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1.
OBJECTIVE: To characterize the nucleotide sequence of equine platelet-derived growth factor (PDGF)-A and -B and analyze temporal expression of these genes in equine tendon after induced tendinitis injury. Animals-18 mature horses. PROCEDURES: Genes for equine PDGF-A and -B were reverse transcribed and sequenced from synovial tissue mRNA obtained from a 3-year-old horse. Collagenase-induced lesions were created in the tensile region of the superficial digital flexor tendon in 14 horses; 3 horses served as uninjured control animals. Tendons were harvested and total RNA was isolated from experimental horses 1, 2, 4, 8, and 24 weeks after collagenase injection. Temporal gene expression for PDGF-A and -B was determined by use of quantitative PCR analysis. RESULTS: Equine PDGF-A shared 83.8% sequence and 87.5% peptide homology with human PDGF-A, with a discrepancy of 70 bp from the human sequence. Equine PDGF-B was similar in length to the human gene, sharing 90.3% and 91.7% nucleotide and peptide identity, respectively. Expression of PDGF-A mRNA in collagenase-induced tendinitis lesions was unchanged, compared with expression for normal control tendon, and remained steady throughout the 24-week study. Expression of PDGF-B mRNA decreased over time, and the expression at 24 weeks was significantly reduced, compared with expression in normal and acutely injured tendon. CONCLUSIONS AND CLINICAL RELEVANCE: Injured tendon mounts a minimal constitutive PDGF-A or -B mRNA response. Serial exogenous treatment with either PDGF isoform within the first 2 to 4 weeks after tendon injury may bolster the meager PDGF paracrine-autocrine intrinsic response to injury.  相似文献   

2.
OBJECTIVES: To determine the full-length complementary DNA (cDNA) sequence of equine retinal and pineal gland phosducin (PHD) and to clone these sequences. SAMPLE POPULATION: Samples of equine retinal RNA. PROCEDURE: A primer set was designed for use in identifying a fragment of the equine PHD nucleotide sequence, derived from retinal RNA samples, and subsequently for use to deduce specific primers for additional examination. The full-length cDNA was determined by the method of rapid amplification of cDNA ends (RACE). For full-length cDNA, newly designed primers were used. Nucleotide sequences were analyzed by use of computer software. The deduced amino acid sequence was compared with sequences of PHD reported for other species. In addition, the sequence of equine pineal PHD was cloned. RESULTS: The cDNA nucleotide sequence for equine PHD was 1,209 base pairs (bp) in length with an open-reading frame encoding a protein of 245 amino acids and a calculated molecular mass of 28.214 kd. Similarity with amino acid sequences of PHD from other species was 89 to 93%. Sequences of equine PHD from retina and pineal gland were identical. Equine PHD contained a peptide sequence with 100% homology to an uveitopathogenic peptide reported for rat PHD. CONCLUSIONS: Equine PHD is a highly conserved protein that has homology of immunologic interest with rat PHD. These results establish a basis for studying the role of PHD in ocular inflammation of horses.  相似文献   

3.
OBJECTIVES: To determine whether quantitative analysis of sonographic brightness could be used to detect healing of an induced injury of the superficial digital flexor tendon in horses and whether rate of healing was influenced by equine recombinant growth hormone. ANIMALS: 8 clinically normal Standardbreds. PROCEDURES: A localized injury was created in the left and right superficial digital flexor tendons of each horse by injection of 2,000 units of collagenase. After injury, 4 horses received equine recombinant growth hormone, a possible promoter of tendon healing. Sonographic images (7.5 MHz) of the flexor tendons and ligaments of the metacarpal region were recorded on videotape prior to injury and weekly for 7 weeks after injury. Images were digitized, and sonographic brightness of tendons and ligaments was calculated. RESULTS: Collagenase-induced injury was sonographically similar to naturally occurring injury. After injury, sonographic brightness of the tendon decreased; after 3 weeks, brightness progressively increased, although by 7 weeks brightness had not returned to preinjury value. Equine recombinant growth hormone had no significant effect on the rate of tendon healing, as evaluated sonographically or at necropsy. CONCLUSIONS AND CLINICAL RELEVANCE: As healing developed, alterations in sonographic brightness of injured tendons coincided with real changes in tendon structure. Quantitative sonographic brightness could be used to accurately monitor healing of equine tendon and ligament injuries and investigate the efficacy of various treatment regimens.  相似文献   

