Alteration of Knee Joint Connective Tissues during Contracture Formation in Spastic Rats after an Experimentally Induced Spinal Cord Injury

Abstract

This study was made to elucidate the changes in the periarticular connective tissue that can underlie the contracture after spasticity development. Sixteen Wistar rats underwent a spinal cord injury and 16 rats were either sham- or nonoperated. The periarticular connective tissue of the knee joint was assessed with histological, histomorphometric, immunohistochemical, and biochemical analyses. Histological results showed a smaller synovial intima, a dense subintimal and posterior joint capsule without fibrosis, and a disarranged posterior capsule in the spinal cord-injured knees with the flexion contracture. The synovial intima length was shortened only at the posterior capsule. Neither the distribution nor expression of type I and III collagen was affected. Contractures after spinal cord injuries are characterized by synovial intima adhesions. A dense and disarranged capsule may lead to joint stiffness. The alteration of periarticular connective tissues exhibits properties characteristic of the contracture after spasticity development.

Contrasting alteration patterns of different cartilage plates in knee articular cartilage after spinal cord injury in rats

“…[5][6][7]9 The eight SCI animals were anesthetized by intraperitoneal administration of 40 mg kg À1 sodium pentobarbital. After the spinal cord was exposed by a laminectomy of the T8 vertebra, it was completely transected at the level of T8.…”

“…Rectangles (30 mm deep and 400 mm long) were superimposed to the superficial and deep cartilage. Intense [5][6][7] Therefore, the FA cartilage corresponds to unapposed regions (no contact between cartilage surfaces) of the flexed knee. The FP, TA and TP regions are located at apposed regions (where the articular cartilages of two bones contact each other).…”

“…[1][2][3] The joints after SCI have been described as undergoing contractures, [4][5][6][7] osteoarthritis, 2 alterations of the periarticular connective tissue, 4,5 joint space narrowing and periarticular osteoporosis. 8 Several studies have also been reported the influence of SCI on the articular cartilage of the knee joint.…”

Remobilization Does Not Restore Immobilization-Induced Adhesion of Capsule and Restricted Joint Motion in Rat Knee Joints

“…Some researchers reported high levels of type I collagen and low levels of type III collagen in immobilized joints like ours (Matsumoto et al 2002). Others reported neither type I nor type III collagen changed in immobilized knee joints induced by spinal cord injury in immunohistochemical and biochemical studies (Moriyama et al 2007). In our previous study, despite the decreased expression levels of type I and III collagen mRNAs as judged by PCR, the protein levels of type I and III collagens remained unchanged after immobilization by immunohistochemistry and western blotting .…”

“…Though the importance of the joint capsule to the pathogenesis of the joint contracture is well accepted, the underlying changes within the joint capsule are not fully understood. Adhesions and shortening of the synovial membrane, atrophy and fibrosis of the capsule are known as structural changes Moriyama et al 2007), whereas decreased glycosaminoglycans and water content, and possibly accumulation of advanced glycation endproducts such as pentosidine are known as biochemical changes (Akeson et al 1977;Amiel et al 1985;Lee et al 2010). We reported in our previous study that immobilization of rat knee joints induced focal adhesion of the capsule to the opposing capsule and the underlying articular cartilage even at 2 weeks, and global adhesion of the capsule to the opposing capsule and obliteration of the joint space by loose connective tissues after 4 weeks of immobilization .…”