Sodium iodoacetate induced osteoarthrosis model in rabbit temporomandibular joint: CT and histological study (part I)

Studies to elucidate the pathophysiology of osteoarthrosis have been hampered by the lack of a rapid, reproducible animal model that mimics the histopathology and symptoms associated with the disease. The aim of this study is to evaluate the radiological, histological and histomorphometrical findings of four different concentrations of sodium iodoacetate (MIA) to create osteoarthrosis by using an arthrocentesis technique on rabbit temporomandibular joint (TMJ). 12 New Zealand white male rabbits received an injection of MIA (50 μl dose of 1.5, 2, 2.5, 3mg/ml concentrations) to a single joint of each group by arthrocentesis. Computed tomography (CT) images were obtained pre- and post-injections at 2, 4 and 6 weeks. Early osteoarthritic changes in the rabbit TMJ were found histologically at 4 weeks and with a 3mg/ml concentration of MIA. The mean subchondral bone volume depended on the concentration of MIA and was 62±2.6%, 63±4.1%, 42±3.6% and 38±3.8%, respectively. A minor abnormality was found on CT in six joints at the 4-week follow up. MIA injection and arthrocentesis offer a rapid and minimally invasive method of reproducing histologically osteoarthrotic lesions in the rabbit TMJ.

Transcriptional profiling and pathway analysis of monosodium iodoacetate-induced experimental osteoarthritis in rats: relevance to human disease

OBJECTIVE

The objective of this study was to characterize the rat monosodium iodoacetate (MIA)-induced model for osteoarthritis (OA) and determine the translatability of this model to human disease. This was accomplished through pathway, network and system level comparisons of transcriptional profiles generated from animal and human disease cartilage.

METHODS

An OA phenotype was induced in rat femorotibial joints following a single injection of 200mug MIA per knee joint for a period of 2 or 4 weeks. Lesion formation in the rat joints was confirmed by histology. Gene expression changes were measured using the Agilent rat whole genome microarrays. Cartilage was harvested from human knees and gene expression changes were measured using the Agilent human arrays.

RESULTS

One thousand nine hundred and forty-three oligos were differentially expressed in the MIA model, of these, approximately two-thirds were up-regulated. In contrast, of the 2130 differentially expressed oligos in human disease tissue, approximately two-thirds were down-regulated. This dramatic difference was observed throughout each level of the comparison. The total overlap of genes modulated in the same direction between rat and human was less than 4%. Matrix degradation and inflammatory genes were differentially regulated to a much greater extent in MIA than human disease tissue.

CONCLUSION

This study demonstrated, through multiple levels of analysis, that little transcriptional similarity exists between rat MIA and human OA derived cartilage. As disease modulatory activities for potential therapeutic agents often do not translate from animal models to human disease, this and like studies may provide a basis for understanding the discrepancies.

Vasoactive intestinal peptide (VIP) is a modulator of joint pain in a rat model of osteoarthritis

Osteoarthritis (OA) is a debilitating disease in which primarily weight-bearing joints undergo progressive degeneration. Despite the widespread prevalence of OA in the adult population, very little is known about the factors responsible for the generation and maintenance of OA pain. Vasoactive intestinal peptide (VIP) was identified in the synovial fluid of arthritis patients nearly 20 years ago and the aim of this study was to examine whether VIP could be involved in the generation of OA pain. Hindlimb weight bearing was used as a measure of joint pain, while von Frey hair algesiometry applied to the plantar surface of the ipsilateral hindpaw tested for secondary mechanical hyperalgesia. Intra-articular injection of VIP into normal rat knee joints caused a significant shift in weight bearing in favour of the contralateral non-injected hindlimb as well as causing a reduction in ipsilateral paw withdrawal threshold. These pain responses were blocked by co-administration of the VPAC receptor antagonist VIP6-28. Induction of OA by intra-articular sodium monoiodoacetate injection resulted in a reduction in weight bearing on the affected leg, but no evidence of secondary hyperalgesia in the paw. Treatment of OA knees with a single injection of VIP6-28 diminished hindlimb incapacitance while increasing paw withdrawal threshold. This study showed for the first time that peripheral application of VIP causes increased knee joint allodynia and secondary hyperalgesia. Furthermore, antagonists that inhibit VIP activity may prove beneficial in the alleviation of OA pain.