4.
OBJECTIVE: To evaluate the effect of recombinant equine growth hormone (rEGH) on the in vitro biomechanical properties of healing superficial digital flexor tendon (SDFT) in horses. STUDY DESIGN: Completely randomized design. SAMPLE POPULATION: Twelve Standardbred horses, 3 to 7 years of age, with ultrasonographically normal forelimb SDFT. METHODS: One week after induction of collagenase (2,000 U) induced superficial flexor tendonitis, horses were randomly divided into groups of 6. One group was administered intramuscular rEGH (10 microg/kg/day for 1 week, then 20 microg/kg/day for 5 weeks), whereas the other group (control subjects) were administered an equivalent volume of saline (0.9% NaCl) solution. At the end of this 6-week treatment, horses were killed and one forelimb SDFT from each horse was harvested for biomechanical testing under uniaxial tension. Results were analyzed using an unpaired Student's t test; significance was set at P 相似文献   

5.
OBJECTIVE: To clone the 5' end of type III collagen and describe its pattern of mRNA and protein expression in normal and healing tendons in horses. ANIMALS: 14 healthy adult horses. PROCEDURE: The tensile region of collagenase-injured superficial digital flexor tendons was harvested at intervals from 1 to 24 weeks after injury. Total RNA was reverse-transcribed into cDNA for cloning and sequencing of type III collagen. Equine-specific nucleic acid probes were developed and used for northern blot analysis and in situ hybridization. Type III collagen protein and cyanogen bromide-cleaved collagen peptides were assessedby gel electrophresis. RESULTS: Type III collagen mRNA expression and protein content increased immediately after injury and remained increased. Type III collagen was localized to the endotenon in normal tendon and in injured tendon at 1 week. At 8 and 24 weeks, expression became more widely distributed throughout the tendon parenchyma. Injured tendon contained 6 times more type I than type III collagen mRNA. Quantities of type III collagen protein were maximal in the first 4 weeks after injury (approx 33%) and then began to decrease. CONCLUSIONS AND CLINICAL RELEVANCE: Type III collagen expression is increased initially in endotenon and subsequently in parenchyma of healing tendon; however, type III remains the minor collagen throughout the healing process. The role of type III collagen in tendon healing is not fully elucidated.  相似文献   

6.
OBJECTIVE: To investigate effects of beta-aminopropionitrile and a combination of insulin-like growth factor (IGF)-I and beta-aminopropionitrile on metabolism of equine tendon fibroblasts. SAMPLE POPULATION: Flexor tendon explants from 3 horses. PROCEDURE: Explants received 1 of 4 treatments (control, IGF-I, beta-aminopropionitrile, and IGF-I/beta-aminopropionitrile) for 10 days, and message expression for collagen types I and III was assessed by use of in situ hybridization. Histologic findings, new protein production, and quantitative determinations of glycosaminoglycan, DNA, and de novo collagen synthesis were made. RESULTS: Insulin-like growth factor-I stimulated an anabolic response in tendon. Collagen synthesis and glycosaminoglycan and DNA content of explants were all increased. Beta-aminopropionitrile significantly suppressed collagen synthesis, which was not ameliorated by concurrent IGF-I treatment. Beta-aminopropionitrile caused alterations in cell morphology characterized by large round cells with eccentric nuclei and decreased density of collagen fibers. Protein production and collagen type-III mRNA expression were reduced in these cells. CONCLUSIONS AND CLINICAL RELEVANCE: Treatment with beta-aminopropionitrile resulted in decreased production of protein and collagen synthesis, which could be expected to suppress tendon healing. The negative effects of beta-aminopropionitrile could not be abrogated by addition of IGF-I to the medium. Treatment resulted in alterations in cell morphology and matrix consistency, which could further delay tendon healing. Beta-aminopropionitrile may impair tendon healing at a cellular level by decreasing collagen production or increasing rate of degradation of existing matrix. Because of reduced crosslinking during beta-aminopropionitrile treatment, in combination with transiently decreased tensile strength, alterations in collagen content and structure may weaken the healing tendon.  相似文献   

