Enhanced type X collagen expression in the extruded nucleus pulposus of the chondrodystrophoid dog

The causes of early degeneration and calcification of the nucleus pulposus in the chondrodystrophoid dog are poorly understood, and the underlying molecular mechanism of this process has not yet been clearly defined. Type X collagen is one of the key molecules in endochondral bone growth and development, especially matrix calcification. The relationship between type X collagen and disc degeneration and calcification in chondrodystrophoid dogs has not yet been studied. We analyzed the expression of type X collagen in degeneration and calcification of the intervertebral disc in chondrodystrophoid dogs, using type X collagen immunohistochemistry. Control intervertebral discs were collected from five dogs (4 female, 1 male, average age 1.3 years, beagle breed). Degenerated intervertebral discs were surgically removed from 11 canine patients with intervertebral disc extrusion (1 female, 10 male, average age 5.1 years, dachshund breed) in Nippon Veterinary and Animal Science University. All extruded disc samples showed hypertrophic changes and clustering of cells, typical features observed in the degenerated nucleus pulposus. The relative expression of type X collagen in the degenerated nucleus pulposus (84.3 +/- 11.0%) was significantly increased compared to the control nucleus pulposus (5.4 +/- 5.4%). Our findings suggest that type X collagen might contribute to the development of degeneration or calcification in the nucleus pulposus of the chondrodystrophoid dog.     

Calcification of Intervertebral Discs in the Dachshund: A Radiographic Study of 21 Stud-Dogs

The vertebral columns of 21 clinically normal, 4.9 to 13.2 year old dachshunds were x-rayed. This sample represented 55.3% of all male dachshunds with 20 or more offspring registered with the Norwegian Kennel Club in the period 1985-1989.Calcified intervertebral discs were identified in 9 (42.9%) of the stud-dogs, and the number of calcified discs in each individual varied from 2 to 5 with a mean of 3.7. The frequency of stud-dogs with 1 or more calcified discs was compared with the corresponding frequency in a material of 327 one-year-old dachshunds. In this comparison, the relative risk was estimated with 95% confidence bounds. When the different composition of size and coat varieties in the 2 materials was not considered, the relative risk of calcified discs was found to be 1.77 (0.99-3.2) times higher in stud-dogs than in young dogs. When the different composition of varieties in the 2 materials was considered, the relative risk was found to be 1.9 (1.1-3.4) times higher in stud-dogs than in young dogs. The results of the present study strongly suggest that an increase in the frequency of dachshunds with 1 or more calcified intervertebral discs occurs after 1 year of age.     

Calcification of intervertebral discs in the dachshund. A radiographic study of 327 young dogs.

The vertebral columns of 327 clinically normal, 12 to 18 months old dachshunds, were x-rayed. This sample represented 16.1% of all dachshunds registered with the Norwegian Kennel Club in the period 1986-1988. Calcified intervertebral discs were identified in 79 (24.2%) of the dogs and the number of calcified discs in each individual varied from 1 to 11 with a mean of 2.3. Calcified discs were estimated to occur in 23.5% of Norwegian dachshunds. The occurrence of calcified discs in standard-sized dachshunds was higher in the wirehaired variety (27.1%) than in the smoothcoated (16.4%) or longhaired (9.1%) varieties. However, within the longhaired variety the occurrence was higher in dwarfs and kaninchens (36.0%) than in standard-sized dachshunds (9.1%). Calcification was identified in all cervical, thoracic and lumbar intervertebral discs other than T1-2, and was found to be most frequent in the caudal thoracic vertebral column.     