Mono-iodoacetate-induced histologic changes in subchondral bone and articular cartilage of rat femorotibial joints: an animal model of osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease characterized by joint pain and a progressive loss of articular cartilage. Studies to elucidate the pathophysiology of OA have been hampered by the lack of a rapid, reproducible animal model that mimics both the histopathology and symptoms associated with the disease. Injection of mono-iodoacetate (MIA), an inhibitor of glycolysis, into the femorotibial joint of rodents promotes loss of articular cartilage similar to that noted in human OA. Here, we describe the histopathology in the subchondral bone and cartilage of rat (Wistar) knee joints treated with a single intra articular injection of MIA (1 mg) and sacrificed at 1, 3, 5, 7, 14, 28, and 56 days postinjection. Histologically, the early time points (days 1-7) were characterized by areas of chondrocyte degeneration/necrosis sometimes involving the entire thickness of the articular cartilage in the tibial plateaus and femoral condyles. Changes to the subchondral bone, as evidenced by increased numbers of osteoclasts and osteoblasts, were noted at by day 7. By 28 days, there was focal fragmentation and collapse of bony trabeculae with fibrosis and increased osteoclastic activity. By 56 days there were large areas of bone remodeling evidenced by osteoclastic bone resorption and newly formed trabeculae with loss of marrow hematopoietic cells. Subchondral cysts and subchondral sclerosis were present in some rats. In conclusion, intra-articular injection of MIA induces loss of articular cartilage with progression of subchondral bone lesions that mimic those of OA. This model offers a rapid and minimally invasive method to reproduce OA-like lesions in a rodent species.

In vivo micro computed tomography of subchondral bone in the rat after intra-articular administration of monosodium iodoacetate

Osteoarthritis (OA) is a degenerative disease that is characterized by joint discomfort, loss of articular cartilage, and changes to the subchondral bone. Studies to elucidate the pathophysiology of OA have been hampered by the lack of a rapid, reproducible animal model that mimics the structural changes associated with the disease. A single intra-articular injection of mono-iodoacetate (MIA), an inhibitor of glycolysis, into the femorotibial joint of rodents promotes loss of articular cartilage similar to that noted in human OA. The purpose of the present study was to determine whether in vivo three-dimensional micro computed tomography (microCT) was of use for detecting progressive changes over time to the subchondral bone (femorotibial joint) of Wistar rats treated with a single intra-articular injection of MIA. MIA-treated right knee joints and left contralateral control knee joints were imaged in vivo at 0, 1, 7, 14, 28, and 56 days postinjection by using microCT. Analysis of 50- and 100- micro m resolution images demonstrated that changes to the subchondral bone, as determined by visual and bone mineral density analysis, are apparent by day 14 post-MIA. By day 28, there were marked changes to lateral aspect of the medial tibial plateaus of the subchondral bone in MIA-treated joints. These changes were progressive through day 56. It was concluded that intra-articular injection of MIA induces progressive changes to subchondral bone that can be assessed using in vivo microCT imaging. In light of these data, in vivo microCT imaging represents a valuable tool for investigating bone remolding and has the potential to be used for routine, high-throughput analysis and screening of investigation therapeutics.

Chemical arthrodesis of the distal tarsal joints using sodium monoiodoacetate in 104 horses

OBJECTIVE

To evaluate chemical arthrodesis using sodium monoiodoacetate for treatment of degenerative joint disease of the tarsometatarsal and distal intertarsal joints.

DESIGN

Retrospective clinical study.

METHOD

Horses were diagnosed with degenerative joint disease of one or more of the tarsometatarsal or distal intertarsal joints based on history, lameness examination, radiographic findings and, in some cases, response to intra-articular anaesthesia or medication. Intra-articular injections of sodium monoiodoacetate were performed using 23 gauge needles in the sedated, standing horse. Positive contrast arthrography of the distal intertarsal joint was performed in all horses to evaluate needle placement and the presence or absence of communication with other synovial structures. The mean intra-articular dose of sodium monoiodoacetate was 192 mg. Horses were subject to a graded exercise program commencing 7 to 10 days after treatment. Where possible, follow up lameness examination and radiography was performed at 3, 6, 12 and 24 months after treatment.

RESULTS

At 3, 6, 12 and 24 months after treatment, respectively, 0/57, 14/55, 41/50, and 29/34 of horses were sound. At 3, 6, 12 and 24 months after treatment, respectively, 5/55, 24/38, 26/30 and 18/18 of horses had radiographic evidence of ankylosis of treated joints. Post injection pain was marked in 6.7% of horses and significant complications requiring further treatment occurred in 3.8% of horses.

CONCLUSIONS

Chemical arthrodesis using sodium monoiodoacetate was an effective treatment method for degenerative joint disease of the distal tarsal joints. The technique was performed in the sedated standing horse and required minimal equipment. Results were comparable to those achieved following surgical arthrodesis. The risk of significant complications was minimised through good technique using an appropriate injection volume and concentration.

