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PubMed1995

Age-dependent changes in proteoglycan biosynthesis in human intervertebral discs.

Proteoglycans from annulus fibrosus and nucleus pulposus of human intervertebral disc were investigated by electrophoresis in a composite agarose-polyacrylamide gel and immunohistochemically using various monoclonal antibodies against components of extracellular matrix. There were at least five different populations of proteoglycans in both annulus fibrosus and nucleus pulposus. Proteoglycans represented by individual electrophoretic bands differed from each other in hydrodynamic size but all of them contained epitopes present in keratan sulphate. Chondroitin sulphate could be detected in populations with molecular weight above 200,000 daltons. We could postulate that the cleavage of proteoglycan chains starts at the C-terminal end. This is supported by the finding that the globular region G2 on the protein core was detected in the same populations as keratan sulphate. We could confirm these results using tissue cultures of nucleus pulposus, inner and external part of annulus fibrosus. Of interest is the finding that there is de novo synthesis of globular domain G1 only in structures of intervertebral disc from a 16-year-old male and not in the tissue of a 69-year-old male. This might contribute to an explanation of decreased aggregation of proteoglycans during the aging process.

Adolescent↗
PubMed2002

Effect of tail suspension (or simulated weightlessness) on the lumbar intervertebral disc: study of proteoglycans and collagen.

STUDY DESIGN: An experiment to measure the proteoglycan and collagen content of the lumbar intervertebral discs of rats that had been tail-suspended for up to 4 weeks. OBJECTIVES: To determine the effect of tensile force (or simulated weightlessness) on the intervertebral disc. SUMMARY OF BACKGROUND DATA: During space flight the intervertebral disc experiences low compressive force (because of so-called "weightlessness"), which, in turn, produces, among other things, low hydrostatic pressure acting on the disc cells. Although disc cells respond (in vitro) to changes in hydrostatic pressure, it is unclear what effect low levels of hydrostatic pressure have in vivo and whether they lead to a degenerative catabolic process. The rat tail-suspension model is appropriate for studying the effects of tensile force on the disc. The disc (especially the anulus) is subjected to tension during various body movements (e.g., bending stretches the posterior anulus, and twisting tensions the whole anulus). METHODS: Thirty-two Sprague-Dawley rats were tail-suspended for either 2 weeks (16 rats) or 4 weeks (16 rats). Sixteen other rats were left unsuspended for 4 weeks; these were used as controls. At the end of 2 or 4 weeks, as appropriate, the rats were killed and their lumbar spines were removed. In each rat the six lumbar discs were bisected and the discs (anulus and nucleus together) were carefully removed. The six lumbar discs from one rat were pooled with the six lumbar discs of a second matching rat (i.e., from the same group) to give one sample. The disc samples were then assessed using enzyme-linked immunosorbent assays. RESULTS: There was a 35% statistically significant decrease in proteoglycan content going from the control group down to the 4-week group, but no significant differences between the control group and the 2-week group or between the 2-week group and the 4-week group. There were no statistically significant differences between the three groups for collagen I or collagen II. CONCLUSIONS: These findings clearly establish a link between decreased proteoglycan content and tension on the disc, as modeled by the tail-suspended rat.

Animals↗
PubMed1994

In vivo diurnal variation in intervertebral disc volume and morphology.

STUDY DESIGN: Three-dimensional reconstructions of MRI scans measured volume, height, and diameter of intervertebral discs. These measurements were made in vivo. OBJECTIVES: This study documented diurnal change in lumbar disc volume and morphology. The authors studied the pattern of this change over the disc levels that were examined and documented individual differences. SUMMARY OF BACKGROUND DATA: There is a diurnal pattern of standing heights. The majority of this diurnal height change can be accounted for by height loss within the intervertebral disc, which bulges radially with loading. These studies have been performed in vivo. METHODS: Eight normal males were studied using two protocols. In one, the volunteers were in the supine position for 6 hours before MRI scanning. In the other, volunteers spent 4 hours standing and 3 hours sitting before MRI scanning. Three-dimensional MRI scanning was carried out on the L3-4, L4-5, and L5-S1 discs. RESULTS: Volume height and AP diameter of the lumbar intervertebral discs decreased significantly after the protocol of a day's activity. The mean decrease in disc volume at the L3-4 level after standing was 21.1%. At the L4-5 level, it decreased a mean of 18.7%, whereas at the L5-S1 level, there was a 21.6% mean decrease. CONCLUSIONS: The mean simulated diurnal volume decrease in the lower three lumbar discs is 16.2%. Most of the diurnal loss in disc height is due to volume loss. The effect of radial bulging is minimal.

Adult↗
PubMed1999

Heights of the lumbar intervertebral discs related to age in Turkish individuals.

