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1.
Can J Surg ; 51(3): 167-72, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18682794

RESUMO

BACKGROUND: Denervation substantially impairs healing of the medial collateral ligament (MCL). Because normal ligaments are sparsely innervated, we hypothesized that neuropeptide-containing neurons would sprout or proliferate after ligament transection, followed by later regression with healing, in a manner analogous to blood vessels. METHODS: We transected the right MCL in 9 mature female New Zealand white rabbits and killed 3 rabbits at 2, 6 or 14 weeks. Alternate sets of 12-mm serial sections of healing MCL scars were examined by fluorescent immunohistochemistry for substance P (SP), calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY) and pan-neuronal marker PGP9.5. RESULTS: Normal MCLs had few peptidergic fibres located in the epiligament in a perivascular pattern. At 2 weeks, PGP9.5-, SP-and CGRP-positive fibres had increased in the epiligament adjacent to the injury. By 6 weeks, there were increases in CGRP-and PGP9.5-positive fibres in epiligament and scar, with similar but less marked increases in SP-positive fibres. At 14 weeks, there was notable regression of immunostained peptidergic nerve fibres in the scar. CONCLUSION: This experiment shows evidence for a remarkable plasticity of ligament innervation after injury, supporting the idea that neuronal factors play a fundamental role in wound healing.


Assuntos
Ligamento Colateral Médio do Joelho/lesões , Ligamento Colateral Médio do Joelho/inervação , Cicatrização/fisiologia , Animais , Peptídeo Relacionado com Gene de Calcitonina/metabolismo , Feminino , Imuno-Histoquímica , Ligamento Colateral Médio do Joelho/metabolismo , Plasticidade Neuronal , Neuropeptídeo Y/metabolismo , Coelhos , Substância P/metabolismo , Ubiquitina Tiolesterase/metabolismo
2.
Am J Sports Med ; 36(7): 1337-46, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18448582

RESUMO

BACKGROUND: The drastic difference in healing capacity between the anterior cruciate ligament and the medial collateral ligament is still largely unexplained. Few studies have compared the profiles of messenger ribonucleic acid expression for healing-associated molecules in ligaments during the course of healing. HYPOTHESIS: Injury responses of the injured anterior cruciate ligament and medial collateral ligament are characterized by very different profiles of angiogenesis-promoting and repair-associated gene expression during the healing process. STUDY DESIGN: Controlled laboratory study. METHODS: Reverse-transcriptase polymerase chain reaction was used to assay expression of messenger ribonucleic acid for 11 healing- and angiogenesis-associated molecules at 3 days and 2, 6, and 16 weeks after anterior cruciate ligament or medial collateral ligament injury in adult female New Zealand White rabbits. RESULTS: Marked differences were found in the postinjury changes in messenger ribonucleic acid levels in the anterior cruciate ligament compared to the medial collateral ligament. Notably, messenger ribonucleic acid levels for the important repair-associated growth factor transforming growth factor-beta1 did not increase in injured anterior cruciate ligament at any time point. Similarly, unlike the injured medial collateral ligament, no statistically significant increases in messenger ribonucleic acid levels for the important scar matrix protein collagen III were detected in injured anterior cruciate ligament. In contrast, matrix metalloproteinase messenger ribonucleic acid levels were markedly elevated in injured anterior cruciate ligament but only modestly increased in medial collateral ligament. CONCLUSION: The results suggest that injury leads to an antifibrotic, catabolic response in the rabbit anterior cruciate ligament, possibly to prevent fibrosis and diminish the risk for loss of joint motion. CLINICAL RELEVANCE: The development of effective biologically based treatments for anterior cruciate ligament injuries will need to incorporate strategies to deal with the significant differences in the molecular responses to injury of these tissues.