Morphological analysis of iodoacetic acid-induced cataract in the rat

PURPOSE

To clarify the mechanism underlying the development of cataract in the rat lens after intraperitoneal administration of iodoacetic acid (IAA).

METHODS

(1) The 2% IAA dissolved in saline solution was injected at a dose of 40 mg/kg body weight into the rat peritoneal cavity. The retina and lens were intermittently extirpated and were examined by light and electron microscopy. (2) Two kinds of tracer, Evans blue (EB) and horseradish peroxidase (HRP), were injected into the tail veins and anterior chamber, and were observed with dissecting and electron microscopes.

RESULTS

(1) Four weeks after administration, a part of the lens epithelium at the lateral side of the lens was degenerated, and the lens nucleus developed faint turbidity after 8 weeks. After 16 weeks, the nuclear turbidity could not be observed because mild cortical opacity was developing. The epithelial degeneration recovered from around 12 weeks, and instead of spherical nuclei, elliptical nuclei appeared. (2) The EB dye injected into the tail vein significantly stained the ciliary body, where the anterior and posterior ciliary arteries anastomosed. EB injected from the lateral side of the lens was seen to move towards the lens nucleus. Electron microscopically, the epithelial degeneration of the ciliary body was observed. The incorporated HRP substance was found in the cytoplasm of the nonpigmented cells of the ciliary epithelium at an early stage after IAA administration.

CONCLUSION

IAA injected intravenously first developed epithelial degeneration at the lateral side of the lens. This change induced swelling of the lens fibers in the lens nucleus. Recovered epithelial cells had a transformed nucleus, and in turn the cortical cataract was induced by a differentiation disorder of the lens fibers. These results indicate that the breakdown of the blood-aqueous barrier in the nonpigmented epithelium of the ciliary body is a trigger to cause the cataract. The IAA-induced cataract may be useful as an animal model of human age-related cataract.

Moderation of iodoacetate-induced experimental osteoarthritis in rats by matrix metalloproteinase inhibitors

OBJECTIVE

To determine the effect of matrix metalloproteinase (MMP) inhibitors in mono-iodoacetate-induced arthritis in rats.

DESIGN

The ability of compounds to inhibit MMPs in vitro was assessed kinetically using a quenched fluorescent substrate. Rats were injected with iodoacetate intraarticularly in one knee joint and damage to the tibial plateau was evaluated from digitized images captured using an image analyser and by histology. Collagenase and gelatinase activity in cartilage from iodoacetate injected knees were evaluated using(3)H-rat type I collagen and gelatin zymography, respectively.

RESULTS

Collagenase and gelatinase activity significantly increased in the knee cartilage of rats injected with iodoacetate with peak activity by day 7. Three MMP inhibitors were examined for their efficacy in the rat iodoacetate-induced arthritis model. Significant (P< 0.05) inhibition of cartilage damage was observed in animals treated orally with 35 mg/kg b.i.d. of the three different MMP inhibitors. Inhibition of cartilage damage by the MMP inhibitors ranged from 36-42%.

CONCLUSION

MMP inhibitors are partially protective against cartilage and subchondral bone damage induced by iodoacetate. These results support an important role for MMPs in mediating the joint damage in this model of arthritis.

In vitro magnetic resonance microimaging of experimental osteoarthritis in the rat knee joint

OBJECTIVE

To visualize articular changes during iodoacetate induced osteoarthritis (OA) of the rat knee using high resolution magnetic resonance imaging (MRI).

METHODS

All images were acquired on a 8.5T microimager on ex vivo rat knees. After optimization studies, 3D spin echo sequences were used with TR 1200 ms and TE 15 ms; 40 sagittal images were obtained with a resolution of 400 x 60 x 60 microns. OA lesions were achieved by injecting 3 mg iodoacetate in the right knee joint (Day 0). Progression of OA changes was studied at Days 5, 10, 15, 20, 30, 90 and corresponding radiographs and histological sections were obtained.

RESULTS

Spin echo images of the normal rat knee clearly visualized cortical bone, calcified menisci, patella, and cruciate ligaments as dark regions. Cartilage and muscles appeared as intermediate signal. In some cases a trilaminar appearance of cartilage and growth plate was depicted. This appearance persisted at Day 5, although cartilage presented a marked loss of proteoglycans. After Day 10 the menisci appeared irregular and inhomogeneous. After Day 15, MRI showed important alterations of articular cartilage, predominant on weight bearing areas of femoral condyles. Osteophytic remodeling was also seen around the patella. From Day 20 to Day 90 anatomical changes progressively affected epiphyseal bone, leading to subchondral cysts and loss of its regular trabecular structure.