The present study investigated the changes in the heights and anteroposterior diameters of human intervertebral discs by means of measurements from radiographs, to determine age changes of lumbar intervertebral discs in Turkish people. Measurements of anterior and posterior disc heights and disc depths were made for 200 clinic subjects of different age groups from lateral radiographs. The height of the intervertebral disc increases with aging only in males and the disc depth in both sexes. Our findings generally corroborate previous studies. It is suggested that the different findings from the present study might be peculiar to the society.

Adolescent↗
PubMed2004

Animal models of intervertebral disc degeneration: lessons learned.

STUDY DESIGN: A literature review of intervertebral disc degeneration animal models. OBJECTIVES: Focus is placed on those models that suggest degeneration mechanisms relevant to human. SUMMARY OF BACKGROUND DATA: Medical knowledge from observational epidemiology and intervention studies suggest many etiologic causal factors in humans. Animal models can provide basic science data that support biologic plausibility as well as temporality, specificity, and dose-response relationships. METHODS: Studies are classified as either experimentally induced or spontaneous, where experimentally induced models are subdivided as mechanical (alteration of the magnitude or distribution of forces on the normal joint) or structural (injury or chemical alteration). Spontaneous models include those animals that naturally develop degenerative disc disease. RESULTS: Mechanobiologic relationships are apparent as stress redistribution secondary to nuclear depressurization (by injury or chemical means) can cause cellular metaplasia, tissue remodeling, and pro-inflammatory factor production. Moderate perturbations can be compensated for by cell proliferation and matrix synthesis, whereas severe perturbations cause architectural changes consistent with human disc degeneration. CONCLUSIONS: These models suggest that two stages of architectural remodeling exist in humans: early adaptation to gravity loading, followed by healing meant to reestablish biomechanical stability that is slowed by tissue avascularity. Current animal models are limited by an incomplete set of initiators and outcomes that are only indirectly related to important clinical factors (pain and disability).

Animals↗
PubMed1993

Mechanosensitive afferent units in the lumbar intervertebral disc and adjacent muscle.

The purpose of this study was to characterize the somatosensory units of the lumbar intervertebral disc and adjacent muscle. A laminectomy was performed on the lumbar spine of adult male Japanese White rabbits. Receptive fields of mechanosensitive afferent units were investigated in the intervertebral disc and adjacent muscle, and electrophysiologic recordings were obtained from filaments of the dorsal root. Thirteen mechanosensitive units were identified: three units in the intervertebral disc area, and 10 units in the psoas muscle. Of the three units in the disc area, one was identified at the surface of the L5-6 anulus fibrosus and two at the insertion of the anulus fibrosus to the L5 and L6 vertebral bodies. These three units belonged to Group III and had very high mechanical thresholds, more than 160 g. The 10 units in the psoas muscle belonged to Groups II, III, and IV, and had mechanical thresholds ranging from 0.22 to 12.6 g. The units in the disc area may serve as nociceptors sensitive to strong noxious stimulation that could traumatize the tissue. The units in the psoas muscle may contribute to nociception and proprioception.

Animals↗
PubMed1995

Mechanoreceptors in intervertebral discs. Morphology, distribution, and neuropeptides.

STUDY DESIGN: The present study investigated the occurrence and morphology of mechanoreceptors in human and bovine intervertebral discs and longitudinal ligaments. OBJECTIVE: To determine the type and frequency of mechanoreceptors present in intervertebral discs and anterior longitudinal ligaments in two patient groups, those with low back pain and those with scoliosis. Bovine coccygeal discs were examined. SUMMARY OF BACKGROUND DATA: Nerves have been described in intervertebral tissues, but there is little information on the endings of these nerves and their receptors, stimulation of which can cause a nerve impulse. METHODS: The presence of mechanoreceptors were investigated by immunolocalization of nerves and neuropeptides. By examining sequential sections, the frequency of receptors was assessed. RESULTS: Immunoreactivity to neural antigens showed mechanoreceptors in the anulus fibrosus and longitudinal ligaments of bovine and human specimens. Their morphology resembled Pacinian corpuscles, Ruffini endings, and, most frequently, Golgi tendon organs. They were found in 50% of discs investigated from patients with low back pain and in 15% of those with scoliosis. CONCLUSIONS: Mechanoreceptors were found in the outer 2-3 lamellae of the human intervertebral disc and anterior longitudinal ligament. Physiologic studies in other tissues indicate that these provide the individual with sensation of posture and movement, and in the case of Golgi tendon organs, of nociception. In addition to providing proprioception, mechanoreceptors are thought to have roles in maintaining muscle tone and reflexes. Their presence in the intervertebral disc and longitudinal ligament can have physiologic and clinical implications.