Assuntos
Lesões do Ligamento Cruzado Anterior , Ligamento Cruzado Anterior/fisiopatologia , Ligamento Colateral Médio do Joelho/lesões , Ligamento Colateral Médio do Joelho/fisiopatologia , Neovascularização Fisiológica/genética , RNA Mensageiro/genética , Cicatrização/genética , Animais , Ligamento Cruzado Anterior/irrigação sanguínea , Colágeno Tipo I/genética , Colágeno Tipo III/genética , Feminino , Linfotoxina-alfa/genética , Metaloproteinases da Matriz Secretadas/genética , Ligamento Colateral Médio do Joelho/irrigação sanguínea , Fator de Crescimento Neural/genética , Coelhos , Trombospondina 1/genética , Inibidores Teciduais de Metaloproteinases/genética , Ativador de Plasminogênio Tipo Uroquinase/genética , Fator A de Crescimento do Endotélio Vascular/genética
3.
J Orthop Res ; 26(7): 957-64, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18302239

RESUMO

Previous work has shown that innervation participates in normal ligament healing. The present study was performed to determine if exogenous nerve growth factor (NGF) would improve the healing of injured ligament by promoting reinnervation, blood flow, and angiogenesis. Two groups of 30 Sprague-Dawley rats underwent unilateral medial collateral ligament transection (MCL). One group was given 10 microg NGF and the other was given PBS via osmotic pump over 7 days after injury. After 7, 14, and 42 days, in vivo blood flow was measured using laser speckle perfusion imaging (LSPI). Morphologic assessments of nerve density, vascularity, and angiogenesis inhibitor production were done in three animals at each time point by immunohistochemical staining for the pan-neuronal marker PGP9.5, the endothelial marker vWF, and the angiogenesis inhibitor thrombospondin-2 (TSP-2). Ligament scar material and structural mechanical properties were assessed in seven rats at each time point. Increased nerve density was promoted by NGF at both 14 and 42 days. Exposure to NGF also led to increased ligament vascularity, as measured by histologic assessment of vWF immunohistochemistry, although LSPI-measured blood flow was not significantly different from controls. NGF treatment also led to decreased expression of TSP-2 at 14 days. Mechanical testing revealed that exposure to NGF increased failure load by 40%, ultimate tensile strength by 55%, and stiffness by 30% at 42 days. There were no detectable differences between groups in creep properties. The results suggest that local application of NGF can improve ligament healing by promoting both reinnervation and angiogenesis, and results in scars with enhanced mechanical properties.


Assuntos
Ligamento Colateral Médio do Joelho/lesões , Neovascularização Fisiológica/efeitos dos fármacos , Fator de Crescimento Neural/farmacologia , Neurônios/efeitos dos fármacos , Cicatrização/efeitos dos fármacos , Animais , Fenômenos Biomecânicos , Cicatriz/tratamento farmacológico , Imuno-Histoquímica , Masculino , Ligamento Colateral Médio do Joelho/irrigação sanguínea , Ligamento Colateral Médio do Joelho/inervação , Ligamento Colateral Médio do Joelho/fisiologia , Fator de Crescimento Neural/uso terapêutico , Ratos , Ratos Sprague-Dawley , Fluxo Sanguíneo Regional/efeitos dos fármacos
4.
Can J Surg ; 50(2): 96-100, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17550711

RESUMO

OBJECTIVE: The purpose of this prospective study was to determine the positive predictive value (PPV) of the point of maximal posterior joint line tenderness (JLT), as a clinical sign, to diagnose underlying meniscal tears. METHODS: We conducted a prospective study of patients requiring arthroscopic surgery, who consecutively presented to the University of Calgary's Sport Medicine Centre. The femurotibial joint line was palpated for the point of maximal tenderness. We recorded the data on the arthroscopy report. A second examiner (orthopedic sport medicine surgical fellow or sport medicine physician) performed the same protocol. An arthroscopist documented the site of pathology as detected by arthroscopy. RESULTS: We found a PPV of 60.0% and a negative predictive value of 62.5%, suggesting that maximal posterior JLT may be predictive of meniscal pathology. The sensitivity and specificity were 84.6% and 31.2%, respectively (p = 0.155), with Fisher's exact test. The kappa score assessed interobserver reliability and was good at 0.48. Patients with maximal posterior JLT but no meniscal pathology did have other confounding pathology and patients with no maximal posterior JLT who had meniscal pathology usually had confounding knee pathology. CONCLUSIONS: We found a PPV of 60.0% of maximal posterior JLT and meniscal pathology located at the same anatomical site on arthroscopic examination.


