High‐Resolution NMR imaging of an antigen‐induced arthritis in the Rabbit Knee

Abstract

High-resolution, serial, spin-echo images were obtained for an antigen-induced knee arthritis in six rabbits. The animals were imaged prior to intra-articular challenge and at various time points up to 14 weeks after challenge. Extensive high-signal inflammatory changes were seen at Day 1 in the lymph node, capsule, and surrounding muscle. The muscle and lymph node response decreased rapidly after the first week. The capsule high-signal area reached a maximum at Day 10, but was still extensive at Day 39. The infrapatellar fat pad was replaced more slowly by high signal and the appearance of high signal in both the tibia and femur was a late change. Terminal histological examination showed that the capsule and fat pad high-signal areas corresponded to fibrous and synovial proliferation. The bone changes were a result of edema and cyst formation. The separation of the various time courses of the inflammatory changes may be of value in understanding the model and evaluating potential anti-arthritic drugs.

Comparison of magnetic resonance imaging (MRI) and histopathology in rabbit models of osteoarthritis and immune arthritis

“…Our observations in rabbit immune arthritis agree with other reports on the pattern of chondrocyte-mediated cartilage degradation [6] and synovial fibrosis [2,6]. The correlation between magnetic resonance properties and proteoglycan content in human cadaveric cartilage has been studied [-7, 8].…”

“…We have previously reported that cartilage thickness is reduced in magnetic resonance images (MRI) of rabbit knees injected intra-articularly with papain to degrade the cartilage extracellular proteoglycan matrix [1]. MRI of antigen-induced immune arthritis in rabbits [2] revealed fluids associated with inflammaCorrespondence to: Elizabeth M. O'Byrne, Ph.D., Research Department, Pharmaceuticals Division, Ciba-Geigy Corporation, Summit NJ 07901, USA tion and proliferative synovitis. MRI of mature rabbit articular cartilage showed a very short T2 [2].…”

“…MRI of antigen-induced immune arthritis in rabbits [2] revealed fluids associated with inflammaCorrespondence to: Elizabeth M. O'Byrne, Ph.D., Research Department, Pharmaceuticals Division, Ciba-Geigy Corporation, Summit NJ 07901, USA tion and proliferative synovitis. MRI of mature rabbit articular cartilage showed a very short T2 [2]. In the studies described here, we compared MRI and histopathotogical changes in rabbit models of surgically induced OA [3] and immune arthritis [4].…”

Analysis of water‐macromolecule proton magnetization transfer in articular cartilage

“…Many types of treatments have been studied, both pharmacological and surgical, but one of the most difficult problems associated with research in this field is the lack of noninvasive methods to measure the condition of the articular cartilage during disease progression. Several studies on NMR imaging of the knee joint have been published (1)(2)(3)(4) including one which correlated NMR images of the rabbit knee joint with histologic evaluation (5). Although gross soft tissue changes in the joint can be discerned with NMR techniques, it has been difficult to measure noninvasively the biochemical status of cartilage in vivo in order to make serial examinations of the same joint.…”

In vivo magnetic resonance methods in pharmaceutical research: current status and perspectives

“…MRI has been used to characterize a number of animal models of RA, such as adjuvant-induced RA in rats, [92][93][94][95] antigen-induced arthritis in rats 96,97 and rabbits, 98 interleukin-1 induced arthritis in rabbits, 99 and collagen type II induced arthritis in the rat. 100,101 In the last model the most distal joints (interphalangeal and metatarso-phalangeal joints) are affected prior to the proximal joints, 102 similar to the disease progression in man.…”