Adolescent↗
PubMed1990

[Epiduralography for diagnosis of lumbar intervertebral disc protrusion: report of 304 cases].

The authors used epiduralography in 304 cases for the diagnosis of lumbar intervertebral disc protrusion. The radiopaque contrast media was injected into the epidural space and then X-rays were taken of the 304 cases, 273 cases received surgical intervention. Two hundred and seventy positive epidural X-ray, all were confirmed to have protruded or ruptured intervertebral disc at surgery. Three cases had negative epiduralgram preoperatively, no disc protrusion revealed at operation. Thus the accuracy of this technique in diagnosis of intervertebral disc protrusion was L 100%. The findings of positive epidural X-ray may be classified into 5 categories: (1) Lateral filling defect (21.2%), (2) Irregular filling defect near the center (0.7%), (3) Complete block of epidural space (35.6%), (4) Incomplete block of epidural space (27.4%), and (5) Unilateral block of epidural space (15.1%).

Humans↗
PubMed1986

Effects of collagenase and chymopapain on spinal nerves and intervertebral discs of cynomolgus monkeys.

In order to test the safety and efficacy of Nucleolysin, a collagenase for intradiscal chemotherapy, laminectomies were performed on the L2-3 intervertebral discs of four groups of three young adult Cynomolgus monkeys. One primate from each group was injected with half the recommended human dose of Nucleolysin, chymopapain, or the same volume of sterile water. The remaining half of the human dose of each drug or equal volume of sterile water was equally divided and placed upon the right L-3 and L-4 nerve roots at their vertebral foramina. The right L-4 nerve root was first compressed for 10 seconds with an aneurysm clip. These procedures were done to simulate inadvertent contact of enzyme with spinal nerves in patients undergoing chemonucleolysis. After 4 weeks of observation, the 12 primates were humanely killed and examined post mortem. The effects of both enzymes were limited to those tissues with which they came in direct contact. Complete digestion of the nucleus pulposus of all enzyme-injected intervertebral discs was observed. Variable portions of the anulus fibrosus (from 2.3% to 57.4%) were also dissolved. Direct contact of Nucleolysin with lumbar nerve roots caused minor perineural reaction and no more intraneural changes than seen in sterile water controls. Chymopapain induced mild to severe perineural skeletal muscle necrosis and fibrosis with perineural arterial lesions as well as a degenerative neuropathy which was more marked in the traumatized nerve. The results of this study suggest that Nucleolysin and chymopapain are approximately equally effective on intervertebral discs, and that Nucleolysin is less injurious to spinal nerve roots and perineural tissue at the doses used.

Animals↗
PubMed2004

In vivo bioluminescent imaging of virus-mediated gene transfer and transduced cell transplantation in the intervertebral disc.

STUDY DESIGN: Work presented here used a small animal model to demonstrate the feasibility and usefulness of in vivo bioluminescent imaging to studying degenerative disc disease. OBJECTIVES: To determine the utility of in vivo bioluminescent imaging to monitor the temporal and spatial expression of genetically modified cells within the intervertebral disc of a rodent model. SUMMARY OF THE BACKGROUND DATA: Noninvasive imaging of genetically engineered cells in the spine has the advantage of allowing events to be tracked without killing the animal and can be used to follow the time course of a particular therapy. Results are presented on the use of Sprague-Dawley rats in experimental studies in which the luciferase reporter gene was delivered to the lumbar intervertebral disc through adenovirus-mediated or cell-based transfer techniques to demonstrate the feasibility to monitor gene expression noninvasively over time. METHODS: Tissue culture, disc surgery, and in vivo bioluminescent imaging were used. The intervertebral disc of the rat was either injected in situ with an adenovirus containing the luciferase reporter gene or implanted with fat, bone marrow or intervertebral disc cells transduced ex vivo and contained in a bioresorbable carrier. Results were assessed with in vivo bioluminescent imaging at several time points. CONCLUSION: Data from 11 animals were obtained with imaging up to 14 days. To our knowledge, this is the first description of in vivo bioluminescence imaging to study spinal conditions. We have characterized the relative expression of three cell types transduced with the Ad-luc virus by ex vivo transfection followed by cell implantation in the rat spine and compared them to one another and to direct infection of Ad-luc adenovirus in situ. Our results demonstrate the feasibility of tracing genetically altered cells in the spine. This technique has the potential to be used to noninvasively track the fate and expression of therapeutic genes within the spine of small animals used in disc research.

Adenoviridae↗
PubMed1999

Compression-induced changes in intervertebral disc properties in a rat tail model.