Assuntos
Artralgia , Traumatismos do Joelho/diagnóstico , Palpação , Lesões do Menisco Tibial , Adulto , Idoso , Artroscopia , Feminino , Humanos , Traumatismos do Joelho/cirurgia , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Valor Preditivo dos Testes , Reprodutibilidade dos Testes
5.
J Orthop Res ; 24(9): 1842-53, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16865716

RESUMO

Previous experiments revealed that denervation impairs healing of the MCL. This suggested the hypothesis that denervation would decrease repair-associated mRNA levels in the injured MCL when compared with normally innervated injured MCL. Adult, skeletally mature female rabbits were assigned to one of four groups: unoperated control, femoral nerve transection alone (denervated controls), MCL partial tear or denervated MCL partial tear. At three days, two weeks, six weeks or sixteen weeks post-surgery, cohorts of 6 rabbits from each experimental group were killed. Ligaments were harvested, RNA extracted and RT-PCR was performed using rabbitspecific primers. In the denervated injury group, mRNA levels for the angiogenesis-associated gene MMP-13, matrix components Collagen I and III, growth factor TGF-beta and angiogenesis inhibitors TIMP-3, and TSP-1 had all increased by two-weeks post-injury, in comparison to the non-denervated injury group (p < or = 0.01). An increased level of TSP-1 mRNA was also detected in the denervated injured group at sixteen weeks post injury (p < or = 0.01). Contrary to the initial hypothesis, denervation led to increased mRNA levels for many relevant molecules during the early stages of MCL healing. Thus, inappropriate timing of over-expression of some molecules may potentially contribute to the decreased quality of the scar tissue, particularly molecules such as TSP-1. Neuronal derived factors strongly influence the in vivo metabolic activity of ligament and scar fibroblasts in the initial phases of healing.


Assuntos
Traumatismos do Joelho/metabolismo , Ligamento Colateral Médio do Joelho/inervação , Ligamento Colateral Médio do Joelho/metabolismo , RNA Mensageiro/metabolismo , Cicatrização/fisiologia , Animais , Cicatriz/genética , Cicatriz/metabolismo , Colágeno/genética , Colágeno/metabolismo , Denervação , Feminino , Nervo Femoral/cirurgia , Regulação da Expressão Gênica/genética , Regulação da Expressão Gênica/fisiologia , Metaloproteinases da Matriz/genética , Metaloproteinases da Matriz/metabolismo , Ligamento Colateral Médio do Joelho/lesões , Modelos Animais , Fator de Crescimento Neural/genética , Fator de Crescimento Neural/metabolismo , RNA Mensageiro/genética , Coelhos , Trombospondina 1/genética , Trombospondina 1/metabolismo , Inibidor Tecidual de Metaloproteinase-1/genética , Inibidor Tecidual de Metaloproteinase-1/metabolismo , Inibidor Tecidual de Metaloproteinase-3/genética , Inibidor Tecidual de Metaloproteinase-3/metabolismo , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/metabolismo , Fator de Crescimento Transformador beta1 , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo
6.
Biochem J ; 388(Pt 2): 501-8, 2005 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-15679468

RESUMO

XOR (xanthine oxidoreductase) purified from human milk was shown to contain 0.04 atom of Mo and 0.09 molecule of molybdopterin/subunit. On the basis of UV/visible and CD spectra, the human enzyme was approx. 30% deficient in iron-sulphur centres. Mo(V) EPR showed the presence of a weak rapid signal corresponding to the enzyme of low xanthine oxidase activity and a slow signal indicating a significant content of desulpho-form. Resulphuration experiments, together with calculations based on enzymic activity and Mo content, led to an estimate of 50-60% desulpho-form. Fe/S EPR showed, in addition to the well-known Fe/S I and Fe/S II species, the presence of a third Fe/S signal, named Fe/S III, which appears to replace partially Fe/S I. Comparison is made with similarly prepared bovine milk XOR, which has approx. 15-fold higher enzymic activity and Mo content. Taken along with evidence of low Mo content in the milk of other mammals, these findings add further support to the idea that XOR protein plays a physiological role in milk (e.g. in secretion) equal in importance to its catalytic function as an enzyme.


Assuntos
Ferro/análise , Molibdênio/análise , Enxofre/análise , Xantina Desidrogenase/química , Animais , Bovinos , Coenzimas , Feminino , Humanos , Metaloproteínas , Leite/enzimologia , Cofatores de Molibdênio , Compostos Organometálicos/química , Pteridinas/química , Análise Espectral , Xantina Desidrogenase/metabolismo
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