Effect Of ABC Research Articles

Effect of chondroitinase ABC on matrix metalloproteinases and inflammatory mediators produced by intervertebral disc of rabbit in vitro.

Lumbar intervertebral discs in rabbit were cultured in the presence of chondroitinase ABC. The matrix metalloproteinases (MMPs) and inflammatory mediators produced in culture media were then analyzed. To investigate the effect of chondroitinase ABC on MMPs and inflammatory mediators produced by intervertebral disc of rabbit in vitro. The chemonucleolytic effect of chondroitinase ABC is caused by the decrease in the chondroitin sulfate, hyaluronan, and protein content of the nucleus pulposus in rabbit. The reason for the decreases in protein content remains unclear. Anulus fibrosus and nucleus pulposus were cultured for 72 hours with or without chondroitinase ABC stimulated or not stimulated by interleukin-1 after preculture for 4 days. Subsequently, the MMPs (gelatinases MMP-2, MMP-9, and collagenase) and inflammatory mediators (prostaglandin E2 and nitric oxide) produced in the culture media were analyzed. In the anulus fibrosus chondroitinase ABC and interleukin-1 synergistically increased the collagenase activity, which was at a significantly higher level than the increment solely due to interleukin-1. In contrast, chondroitinase ABC counteracted the increase in nitric oxide production by interleukin-1. In the nucleus pulposus the collagenase and nitric oxide productions were not particularly affected by chondroitinase ABC and/or interleukin-1. In zymographic analysis MMP-2 was detected, but MMP-9 was only slightly detected in both tissues. There were no significant differences in both tissues for MMP-2 and prostaglandin E2 following incubation with or without chondroitinase ABC, whether stimulated by interleukin-1 or not. The collagenase activity in the anulus fibrosus was increased by chondroitinase ABC with interleukin-1. This finding may support the hypothesis that some proteolytic activities are involved in the chemonucleolytic process by chondroitinase ABC treatment.

Action of chondroitinase ABC on epidurally transplanted nucleus pulposus in the rabbit.

After autotransplanting the nucleus pulposus into the epidural space of rabbits, chondroitinase ABC was administered, and the effect of chondroitinase ABC was examined. To examine whether chondroitinase ABC accelerates resolution of the nucleus pulposus transplanted into the epidural space. No previous reports exist on the effect of chondroitinase ABC on the nucleus pulposus in the epidural space. In Study 1, autotransplantation of the nucleus pulposus into the epidural space was performed in rabbits. Histologic change was observed. In Study 2, dry weight, deoxyribonucleic acid content, and the amount of glycosaminoglycans of autotransplanted nucleus pulposus were quantified and compared with the respective values in the control group, chondroitinase-ABC-injected group, and phosphate-buffered saline-injected group. In Study 3, granulocytes obtained from the blood of a rabbit treated with chondroitinase ABC or phosphate-buffered saline were added to the nucleus pulposus taken from the same rabbit. In chondroitinase ABC group, inflammatory cells tended to infiltrate earlier than those in the control group (Study 1). The dry weight of recollected nucleus pulposus in the chondroitinase ABC group was significantly less than in the other groups. Deoxyribonucleic acid content in the nucleus pulposus tended to be larger in the chondroitinase ABC group, although no significant difference in content compared with that in the other groups was found. Regarding the residual glycosaminoglycans in the transplanted nucleus pulposus, the amount of chondroitin sulfate markedly decreased in the chondroitinase ABC group (Study 2). The number of granulocytes infiltrating the nucleus pulposus was distinctly large in the chondroitinase ABC group (Study 3). Chondroitinase ABC can enhance resolution of the nucleus pulposus in the epidural space.

Repair of Partial-Thickness Defects in Articular Cartilage

Partial-thickness defects evolving in mature articular cartilage do not heal spontaneously. This type of defect was created in the articular cartilage of adult rabbits and Yucatan minipigs, and the effects of chondroitinase ABC or trypsin, fibrin clots, and mitogenic growth factors on the healing process were examined histologically at intervals ranging from one to forty-eight weeks. The effect of chondroitinase ABC or trypsin was examined initially. Articular cartilage contains macromolecules, including proteoglycans, which render the surfaces of this tissue, and of partial-thickness defects within it, antiadhesive. Chondroitinase ABC digests the glycosaminoglycan chains of cartilage proteoglycans, and trypsin degrades their core proteins. To test the hypothesis that mesenchymal cells may be prevented from adhering to and migrating over the surfaces of partial-thickness defects by proteoglycans, we removed a superficial layer of these macromolecules from the surface of the defect with use of one of these enzymes. The treatment evoked an increase in the coverage of the defect surface with mesenchymal cells; when combined with the local application of a mitogenic growth factor (basic fibroblast growth factor, transforming growth factor-beta 1, epidermal growth factor, insulin-like growth factor-1, or growth hormone), the coverage was more extensive but mesenchymal cells did not extend into and completely fill the volume of the defect. When the surface of the defect was treated with chondroitinase ABC and the cavity of the defect was filled with a fibrin clot to furnish a matrix or scaffolding for the migration of cells therein, there was migration and proliferation of cells throughout the volume of the defect but at a low population density. Mesenchymal cells remodeled the deposited fibrin matrix, which was replaced by a loose fibrous connective tissue. When defects that had been treated with chondroitinase ABC were filled with a fibrin clot containing a mitogenic growth factor, mesenchymal cells filled the entire cavity of the defect, and the density of the cells was greatly increased, particularly when transforming growth factor-beta 1 was used. Histological studies revealed a continuous layer of mesenchymal cells extending from the synovial membrane across the superficial tangential zone of normal articular cartilage into the defect, indicating that the cells that were recruited for the repair process were of synovial origin. At forty-eight weeks, the entire cavity of the defect remained filled with a fibrous connective tissue.