling evident at 24 months. No complications were noted. Conclusions— Distal mid shaft femoral fracture was reduced, stabilized, and healed in an adult polar bear with a locking plate technique using 2 plates. Clinical Relevance— Previously, femoral fractures in polar bears were considered irreparable. Use of 2 plates applied with a locking plate technique can result in successful fracture repair despite large body weight and inability to restrict postoperative activity.     

Percutaneous biopsy of the proximal humeral growth plate in dogs

A percutaneous biopsy technique for the study of endochondral bone formation in the dog was developed. With the dogs under general anesthesia or sedated with a combination of a tranquilizer and a local anesthetic, biopsy specimens were obtained from the proximal growth plate of the humerus with the use of a Jamshidi bone biopsy needle. Biopsy specimens were structurally intact, and contained epiphysis, growth plate, and metaphysis. The procedure proved to be a simple, safe technique, which caused minimal discomfort for the patient and did not affect the growth of the proximal end of the humerus, even after multiple biopsies.     

Recombinant Bone Morphogenetic Proteins: Novel Substances for Enhancing Bone Healing

Bone morphogenetic proteins (BMPs) are differentiative factors whose principal function is to induce transformation of undifferentiated mesenchymal cells into chondroblasts and osteoblasts in a dose-dependent manner. Bone morphogenetic proteins have been isolated postnatally in mammals from bone matrix, periosteal cells, mesenchymal cells of marrow stroma, tooth anlagen, and cells of osteosarcoma and chondrosarcoma. Distribution in additional embryonic tissues implies a broader organogenic function. Bone morphogenetic proteins are the only differentiative factors able to singularly induce de novo bone formation in vitro and in vivo. Recombinant DNA technology allows their production in large and highly purified quantities. The BMPs' osteoinductive ability has been shown with a variety of carriers including collagens and polymers at heterotopic and orthotopic sites in a wide range of species. They are presently being readied for clinical use as alternatives to bone grafts. Other potential applications include use as pulp capping agents, promoters of implant osteointegration and soft tissue reunion with bone, treatments for nonadaptive bone disease, and implants for use with mitotically expanded skeletal stem cell populations. Errors in the genetic coding of BMPs may manifest as clinical disease entities.     

Influence of short-term confinement and exercise on tibia development in growing pigs

The influence of short-term confinement and moderate exercise on tibia development was investigated in growing pigs (36-41 kg, 10 weeks at the beginning of the study). Animals were kept for 2 weeks either in individual crates of 0.8 m(2) ('confinement', n = 4) or kept in groups of four animals in large crates of 5.6 m(2) without ('control') or with additional exercise (30 min walking at 5 days/week; 'exercise'). Bone density and morphological parameters were evaluated by computer tomography (CT). Periosteal apposition and longitudinal growth were determined after polychrome sequential labelling in weekly intervals. Cortical areas of the cross sections at the mid-shaft and at 75% of the length of the bone measured distal to the carpus by CT were significantly correlated to each other (r = 0.70) and revealed a significant reduction in confined animals. This difference was explained by lower periosteal apposition rates in these animals compared with exercised and group-housed pigs. Similarly longitudinal growth and the formation and calcification of spongiosa of the tibiae were inhibited by confinement. Thus, 2 weeks of confinement led to significant differences in bone growth and metabolism in young growing piglets when compared with animals with moderate activity.     

Experimental T-2 toxicosis in sheep.

Lambs received T-2 toxin at a rate of 0.6 or 0.3 mg/kg body weight per day in a protein reduced diet for 21 days to study the immunological and pathological effects of T-2 toxin in sheep. Blood was collected before T-2 treatment and on days 7, 14 and 21 of the trial for hematological and biochemical examination and for the separation of peripheral blood lymphocytes for the mitogen assay. Myeloid:erythroid ratios were determined from sternal bone marrow samples taken a day before T-2 treatment began, on day 12 and at death (day 22). Lambs treated with 0.6 mg/kg body weight of T-2 toxin daily were leukopenic on day 7 and lymphopenic on days 7 and 14. Also, on day 7, the mitogenic responses of these lambs to the B-cell mitogen, lipopolysaccharide, were significantly depressed and prothrombin times were prolonged. At necropsy, lymphoid atrophy of mesenteric lymph nodes and spleens was most marked in lambs treated with 0.6 mg/kg body weight of T-2 toxin per day. To the authors' knowledge, this is the first report of leukopenia, lymphopenia and lymphoid depletion in ruminants fed T-2 toxin.     

Alterations in bone remodeling in the femur after medullary reaming and cemented hip arthroplasty in dogs.