Osteochondrosis and arthrosis in pigs. II. Incidence in breeding animals

Joint and bone lesions in Norwegian breeding pigs are described on the background of an investigation involving 174 sows and 155 boars from 7 months to 4½ years old. Lesions, which consisted predominantly of arthrosis, degeneration of intervertebral discs, spondylosis and epiphyseal separations, were demonstrated frequently in both sexes. Osteochondrosis, a condition previously demonstrated frequently in slaughter pigs, had either completely healed, undergone repair or developed into an arthrosis by the time the animal reached an age of about 1½ years.Whereas a higher incidence of arthrosis of the intervertebral joints was found in boars than in sows, the reverse was true as regards degeneration of the intervertebral discs and anchylosing spondylosis. Possible reasons for this are discussed. Norwegian pigs show a higher incidence of lesions in the lumbar region of the vertebral column than has been described up to the present time in other countries.     

Equine cervical intervertebral disc degeneration is associated with location and MRI features

Morphology of the equine cervical intervertebral disc is different from that in humans and small companion animals and published imaging data are scarcely available. The objectives of this exploratory, methods comparison study were (a) to describe MRI features of macroscopically nondegenerated and degenerated intervertebral discs (b) to test associations between spinal location and macroscopic degeneration or MRI‐detected annular protrusion and between MRI‐detected annular protrusion and macroscopic degeneration, and (c) to define MRI sequences for characterizing equine cervical intervertebral disc degeneration. Ex vivo MRI of intervertebral discs was performed in 11 horses with clinical signs related to the cervical region prior to macroscopic assessment. Mixed‐effect logistic regression modeling included spinal location, MRI‐detected annular protrusion, and presence of macroscopic degeneration with “horse” as random effect. Odds ratio and 95% confidence interval were determined. Reduced signal intensity in proton density turbo SE represented intervertebral disc degeneration. Signal voids due to presence of gas and/or hemorrhage were seen in gradient echo sequences. Presence of macroscopic intervertebral disc degeneration was significantly associated with spinal location with odds being higher in the caudal (C5 to T1) versus cranial (C2 to C5) part of the cervical vertebral column. Intervertebral discs with MRI‐detected annular protrusion grades 2‐4 did have higher odds than with grade 1 to have macroscopic degeneration. It was concluded that MRI findings corresponded well with gross macroscopic data. Magnetic resonance imaging of the equine cervical intervertebral disc seems to be a promising technique, but its potential clinical value for live horses needs to be explored further in a larger and more diverse population of horses.     

Expression of ADAMTS-7 and ADAMTS-12 in the nucleus pulposus during degeneration of rat caudal intervetebral disc

Earlier reports have shown that ADAMTS-7 and ADAMTS-12 (a disintegrin and metalloproteinase with thrombospondin motifs) can bind to and degrade COMP (cartilage oligomeric matrix protein) in cartilage. However, the expression of ADAMTS-7 AND ADAMSTS-12 in both normal intervertebral discs and degenerative intervertebral discs (IVDs) is still unknown and the changes that occur in the degenerating intervertebral disc remain to be determined. The aim of this study was to explore the expression and role of the ADAMTS in the degenerative process of the intervertebral disc. Rat caudal discs were loaded at 1.3 MPa in vivo with an external compression device. The discs were loaded for one week, and and the nuclei pulposi (NPs) were harvested to investigate cell apoptosis and expression of collagen II and aggrecan for confirmation of disc degeneration. The changes of ADAMTS-7 and ADAMTS-12 and COMP were recorded during one week of loading. A second group of rats receiving no load were used as controls. After one week of loading, the NPs suffered degenerative changes as reflected by decreases in cell viability, collagen II, and aggrecan. Dramatic increases in expression of ADAMTS-7 and ADAMTS-12 and COMP fragment were detected after 18 hr of loading; however, this was accompanied by a sharp decrease of COMP expression. These changes were not observed in the control group. The significant increase in COMP possibly suggests a favorable role of COMP in preventing loading and degeneration of matrix; however, this positive effect might be diminished by ADAMTS-7 and ADAMTS-12, whose augmentation were dramatic during disc degeneration.     