CONCLUSION

High field MRI provides a sensitive method for investigating ex vivo focal erosions of cartilage and established osteochondral remodeling in experimental OA in the rat. In this model, microimaging provides more information about early modifications of cartilage and soft tissue than radiographic exploration, in good correlation with histological data.

Use of sodium monoiodoacetate to fuse the distal hock joints in horses

Intra-articular injection of sodium monoiodoacetate (MIA) was investigated as an agent for chemical arthrodesis of the distal hock joints in the horse. Five horses diagnosed with either spavin (three horses), a small tarsal bone fracture or a failed surgical arthrodesis, had 150 mg of MIA injected into the tarsometatarsal (TMT) joint of the affected hock(s). Eight joints were treated in the five horses. Follow-up evaluation by clinical and radiological examination took place over 9 to 14 months. Two of the five horses were sound at the conclusion of the study and one horse, although lame after flexion, was considered by the owner to have been treated successfully. One of eight TMT joints showed complete radiographic fusion. Complications after treatment included pain, chronic lameness and swelling. It was concluded that chemical arthrodesis using this technique can not be recommended as being a superior treatment as compared with surgical arthrodesis at this time but is deserving of further clinical evaluation.

Comparison of lesions induced by intra-articular injections of quinolones and compounds damaging cartilage components in rat femoral condyles

Twenty-five microliters of a 2% saline solution of levofloxacin (LVFX) or ciprofloxacin (CPFX) was injected every other day for 2 wk into the knee joint space of CD rats (weighing 62.7-86.7 g) from the age of 3 wk. Early in the course of injection, histologic examination revealed chondrocyte necrosis without marked matrix change in the articular cartilage of the femoral condyles adjacent to the intercondylar groove. After 7 injections, the surface and intermediate zones of the articular cartilage showed extensive necrosis, sometimes with cavity formation in the center of the same portion. Papain completely depleted matrix basophilia in all zones throughout the condyle and caused cartilage necrosis with cavity formation. One injection of iodoacetic acid caused necrosis of almost all chondrocytes over the entire condyle, but chondrocytes sometimes remained alive in the portion where cavity formation was induced by quinolones. Chondroitinase depleted the matrix basophilia, and sometimes produced necrotic areas. DNA synthesis inhibitors n-ethylmaleimide, CPT-11, and etoposide (VP-16) caused chondrocyte necrosis, but never caused cavities in the articular cartilage. The DNA synthesis inhibitors n-ethylmaleimide, CPT-11, and hydroxyurea were administered concurrently with po LVFX administration and significantly increased the incidence of LVFX-induced cavity formation. n-Ethylmaleimide was the most effective of all the inhibitors. The quinolone-induced cavity formation is suggested to be site specific in the articular cartilage of rat femoral condyles. The depletion of matrix proteoglycans and chondrocyte necrosis may be necessary, although insufficient, to produce such lesions. Disruption of the collagen framework is suspected to contribute to their development. Involvement of altered DNA metabolism may play a role in the chondrocyte necrosis that occurs early in the specific sites.

Effects of intravenous iodoacetate and iodate on pH outside rod photoreceptors in the cat retina

PURPOSE

Effects of intravenous iodoacetate (a glycolysis inhibitor) and iodate (a metabolism inhibitor selective to retinal pigment epithelium) on light-evoked alkalinizations and hypoxia-induced acidifications were studied in the dark-adapted cat retina, in vivo, to learn about pH regulation.

METHODS

pH was recorded in the extracellular space surrounding rod photoreceptors with double-barrelled H(+)-selective microelectrodes.

RESULTS

Intravenous infusion of 5 mg/kg iodoacetate-induced alkalinizations in the outer nuclear layer and suppressed both light-evoked and hypoxia-induced pH responses immediately. Iodate injection (30 mg/kg) produced acidifications in the subretinal space and affected light-evoked alkalinizations gradually but not hypoxia-induced acidifications.

CONCLUSIONS

These results suggest that rods glycolysis plays an important role in both light-evoked and hypoxia-induced pH responses. And the retinal pigment epithelium may have little concern with light-evoked alkalinizations except that it plays an important role in regenerating the rhodopsin to be needed for the light responses of photoreceptors. Furthermore, the finding of the intravenous-iodoacetate-induced alkalinization in the outer nuclear layer supports that acid production by rods in the dark is originated from glycolysis to support the dark current. The iodate-induced acidification in the subretinal space indicators that the retinal pigment epithelium might actively transport acids from the subretinal space to the choroid.