OBJECTIVE: To determine whether medullary reaming alone, or followed by cemented hemiarthroplasty, influenced porosity, vascularity, and new bone formation in the proximal portion of the femur in dogs. ANIMALS: 12 adult mixed-breed dogs. PROCEDURE: Unilateral femoral head and neck excisions were performed, followed by femoral medullary reaming in 6 dogs and femoral medullary reaming and cemented hemiarthroplasty in 6 dogs; the contralateral femur was used as a control. All dogs were euthanatized 28 days after surgery, and femurs were harvested. Vascularity, porosity, and new bone formation were quantified for all femurs of dogs from both groups at 3 proximal-to-distal levels, 3 regions (periosteal, midcortical, and endosteal), and 4 quadrants (cranial, caudal, medial, and lateral) of the femur. RESULTS: Medullary reamed and cemented hemiarthroplasty femurs had significant increases in vascularity and porosity at all levels and in new bone formation at levels 2 and 3. Porosity was increased significantly in the periosteal region of the cemented hemiarthroplasty (9.7+/-0.7%), compared with control (2.3+/-0.2%) and medullary reamed (8.4+/-0.7%) femurs. Porosity was increased in the caudal and medial quadrants in the medullary reamed and cemented hemiarthroplasty femurs; vascularity results were similar. CONCLUSION: Increased porosity, vascularity, and new bone formation in reamed and cemented hemiarthroplasty-treated femurs supports the theory that surgical trauma associated with medullary reaming is an important factor in early cortical bone loss after hip arthroplasty. CLINICAL RELEVANCE: Femoral remodeling associated with reaming and broaching is appreciable but may be only a temporary response, whereas other factors may be responsible for chronic cortical bone loss.     

Use of the fluorochromes xylenol orange, calcein green, and tetracycline to document bone deposition and remodeling in healing fractures in chickens.

The fluorescent calcium binding dyes xylenol orange, calcein green, and tetracycline were used successfully to sequentially label new bone deposition and bone remodeling during the healing of rigidly fixed humeral fractures in the chicken. Xylenol orange and calcein green, administered subcutaneously at 90 mg/kg and 10 mg/kg, respectively, provided easily identified and differentiated bands in newly deposited bone within periosteal and endosteal calluses, intercortical gaps, and screw holes. Tetracycline, administered at 50 mg/kg per os by crop tube, labeled bone faintly in a non-specific manner. Parenteral administration of the same compound might have yielded better results.     

Evaluation of bone toxicity in various bones of aged rats

The aim of the present study was to provide a method for evaluating bone toxicity induced by drugs in various bones in aged rats. Male Crl:CD (SD) rats at 46 weeks of age were administered 15 mg/m(2) body surface area of doxorubicin, which effects the growth plate in weanling rats, weekly for 9 weeks by intravenous injection, and the femur, sternum, humerus and tibia were examined histopathologically. In the doxorubicin-treated group, thinning of the growth plate was remarkably observed in the proximal tibia and humerus; however, these changes were not observed in other regions. In addition, the osteoclast number per bone perimeter in the proximal tibia was significantly higher than others in control aged rat. Thus, recognizing the various histological reactions related to the time of epiphyseal closure is important for evaluating bone toxicity in aged rats.     

Effect of prostaglandin E1 on the periosteal regional acceleratory phenomenon in fractured ribs: histomorphometric study in beagles

Transverse fractures were made surgically in the midshaft of the left 9th and 10th ribs in adult Beagles. A buffer vehicle (n = 4) or 0.2 mg of prostaglandin (PG) E1/day (n = 6) was injected into the fracture sites twice a day for 10 days, and dogs were euthanatized on day 30. Double-pulsed fluorescent labels were given with each of 2 fluorochrome markers--calcein before surgical treatment and oxytetracycline HCl before euthanasia. Histomorphometric analysis was carried out on specimens collected in adjacent regions of the healing defects. The surface extent and width of the osteoid on fractured (P less than 0.01, P less than 0.05, respectively) and nonfractured (P less than 0.05) sites in the treated group were greater than those in the nontreated group. The net loss of mineralizing surfaces was noticed on both ribs of both groups. Of 11 samples on the fractured side in the treated group, 4 contained periosteal new bone proliferation. There was increased osteoid formation and decreased mineralizing surfaces in the PGE1-treated group. Seemingly, administration of PGE1 induced bone matrix formation on periosteal envelope adjacent to a fracture site and its contralateral matching site.     

Effect of dietary vitamin A, ascorbic acid and their interaction on turkey bone mineralisation.