Calcification of Intervertebral Discs in the Dachshund: An Estimation of Heritability

The heritability of calcified intervertebral discs in the dachshund was estimated using data gathered from a radiographic study. Radiographs of the vertebral columns of 274 clinically normal, 12 to 18 months old dachshunds, were examined. The dogs were offspring from 75 different sires, representing the same number of half sib groups. There were 2 to 14 offspring in each half-sib group. The number of full sib groups was 81.Calcified intervertebral discs were identified in 20.4 % of the dogs. An analysis of variance that used the data as a continuous and as an either/or-variable estimated the heritability of calcified discs to be 0.22 and 0.15 respectively.A genetic factor was found to be essential for the occurrence of calcified discs in a dog while a common environmental factor presumably resulting from non-genetic causes was significant in determining the number of discs to undergo calcification in affected dogs.     

Review of the use of transrectal ultrasonography for evaluation of the caudal lumbar – including lumbosacral – intervertebral discs and symphyses: Normal and abnormal ultrasonographic appearance

Transrectal ultrasonography of the lumbosacroiliac area is routinely performed for the diagnosis of the cause of low back pain and poor hindlimb impulsion and engagement. The ventral aspect of the caudal lumbar intervertebral discs and vertebrae can be easily assessed transrectally with ultrasound while other imaging modalities have limitations for diagnosis of intervertebral disc injuries. This paper is a review of the ultrasonographic procedure for imaging the ventral aspect of the caudal lumbar and lumbosacral symphyses, especially the intervertebral discs. Normal images, findings and lesions of the three caudalmost lumbar intervertebral discs are described (between the 4th lumbar and the 1st sacral vertebrae).     

Immunhistochemical Demonstration of Lumbar Intervertebral Disc Innervation in the Dog

Low back pain is a common ailment in dogs, particularly in specific breeds as for instance the German shepherd dog. A number of structures such as facet joint capsules, ligaments, dorsal root ganglia, periosteum, vertebral endplate, and meninges have been associated with this condition. However, in a substantial proportion of all cases, the origin of pain remains obscure. A further structure often being involved in vertebral column disorders is the intervertebral disc. However, the presence of nerves is a precondition for pain sensation and, consequently, structures lacking sensory innervation can be left out of consideration as a cause for low back pain. Nerve fibres have been demonstrated at the periphery of intervertebral discs in man, rabbit and rat. With regard to the dog, however, extent of intervertebral disc innervation still is disputed. The goal of the present study, therefore, was to assess previous findings based on silver impregnation. Protein gene product (PGP) 9.5 was used as a marker for immunohistochemical examination of serial transversal and sagittal paraffin sections of lumbar discs from adult dogs. This technique revealed nerve fibres to be confined to the periphery of the intervertebral discs. Thus, even limited pathological processes affecting the outer layers of the intervertebral disc are prone to cause low back pain.     

Severity and distribution of ventral thoracolumbar spondylosis and histological assessment of associated intervertebral disc degeneration in cull rams

AIM: To conduct a pilot study investigating the incidence and pathology of spondylosis in a sample of cull rams in New Zealand. METHODS: Vertebral columns from 51 cull rams from different properties were assessed radiographically for evidence of spondylosis. They were graded according to severity, using a four-point grading system. Samples of intervertebral discs representing different grades of spondylosis were examined histopathologically. RESULTS: Forty (78%) rams had spondylosis in at least one intervertebral space. Of these, 11 had ankylosis involving one or more intervertebral spaces. The frequency of spondylosis was greater in the thoracic than lumbar region (p<0.001), and was most frequent between T10-T11. Histopathological examination of intervertebral discs associated with all grades of spondylosis revealed degenerative changes in the annulus fibrosis. CONCLUSIONS: Spondylosis appeared to be common in cull rams and affected thoracic and lumbar vertebrae. It often involved ankylosis of adjacent vertebrae, and was associated with degeneration of the intervertebral disc. CLINICAL RELEVANCE: Spondylosis may reduce the serving ability of rams and be an important underlying reason for culling. The pathogenesis of spondylosis is unknown but may involve high mating frequencies during the breeding season.     