7.
OBJECTIVE: To evaluate the effect of recombinant equine growth hormone (rEGH) on the in vitro biomechanical properties of normal adult equine superficial digital flexor tendon (SDFT). STUDY DESIGN: Completely randomized design. SAMPLE POPULATION: Nine Standardbred horses, 6 to 9 years of age with ultrasonographically normal forelimb SDFT. METHODS: Six horses were administered intramuscular (IM) rEGH at 10 microg/kg/day for 1 week, and then 20 microg/kg/day for another 5 weeks; 3 horses (control subjects) were administered an equivalent daily volume of sterile water IM. Horses were killed at the end of the 6-week treatment period, and both forelimb SDFT were harvested and stored at -70 degrees C. In vitro biomechanical testing was performed under uniaxial tension. Results were analyzed using a general linear model of analysis of variance; significance was set at P <.05. RESULTS: There were no differences in cross-sectional area, maximal load at failure, yield load, ultimate and yield tensile strain, ultimate and yield tensile stress, or stiffness between tendons from control and treated horses. CONCLUSIONS: Administration of rEGH to adult Standardbred horses for 6 weeks had no detectable effect on the in vitro biomechanical properties of normal SDFT. CLINICAL RELEVANCE: Administration of rEGH does not modulate the in vitro biomechanical properties of SDFT from adult Standardbred horses.  相似文献   

8.
OBJECTIVE: To determine the amount of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) enzymes induced in vitro in equine alveolar macrophages in response to lipopolysaccharide (LPS). Sample Population-Alveolar macrophages obtained from 12 horses. PROCEDURE: Alveolar macrophages were collected by bronchoalveolar lavage from 12 horses and incubated for 6 hours with LPS (0.001 to 10 microg/ml) or vehicle. Total RNA was extracted and purified. After first-strand cDNA synthesis, mRNA induction was measured, using a polymerase chain reaction (PCR) technique for COX-2, iNOS, and glyceraldehyde 3-phosphate dehydrogenase. In a second study, cells were incubated with LPS or vehicle for 24 hours. Culture medium was assayed for COX-2 and iNOS activity by determining prostaglandin E2 (PGE2) and total nitrite concentrations, respectively. RESULTS: Lipopolysaccharide induces COX-2 and iNOS mRNA in equine alveolar macrophages. Sequencing revealed that PCR products for COX-2 and iNOS had a high degree of nucleotide homology with the human sequences (91% COX-2, 93% iNOS). Production of mRNA for COX-2 and iNOS was accompanied by induction of enzyme activity. Comparing PCR fragment production, expression of mRNA for iNOS appeared to be less than that for COX-2. Induction of COX-2, but not iNOS, was LPS-concentration dependent. Conclusion-Lipopolysaccharide induces COX-2 and iNOS in equine macrophages. CLINICAL RELEVANCE: The induction of iNOS and COX-2 by LPS in equine macrophages suggests these enzymes may be important in the pathophysiology of sepsis. Pharmacologic modulation of iNOS and COX-2 activity may represent a novel therapeutic target in the management of endotoxemia in horses.  相似文献   

9.
The cross-sectional area, collagen content, dry weight as a percentage of the wet weight and the tendon fibre percentage of the cross-sectional area of the equine hindlimb were determined in the superficial and deep digital flexor tendons and the suspensory ligament at 10, 12 and six sites between tarsus and insertion respectively. The values of each of the four parameters varied between different sites in the same tendon, between different tendons within a horse and between analogous tendons of different horses. Within a tendon the cross-sectional area was inversely proportional to the collagen content, the dry weight and the tendon fibre percentage. Within a horse and between different horses the cross-sectional area of a tendon was inversely proportional to the collagen content and the dry weight percentage. It was concluded that the cross-sectional area is not representative of the strength of an equine tendon.  相似文献   