STUDY DESIGN: An Ilizarov-type apparatus was applied to the tails of rats to assess the influence of immobilization, chronically applied compression, and sham intervention on intervertebral discs of mature rats. OBJECTIVES: To test the hypothesis that chronically applied compressive forces and immobilization cause changes in the biomechanical behavior and biochemical composition of rat tail intervertebral discs. SUMMARY OF BACKGROUND DATA: Mechanical factors are associated with degenerative disc disease and low back pain, yet there have been few controlled studies in which the effects of compressive forces on the structure and function of the disc have been isolated. METHODS: The tails of 16 Sprague-Dawley rats were instrumented with an Ilizarov-type apparatus. Animals were separated into sham, immobilization, and compression groups based on the mechanical conditions imposed. In vivo biomechanical measurements of disc thickness, angular laxity, and axial and angular compliance were made at 14-day intervals during the course of the 56-day experiment, after which discs were harvested for measurement of water, proteoglycan, and collagen contents. RESULTS: Application of pins and rings alone (sham group) resulted in relatively small changes of in vivo biomechanical behavior. Immobilization resulted in decreased disc thickness, axial compliance, and angular laxity. Chronically applied compression had effects similar to those of immobilization alone but induced those changes earlier and in larger magnitudes. Application of external compressive forces also caused an increase in proteoglycan content of the intervertebral discs. CONCLUSIONS: The well-controlled loading environment applied to the discs in this model provides a means of isolating the influence of joint-loading conditions on the response of the intervertebral disc. Results indicate that chronically applied compressive forces, in the absence of any disease process, caused changes in mechanical properties and composition of tail discs. These changes have similarities and differences in comparison with human spinal disc degeneration.

Animals↗
PubMed1959

Laminectomy for herniated intervertebral disc.

In a study of 59 patients surgically treated by various surgeons for relief of herniated lumbar intervertebral disc accompanied by symptoms that persistently recurred or had become resistant to conservative therapy, it was noted from review of hospital and office records that laminectomy either greatly relieved or entirely abated symptoms in 83 per cent of the cases. Postoperative complications reported by the surgeons who did the operations consisted of one death and five wound infections. Contrast myelography and electromyography, used in almost all cases in the series, appeared to be valuable adjuncts in the diagnosis of herniated lumbar intervertebral discs. The most common site of the lesion in this series was between the fourth and fifth lumbar vertebrae. Strain upon lifting was the most commonly reported precipitating factor.

Humans↗
PubMed2006

Cervical intervertebral disc degeneration induced by unbalanced dynamic and static forces: a novel in vivo rat model.

STUDY DESIGN: Establishment of a novel in vivo animal model of cervical spondylosis. OBJECTIVE: To investigate apoptotic, degenerative, and inflammatory changes occurring in the cervical intervertebral discs of rats. SUMMARY OF BACKGROUND DATA: Cervical degeneration occurs as the result of imbalance of both static and dynamic spinal stabilizers. The disc degeneration that occurs is characterized by increased local inflammation and increased apoptosis of intervertebral disc cells. METHODS: By excising the paraspinal musculature and posterior cervical spinal ligaments of rats, both static and dynamic cervical stabilizers were disrupted. The resultant biomechanical imbalance resulted in biochemical and histologic changes, which were characterized by light microscopy, electron microscopy, immunostaining, enzyme-linked immunosorbent assay, polymerase chain reaction, and in situ hybridization. RESULTS: Histologic analysis showed characteristic degenerative changes of the intervertebral discs and vertebral endplates following surgery. Ultrastructural examination revealed apoptotic changes, which were verified by immunostaining. Instability also resulted in significant up-regulation of inflammatory factors, as shown by enzyme-linked immunosorbent assay, polymerase chain reaction, and in situ hybridization. CONCLUSIONS: By creating static and dynamic posterior instability of the cervical spine, this novel model of cervical spondylosis results in rapid intervertebral disc degeneration characterized by increased apoptosis and local inflammation, such as that seen clinically.

Animals↗
PubMed1987

Incidence and risk factors of herniated lumbar intervertebral disc or sciatica leading to hospitalization.

Hospital admissions for herniated lumbar intervertebral disc or sciatica were followed up over a period of 11 years in 57,000 men and women who had participated in medical check-ups in various parts of Finland. Information on their hospitalizations after the baseline examination was obtained by record linkage to the National Hospital Discharge Register. To identify factors predicting back diseases, four controls matched individually for sex, age and place of residence were chosen for each of the 592 incidence cases who were free from severe back trouble and aged 20-59 at entry. Low or intermediate social class and blue-collar occupations in services or industry in men and symptoms suggesting psychological distress in women proved significant predictors for hospitalization due to herniated lumbar disc or sciatica. An association with the risk was suggested for smoking or chronic cough in men and parity in women. Marital status or leisure time physical activity were not predictive of herniated lumbar intervertebral disc or sciatica.

Adolescent↗