Scanning electron microscopy of vascular architecture in the mucosa of sheep omasal laminae

Three dimensional vascular architecture in the omasal laminae of sheep was studied by scanning electron microscopy of corrosion casts. The omasal laminae were equipped with well-developed subepithelial capillary network with various capillary loops and inter-papillar undulations. The capillary loops were more highly developed in the omasal papillae than in the inter-papillar space and more in the oral region than in the aboral. The capillary loops were inconspicuous in the inter-papillar space of the middle and aboral regions and in the omasal papillae of the aboral region. On the other hand, the inter-papillar undulation of the capillary network was more conspicuous in the aboral region than in the other regions of the omasal mucosa. These findings may indicate a regional diversity in the function of the omasal laminae.     

COMPARISON BETWEEN COMPUTED TOMOGRAPHY,FLUOROSCOPY, AND ULTRASONOGRAPHY FOR GUIDING PERCUTANEOUS INJECTION OF THE CANINE INTERVERTEBRAL DISC

A minimally invasive method for delivering injectable therapeutic agents would be desirable for the treatment of intervertebral disc disease in dogs. The purpose of this study was to compare computed tomography (CT), ultrasonography (US), and fluoroscopy modalities for guiding percutaneous injection into canine intervertebral discs. Intervertebral discs of 14 dog cadavers were injected with a gelified ethanol therapeutic agent. Successful injectate placement and injectate leakage were determined based on necropsy inspection of discs. Injection into the nucleus pulposus was successful in 55 of 78 (71%) of all injected discs. Injections guided using CT and fluoroscopy were significantly more successful than US‐guided injections. Odds of successful injection without leakage were greater for CT vs. US (P = 0.0026) but there was no significant difference between CT and fluoroscopy (P = 0.0620). Injection success rates did not differ among vertebral sites or dog cadavers of varying weights. Forty‐nine (63%) of injection sites had injectate leakage outside the disc and 10 of these involved structures within the vertebral canal. The highest rate of injection success with the least amount of leakage was achieved with CT guidance. Findings indicated that CT, fluoroscopy, and US are feasible modalities for guiding percutaneous injection of a gelified ethanol therapeutic agent into the canine intervertebral disc, with moderate to high success rates for different regions of the spine. However, a moderately high rate of injectate leakage occurred outside of the disc and this should be taken into consideration for future safety and efficacy studies.     

Genetic factors in the maturation of the canine intervertebral disc.

The composition and structure of the intervertebral discs have been studied in a group of six four-month-old beagles which were full or half-siblings. The animals were raised in identical environment and were comparable weight and size at sacrifice. Collagen, hexosamine, uronic acid, sialic acid and non-collagenous protein analysis (via indirect method) were performed on the nucleus pulposus (NP), transitional zone (TZ) and a annulus fibrosus (AF) of the discs for the lumbo-sacral, lumbar and thoracic spinal levels. Parallel histochemical and morphological examinations of the discs were also performed. The knee joint meniscus, and articular cartilage was also examined for the components described. The results of the analysis for the discs revealed that within this single age group there co-exist two statistically different compositional states. These differences reside largely in the NP and TZ regions and from the analytical values are interpreted as indicating the chondroid and non-chondroid conditions. No such compositional variation was observed for articular cartilage and fibrocartilage (knee joint menisci).     

Relationship between intervertebral joint morphology and mobility in the equine thoracolumbar spine

The anatomical features of 21 equine thoracolumbar spines, obtained from horses with clinically normal backs, were examined and the results compared with recent data on the mobility of the joint complexes of the horse's spine. The thoracolumbar spine can be divided into four regions based upon the morphology of the joint complexes: the first thoracic intervertebral joint (T1-2), the cranial and mid thoracic region (T2-T16), the caudal thoracic and lumbar region (T16-L6) and the lumbosacral joint. The mobility of the intervertebral joints in each of these regions can be related to their morphology, particularly the shape, size and orientation of the articular facets and the presence and frequent fusion of the lateral joints of the lumbar spine. The shape and thickness of the intervertebral discs also appear to be of importance.     