10.
IgE is the dominant immunoglobulin isotype involved in type I hypersensitivities in mammals. The heavy chain constant region domains of equine IgE are encoded by a single gene, the Cvarepsilon gene. By restriction analysis of cDNA from 15 unrelated horses, we have now identified two Cvarepsilon alleles, characterised by a Sma I restriction fragment length polymorphism, which we designated Cvarepsilon(a) and Cvarepsilon(b). Sequence analysis of both, Cvarepsilon(a) and Cvarepsilon(b) cDNA, showed in addition two single base exchanges resulting in two amino acid substitutions. Both sequences have only 95.9% homology of the coding region sequence with the published equine Cvarepsilon sequence, which could represent a third haplotype. Polymorphism of the IgE heavy chain constant region gene, as described here, might well impose genetic variability on the effector functions of equine IgE predisposition to allergic diseases in horses.  相似文献   

11.
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12.
Normal and diseased superficial digital flexor tendons at different stages of healing from seven Thoroughbred horses, aged 3–6 years, were evaluated by correlation of gray scale histogram analysis of tendon cross-sectional ultrasonograms with histopathologic examination. Normal tendon and tendons at different stages of healing, excluding acute tear stage, were characterized by normally distributed histogram patterns. The histogram mean value of normal tendons was higher than the corresponding values in diseased tendons at different stages of healing (p < 0.01). In addition, the histogram mean of acute lesions was lower than for early fibrosis or healed lesions (p < 0.01). The histogram mean increased as healing progressed. The results show that gray scale histogram analysis of tendon ultrasonogram can be used to distinguish between normal and abnormal superficial digital flexor tendon in racing horses.  相似文献   

13.
OBJECTIVE: To describe a method to calculate flexor tendon forces on the basis of inverse dynamic analysis and an in vitro model of the equine forelimb and to quantify parameters for the model. SAMPLE POPULATION: 38 forelimbs of 23 horses that each had an estimated body mass of > or = 500 kg. PROCEDURE: Longitudinal limb sections were used to determine the lines of action of the tendons. Additionally, limb and tendon loading experiments were performed to determine mechanical properties of the flexor tendons. RESULTS: The study quantified the parameters for a pulley model to describe the lines of action. Furthermore, relationships between force and strain of the flexor tendons and between fetlock joint angle and suspensory ligament strain were determined, and the ultimate strength of the tendons was measured. CONCLUSION AND CLINICAL RELEVANCE: The model enables noninvasive determination of forces in the suspensory ligament, superficial digital flexor tendon, and distal part of the deep digital flexor (DDF) tendon. In addition, it provides a noninvasive measure of loading of the accessory ligament of the DDF tendon for within-subject comparisons. However, before application, the method should be validated. The model could become an important tool for use in research of the cause, prevention, and treatment of tendon injuries in horses.  相似文献   

14.
OBJECTIVE: To test the sensitivity to measurement and modeling errors of a method for noninvasive calculation of flexor tendon forces in the equine forelimb and to calculate tendon forces for Dutch Warmblood horses during trotting. SAMPLE POPULATION: A normative set of kinematic and ground-reaction force (GRF) data obtained from horses during trotting in another study. PROCEDURE: Forces in the flexor tendons were calculated from the data set before and after addition of fixed relative and absolute errors. Amount of error was based on normal accuracy of the variables. A similar analysis was performed for a measure of strain of the accessory ligament of the deep digital flexor tendon. RESULTS: The only errors that had a substantial influence on accuracy were modeling errors in the mechanical properties of the suspensory ligament and measurement errors in the point of application of the GRF and position of the marker on the distal interphalangeal joint. Influence of the measurement errors could be minimized by applying usual correction methods. CONCLUSIONS AND CLINICAL RELEVANCE: After correction of measurement errors, the method can be used to calculate mean tendon forces for a group of horses and to evaluate the influence of factors such as surface properties, type of shoe, speed, and fatigue on tendon forces. The method could become an important tool for use in research on the cause, prevention, and treatment of tendon injuries in horses.  相似文献   