Fusion of the distal intertarsal and tarsometatarsal joints in the horse using intraarticular sodium monoiodoacetate

Six normal horses received 3 intra-articular injections of sodium monoiodoacetate (MIA) in the distal intertarsal (DIT) and tarsometatarsal (TMT) joints of one hindlimb. Injections were at three week intervals, and post injection pain was controlled with routine administration of phenylbutazone for five days following each injection. All horses underwent a gradually increasing exercise programme consisting of walking and trotting beginning one week after the first injection and continuing for 24 weeks. All treated joints showed increasingly severe radiographic evidence of degenerative joint disease with time. Clinical signs were mild or absent during exercise. All treated joints showed radiographic and histological evidence of fusion 24 weeks after the first injection. Amount of radiographic fusion ranged from 54.49 per cent to 88.64 per cent of the joint space. Histologically, the joint space that appeared radiographically fused was filled mainly with woven and lamellar bone. Fibrocartilage and fibrous tissue was seen frequently in the transition between fused and unfused areas. Articular cartilage in unfused areas was thin, fibrillated, hypocellular and histochemically showed diminished proteoglycan content. Existing joint space was filled with fibrin and necrotic, acellular chondroid matrix. We conclude that MIA will produce fusion of the DIT and TMT joints of normal horses in 24 weeks, and may offer a relatively easy, inexpensive and non-invasive treatment for distal tarsal osteoarthritis in the horse.

Neurological protection by dichloroacetate depending on the severity of injury in the paraplegic rat

Hyperglycemia has been shown to exacerbate neurological deficit associated with central nervous system ischemia. Iodoacetate or dichloroacetate was administered intraperitoneally to rats in a study to examine the role of glycolysis in hyperglycemic exacerbation of neurological deficit. Sprague-Dawley rats were injected with saline, iodoacetate, or dichloroacetate and then made paraplegic by temporary occlusion for 10, 12, 13, or 15 minutes of the right and left subclavian arteries and the aorta distal to the left subclavian artery. Glycolytic blockage by iodoacetate was lethal in doses of 15 mg/kg or more, whereas rats receiving 10 mg/kg survived but showed no significant neurological improvement compared to the saline-treated control group. Dichloroacetate, 500 mg/kg, protected neurological function, which suggests a possible detrimental role for lactate accumulation and the benefit of maintaining tricarboxylic acid cycle activity by stimulating pyruvate dehydrogenase. The protection seen with dichloroacetate depended on the severity of ischemic injury. Dichloroacetate administration had a minimal effect on neurological outcome with occlusion periods of 13 and 15 minutes, mild improvement with 12 minutes of occlusion, and a significant protective effect with a 10-minute occlusion period. The dose-response nature of ischemic injury and neurological outcome in this rat model of paraplegia therefore appears to play an important role in determining the effect observed with a specific intervention.

Animal model of human disease: defective skeletal muscle glucose and/or glycogen metabolism

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In vitro effects of antiprotozoan drugs and immune serum on Pneumocystis carinii

The in vitro survival of Pneumocystis carinii isolated from the lungs of rats with glucocorticoid-induced pneumocystosis has been evaluated by quantitation of uptake of vital dyes by the organisms after exposure to a variety of drugs, immune serum, and medium enriched with macrophage lysosomal enzyme. On the basis of these tests, it appears that pentamidine and chloroquine are directly lethal to the organisms, but that suramin, trimethoprim, and sulfamethoxazole are not. Neither immune serum supplemented with complement and lysozyme nor the supernatant of phagocytosing macrophages appeared to affect the viability of the organisms. Inhibitors of glucose uptake and metabolism appeared to kill Pneumocystis, but neither cycloheximide nor iododeoxyuridine was effective.

Iodoacetate-induced inhibition and enhancement of spontaneous leukemia in AKR mice

Either inhibition or enhancement of the spontaneous lymphoma exhibited by AKR mice was observed after treatment with different dosages of the sulfhydryl inhibitor, sodium iodoacetate. Treatment of the mice at 3 or 6 months of age with five ip injections of 0.10 mg of iodoacetate at 5-day intervals significnatly extended the survival of the animals. A single administration of this dosage elevated the responses of splenic lymphocytes to the T-cell mitogens phytohemagglutinin (PHA) and concanavalin A (Con A), and resulted in higher PHA and Con A response ratios than were noted for age-matched controls. Conversely, groups of 3- or 6-month-old AKR mice, subjected to the same regimen but with 0.01-mg dosages, exhibited an apparent accelerated development of the leukemia and survived for significantly shorter periods. In general, splenic lymphocytes harvested from mice given a single 0.01-mg treatment of iodoacetate were not as reactive as were control cell cultures when exposed to the T-cell mitogens.