Immunohistochemical demonstration of lumbar intervertebral disc innervation in the dog

Low back pain is a common ailment in dogs, particularly in specific breeds such as the German shepherd dog. A number of structures such as facet joint capsules, ligaments, dorsal root ganglia, periosteum, vertebral endplates and meninges have been associated with this condition. Yet, in spite of all diagnostic efforts, the origin of pain remains obscure in a substantial proportion of all cases. A further structure often being involved in vertebral column disorders is the intervertebral disc. The presence of nerves, however, is a precondition for pain sensation and, consequently, structures lacking innervation can be left out of consideration as a cause for low back pain. Nerve fibres have been demonstrated at the periphery of the intervertebral disc in man, rabbit and rat. With regard to the dog, however, the extent of intervertebral disc innervation is still being disputed. The goal of the present study, therefore, was to substantiate and expand current knowledge of intervertebral disc innervation. Protein gene product (PGP) 9.5 was used for immunohistochemical examination of serial transversal and sagittal paraffin sections of lumbar discs from adult dogs. This general marker revealed nerve fibres to be confined to the periphery of the intervertebral discs. These results indicate that even limited pathological processes affecting the outer layers of the intervertebral disc are prone to cause low back pain.     

Chemonucleolysis with Collagenase A Radiographic and Pathologic Study in Dogs

Collagenase, a proteolytic enzyme, was injected intradiscally in nine clinically normal, middle-aged beagles. Calcium chloride diluent solution (control), 100 ABC units of collagenase, and 250 ABC units of collagenase, were injected in randomly selected intervertebral discs (T13-L1 to L5-L6). On day 11, the discs injected with collagenase were narrowed radiographically, but there was no significant change in myelograms. Grossly and histologically, there was dissolution of the intervertebral discs, mainly nucleus pulposus, and protrusion of nucleus material in the vertebral body through bony end-plates in discs injected with collagenase. Collagenase chemonucleolysis may be an alternative to spinal surgery for intervertebral disc protrusion in dogs.     

Intervertebral disc extrusion in six cats

Existing reports concerning intervertebral disc disease (IVDD) have focused almost exclusively on dogs, although a small number of individual case reports of IVDD of cats has been published. The medical records of six cats with IVDD were reviewed. Radiographic studies confirmed narrowed intervertebral disc spaces, mineralised intervertebral discs, and one or more extradural compressive lesions of the spinal cord in each cat. All disc extrusions were located in the thoracolumbar region. Surgical decompression of the spinal cord was achieved in all cats by means of hemilaminectomy and removal of compressive extradural material confirmed to be degenerative disc material. Good to excellent neurological recovery was noted in five of the six cats included in this report. Based on this review, it appears that IVDD of cats has many similarities to IVDD of dogs, and that healthy cats with acute intervertebral disc extrusion(s) respond favourably to surgical decompression of the spinal cord.     

Discal cysts of the cervical spine in two dogs

Discal cysts, which lie directly over intervertebral discs, are rare. Two old dogs with tetraparesis were referred to our facility. In both animals, magnetic resonance imaging revealed intraspinal extradural cystic mass lesions that were dorsal to degenerative intervertebral discs at the C3-C4 level. These lesions had low signal intensity on T1-weighted images, and high signal intensity on T2-weighted images. A ventral slot approach was used to perform surgical decompression, after which the symptoms improved remarkably. Discal cysts should be included in the differential diagnosis of dogs with cervical pain and tetraparesis. One effective treatment for discal cysts is surgical intervention.