15.
AIM: To determine the effect of polyester (terylene) fibre implants on normal equine superficial digital flexor (SDF) tendon structure. METHODS: Normal forelimb SDF tendons (n=24) of 12 horses were divided into unoperated, sham-operated, and implanted (terylene fibre implant) groups. Horses were assessed for lameness and ultrasonographic changes to SDF tendons at intervals up to 48 weeks post-operatively. After euthanasia, SDF tendons were collected for histological and ultrastructural examination. Histological sections were examined for alcian blue staining intensity, cellularity, fibril bundle alignment, fascicle separation and crimp morphology. Mass-average diameters (MADs) of collagen fibrils were calculated from electron micrographs and compared between treatment groups. RESULTS: Insertion of terylene fibre implants resulted in short-term (8 weeks) lameness in implanted limbs. Ultrasonographically, the implants could be detected in 50% of implanted tendons, but were associated with tendon swelling and the presence of hypoechoic core lesions in 7/8 implanted limbs. There were significant alterations in alcian blue staining, cellularity and crimp morphology in the central fascicles of sham-operated and implanted tendons, and alteration in fibril alignment in the central fascicles of implanted tendons. Unoperated tendons remained histologically normal. MADs of collagen fibrils did not differ between sham-operated, implanted and unoperated limbs. CONCLUSIONS: Both the sham procedure and the insertion of terylene fibre implants led to alterations in tendon structure that persisted for up to 48 weeks. Persistence of disorganised connective tissue at the proximal and distal ends of the terylene fibre implants may predispose implanted tendons to continued risk of injury. CLINICAL RELEVANCE: It is unlikely that terylene fibre implants offer any advantage over standard non-surgical treatments for mild to moderate cases of SDF tendonitis in the horse.  相似文献   

16.
Background: Characterization of anemia in horses presents a challenge, as they do not release reticulocytes into peripheral blood. Transferrin receptor (TfR) expression is highest on erythroid cells in people and rats, and measurement of a soluble serum form (sTfR) is used to quantify erythropoiesis in these species. We hypothesized that equine TfR (eTfR) expression is similar in quantity and distribution to that in these other species and thus has potential for characterization of the regenerative response in anemic horses. Objective: This study was conducted to clone and sequence the eTfR gene and measure expression levels using quantitative real‐time PCR and immunohistochemical (IHC) staining. Methods: Total RNA from equine bone marrow was used to produce cDNA. The eTfR gene was amplified using pooled gene‐specific primers, and PCR products were sequenced. Rapid amplification of cDNA ends was used to obtain the first 22 nucleotides of the coding sequence. Quantitative PCR was performed using eTfR gene‐specific primers, and IHC staining was used to localize TfR protein expression. Results: The deduced amino acid (aa) sequence (767 aa) of the eTfR was 75–83% identical with sequences of the receptor in several other mammals. As in people and rats, eTfR mRNA expression was highest in the bone marrow, and distribution in other tissues was also similar. Conclusion: The eTfR gene is similar to that of other mammals in structure and expression levels. We hypothesize that it is also similar in function and that, following development of an immunoassay, determining sTfR concentrations will be useful for identifying the regenerative response in anemic horses.  相似文献   

17.
Specific tendons show a high incidence of partial central core rupture which is preceded by degeneration. In the performance horse, the superficial digital flexor tendon (SDFT) is most often affected. We have described previously the molecular changes that are associated with degeneration in the central core region of the equine SDFT. The pathophysiological mechanism leading to change in synthetic activity of central zone cells in degenerated tendons is not known. In this study, we test the hypothesis that ageing results in matrix composition changes within the central zone of the SDFT. Extracellular matrix composition and cellularity were analysed in equine SDFTs collected from Thoroughbred horses and compared with a flexor tendon which rarely shows degenerative change and subsequent injury (deep digital flexor tendon, DDFT). Data were examined for age-related changes to central and peripheral zone tissue of the SDFT and DDFT. Ageing in both tendons (SDFT and DDFT) resulted in a significant increase in collagen-linked fluorescence and a decrease in cellularity in the DDFT but not the SDFT. The central zone tissue from the SDFT had a significantly higher proportion of type III collagen than the peripheral zone of the tendon. The highest level of type III collagen was found in the central zone tissue of the SDFT from the older group of horses and this may represent the early stages of a degenerative change. Collagen content did not differ between the 2 flexor tendons; however, there were differences in collagen type and organisation. The SDFT had a higher type III collagen content, higher levels of the mature trifunctional collagen crosslink hydroxylysylpyridinoline, lower total chondroitin sulphate equivalent glycosaminoglycan content, smaller diameter collagen fibrils and a higher cellularity than the DDFT. In conclusion, differences in macromolecular composition exist between the flexor tendons and ageing contributes to a tendon specific change in composition.  相似文献   

