Dominance of chemokine ligand 2 and matrix metalloproteinase-2 and -9 and suppression of pro-inflammatory cytokines in the epidural compartment after intervertebral disc extrusion in a canine model

BACKGROUND CONTEXT In canine intervertebral disc (IVD) disease, a useful animal model, only little is known about the inflammatory response in the epidural space. PURPOSE To determine messenger RNA (mRNA) expressions of selected cytokines, chemokines, and matrix metalloproteinases (MMPs) qualitatively and semiquantitatively over the course of the disease and to correlate results to neurologic status and outcome. STUDY DESIGN/SETTING Prospective study using extruded IVD material of dogs with thoracolumbar IVD extrusion. PATIENT SAMPLE Seventy affected and 13 control (24 samples) dogs. OUTCOME MEASURES Duration of neurologic signs, pretreatment, neurologic grade, severity of pain, and outcome were recorded. After diagnostic imaging, decompressive surgery was performed. METHODS Messenger RNA expressions of interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, tumor necrosis factor (TNF), interferon (IFN)γ, MMP-2, MMP-9, chemokine ligand (CCL)2, CCL3, and three housekeeping genes was determined in the collected epidural material by Panomics 2.0 QuantiGene Plex technology. Relative mRNA expression and fold changes were calculated. Relative mRNA expression was correlated statistically to clinical parameters. RESULTS Fold changes of TNF, IL-1β, IL-2, IL-4, IL-6, IL-10, IFNγ, and CCL3 were clearly downregulated in all stages of the disease. MMP-9 was downregulated in the acute stage and upregulated in the subacute and chronic phase. Interleukin-8 was upregulated in acute cases. MMP-2 showed mild and CCL2 strong upregulation over the whole course of the disease. In dogs with severe pain, CCL3 and IFNγ were significantly higher compared with dogs without pain (p=.017/.020). Dogs pretreated with nonsteroidal anti-inflammatory drugs revealed significantly lower mRNA expression of IL-8 (p=.017). CONCLUSIONS The high CCL2 levels and upregulated MMPs combined with downregulated T-cell cytokines and suppressed pro-inflammatory genes in extruded canine disc material indicate that the epidural reaction is dominated by infiltrating monocytes differentiating into macrophages with tissue remodeling functions. These results will help to understand the pathogenic processes representing the basis for novel therapeutic approaches. The canine IVD disease model will be rewarding in this process.

Sensory innervation of the dorsal longitudinal ligament and the meninges in the lumbar spine of the dog

Although intervertebral disc herniation is a well-known disease in dogs, pain management for this condition has remained a challenge. The goal of the present study is to address the lack of information regarding the innervation of anatomical structures within the canine vertebral canal. Immunolabeling was performed with antibodies against protein gene product 9.5, Tuj-1 (neuron-specific class III β-tubulin), calcitonin gene-related peptide, and neuropeptide Y in combination with the lectin from Lycopersicon esculentum as a marker for blood vessels. Staining was indicative of both sensory and sympathetic fibers. Innervation density was the highest in lateral areas, intermediate in dorsal areas, and the lowest in ventral areas. In the dorsal longitudinal ligament (DLL), the highest innervation density was observed in the lateral regions. Innervation was lower at mid-vertebral levels than at intervertebral levels. The presence of sensory and sympathetic fibers in the canine dura and DLL suggests that pain may originate from both these structures. Due to these regional differences in sensory innervation patterns, trauma to intervertebral DLL and lateral dura is expected to be particularly painful. The results ought to provide a better basis for the assessment of medicinal and surgical procedures.

Cultivation and expansion of canine Schwann cells using reexplantation

Despite the numerous available possibilities for the surgical treatment of peripheral nerve lesions found in the dog, the success of these treatments is often unsatisfactory. It has been proven that Schwann cells (SC) have a positive influence on the regeneration of nerve stumps. Implanting a guidance channel seeded with autologous SC at the lesion site could be a new therapeutic approach. The aim of this research was to investigate the in vitro cultivation and expansion of canine SC as the main requirement for the treatment referred to above. Biopsies were carried out on 17 nerve samples originating from dogs of different breed, age, gender and condition. The reexplantation method was employed, followed by dissociation using hyaluronidase, collagenase and trypsin and further expansion. The samples were divided into six groups which were treated with a varying combination of mitogens (forskolin, bovine PEX, choleratoxin, heregulin). To obtain the quantities of SC, the specimens were immunostained by a p75-antibody. By employing a growing number of agents it was possible to obtain an increase in both the quantity of cells and purity of cultures. A maximum of 16x10(5) cells per millilitre of suspension was achieved. The largest SC purity measured 27.1%. The maximum SC quantity achieved was 43.3x10(4) SC per millilitre.

Transvenous demand Pacemaker Treatment for intermittent complete Heart Block in a Cat

A 13-year-old male neutered domestic shorthaired cat had repeated syncopal episodes over a 6 month period, which had variable duration and continued to increase in frequency. Intermittent ventricular asystole, due to complete heart block, and hyperthyroidism were documented. As the syncopal episodes did not respond to a 4-week medical treatment and symptoms became severe, a transvenous ventricular demand pacemaker system (VVIM) was implanted via the external jugular vein. The unipolar lead was tunneled subcutaneously and connected with the generator in a preformed ventral abdominal muscle pocket. During follow up of 18-months there were no recurrences of the syncopal episodes.

CT myelography for diagnosis of brachial plexus avulsion in small animals

Avulsion of nerve roots of the brachial plexus can be diagnosed clinically, neurologically, radiographically and by electromyography. But like the myelography these techniques are inprecise for determination of the severity (partial or complete disruption) and the localization of the lesion. In human medicine the combination of computerized tomography with myelography shows high accuracy. Veterinary reports of experience in this field are not yet known. The aim of the present study was to demonstrate nerve root avulsions using myelography and computerized tomography. Three dogs and one cat with traumatic lesions of the brachial plexus were examined. The lesion could be seen in all patients. Thus CT-myelography results in an improved prognostic assessment of brachial plexus paralysis. Moreover, this technique could become one of the most important diagnostic methods for brachial plexus lesions involving nerve root reinsertion--neurotizations in veterinary medicine.