At early ages, added dietary ascorbic acid did not affect growth or femur mineralisation of poults. In poults after 8 and 12 weeks, femur mass was reduced by 3000 mg ascorbic acid per kg diet. 2. Plasma calcium and magnesium were not influenced differently by 1000, 4000 and 16,000 IU vitamin A/kg diet, but plasma phosphorus was decreased by the 16,000 level. 3. Vitamin A at 1000 or 16,000 IU/kg diet reduced growth in both sexes to 12 weeks of age compared with the NRC recommended 4000 IU/kg diet. In males, the growth retardation continued to 18 weeks. 4. Vitamin A at 16,000 IU/kg reduced femur development as measured by femur weight to body weight or to femur length ratios.     

Osteochondrosis and Arthrosis in Pigs: VI. Relationship to Feed Level and Calcium,Phosphorus and Protein Levels in The Ration

Eight feeding experiments, each comprising 48 boars or gilts, were carried out. The factors feed level, Ca, P and protein levels were varied within practical physiological limits. The animals were slaughtered at close to 100 kg live weight. Lesions in joints and bones were of a noninfectious, non-rachitic nature and of the osteochondrosis and arthrosis type. Ten to 12 g Ca and approx. 10 g P/kg ration gave histomorphologically seemingly more optimum structure of the spongious bone tissue and a higher ash percentage in bones than 7 g Ca and 6 g P, or unbalanced mineral levels in the ration. However, there was no significant difference in degree or incidence of joint and bone lesions between mineral groups. Neither were there such differences present between feed level groups or protein level groups. This may for the feed level groups be partly due to the low feed level pigs having a longer period of time during which they were highly susceptible to the development of lesions. The low feed level animals had longer long bones at 100 kg live weight than the high feed level animals. The length of the vertebral column was, however, approximately similar in the 2 feed level groups. The angles of the condyles and head of the femur according to the length axis were influenced by feed level or growth rate, most probably by an effect on the endochondral ossification.     

Evaluation of biocompatible osteoconductive polymer as an orthopedic implant in dogs.

The biocompatibility and osteoconductive properties of biocompatible osteoconductive polymer (BOP), a synthetic implant, were evaluated. Bilateral oval cortical defects (1 x 2 cm) were made in the lateral subtrochanteric area of the proximal portion of the femur in 16 dogs that later were treated with BOP fiber (n = 16) or autogenous cancellous bone (n = 11), or were not treated (n = 5). The BOP block was attached extraperiosteally to the proximal portion of the humerus in 6 dogs. Radiographic assessment of surgery sites was performed at 4-week intervals, and histologic evaluation was performed at 4, 8, 16, and 24 weeks after surgery. Radiographic signs of bone healing were not observed in defects treated with BOP fiber. Defects treated with cancellous bone or not treated had radiographic signs of progressive bone ingrowth. Radiographic evidence of periosteal new bone formation near control and BOP-treated defects was observed 4 weeks after surgery; increased periosteal reaction was associated with BOP fiber. This new bone had resorbed by week 24, except bone adjacent to BOP fiber, where continued periosteal reaction was apparent. Histologic evidence of bone formation was observed extending to, but not incorporating, BOP fibers. The BOP fibers became surrounded by a fibrous capsule, and fibrovascular connective tissue infiltrated between and into BOP fibers, but minimal bone formation incorporated the BOP material during the follow-up period. During that time, active periosteal new bone formation was evident adjacent to the BOP fibers. Defects treated with cancellous bone or not treated healed by ingrowth of cancellous bone during the first 12 weeks after surgery and by reformation of the lateral cortical wall by week 24. The BOP blocks became surrounded by a fibrous capsule, but connective tissue or bone ingrowth into BOP blocks was not observed. Results indicate that BOP is not osteoconductive within a 6-month time frame when used in subtrochanteric femoral defects or when placed extraperiosteally on the proximal portion of the humerus of clinically normal dogs.     

Effects of large granular lymphocyte leukemia on bone in F344 rats

Large granular lymphocyte (LGL) leukemia was induced in 40 F344 rats by inoculating them with neoplastic cells to evaluate the effect of acute leukemia on bone remodeling and calcium balance. The rats developed leukemia and splenomegaly by 9 days after inoculation. The rats had reduced body weight (day 12), food intake (days 4, 8, 12), urine production (day 12), and fecal output (day 12). Serum calcium and phosphorus and urinary excretion of calcium and phosphorus were decreased on days 8 and 12 in leukemic rats. Static bone histomorphometry of trabecular bone in lumbar vertebrae demonstrated reduced bone area, no change in the number of osteoclasts, and reduced osteoclast perimeter at day 12. Dynamic bone histomorphometry revealed reduced double labeled perimeter, mineralizing perimeter, trabecular mineral appositional rate, and bone formation rate in rats with LGL leukemia at days 9 and 12. There was no change in periosteal mineral appositional rate. Rats with leukemia and intramedullary neoplastic cells had a reduction in bone formation rate that resulted in a loss of trabecular bone.