18.
OBJECTIVE: To test the failure strength and energy of 2 bioabsorbable implants applied to transected deep digital flexor tendons (DDFT) from adult horses. STUDY DESIGN: Ex vivo biomechanical experiment. SAMPLE POPULATION: Twelve pairs of deep digital flexor tendons harvested from the forelimbs of fresh equine cadavers. METHODS: Poly-L-lactic acid tendon plates were custom manufactured for application to the cylindrical surface of an adult equine deep digital flexor tendon. Twelve pairs of DDFTs were transected 2 cm distal to the insertion of the distal check ligament of the deep digital flexor tendon. One tendon of each pair was randomly selected for repair with a biodegradable plate or a 3-loop pulley method. Size 2 polydioxanone suture was used in both repairs. Repairs were tested in tension to failure, with peak force (PF) and total energy (TE) at repair failure recorded in Newtons (N) and Joules (J), respectively. A paired t-test was used for statistical evaluation with a significant level set at P< or = .05. RESULTS: Mean+/-SD PF for failure of plated tendons (1507.08+/-184.34 N) was significantly greater than for sutured tendons (460.86+/-60.93 N). TE was also significantly greater for failure of plated tendons versus sutured tendons. CONCLUSIONS: Plate fixation of transected cadaver DDFTs appear to have superior immediate failure strength than 3-loop pulley repairs. CLINICAL RELEVANCE: Whereas in vivo testing is required, a bioabsorbable tendon plate may provide initial increased strength to support tendon healing and decrease external coaptation requirements.  相似文献   

19.
In this study antemortem evaluation of equine flexor tendons--the superficial digital flexor tendon and the deep digital flexor tendon--using magnetic resonance (MR) images was performed. Postmortem flexor tendons were used to prepare the slice positions, coil and body positions for MR imaging. It was possible by this method to take antemortem MR images of equine limbs that distinguished features as well as postmortem images described in previous studies. The total time of antemortem scanning was about 40 min. This study is the first to report antemortem MR images in horses.  相似文献   

20.
OBJECTIVE: To correlate quantitative analysis of ultrasonographic images of normal (injury-free) equine superficial digital flexor (SDF) tendons and equine SFD tendons that have pathologic changes with corresponding histologic sections. SAMPLE POPULATION: 4 SDF tendons, 2 of which had various stages of tissue integrity. The 2 ipsilateral tendons were used as points of reference. PROCEDURE: Tendons were mounted in a custom-made device that permitted sequential scanning, transversely and perpendicular to the tendon long axis. At precise steps of 0.5 mm, transverse ultrasonographic images were collected. Subsequently, tendons were fixed and prepared for histologic examination. The following 8 tissue types were discerned: normal young, normal old, necrotic, early granulation, late granulation, early fibrotic, late fibrotic, and scar tissues. In areas of interest, the corresponding ultrasonographic images were selected for gray level statistical analysis. RESULTS: Compared with other tissue types, early-stage granulation tissue was characterized by substantially lower mean gray level and a clearly different histogram. Necrotic tissue had a higher mean gray level, with a virtually normal histogram. In late granulation and early fibrotic tissues, the mean gray level and the histogram could not be discerned from those of normal tendon tissue. The same applied to late fibrotic and scar tissues; mean gray levels were fractionally lower than those of normal tendon tissue with a completely normal histogram. CONCLUSIONS: Although quantification of the transverse ultrasonographic image by use of first-order gray level statistics may be helpful, the method is not sufficiently sensitive to accurately and unequivocally determine the type of tendon tissue. Quantitative analysis should incorporate transverse and longitudinal information.  相似文献   

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