Clearnace of Fe59-labelled erythrocytes from normal and inflamed rabbit knee joints. I. Relationship to the anaemia of rheumatoid arthritis.

Exposure of human cartilage tissue to low concentrations of blood for a short period of time leads to prolonged cartilage damage: An in vitro study

“…In addition to type II collagen, proteoglycans are one of the main cartilage matrix components, both qualitatively and quantitatively (12). A 4-day period of exposure is assumed to be the natural time span of evacuation of blood from a joint (13,14), and at least 50% (v/v) blood in a synovial joint is the blood load expected to be present shortly after bleeding takes place (4). These in vitro findings were confirmed by in vivo animal studies (11,15,16).…”

Very rapid clearance after a joint bleed in the canine knee cannot prevent adverse effects on cartilage and synovial tissue

“…Previous clearance studies in rabbits 24,25 have shown a less quick clearance, varying from one-to two-third of the injected amount within 1 week. The contradiction with our quick clearance could originate from the limited discriminating ability of the technique used; the decrease in radioactivity signal upon injection of 59 Fe-labelled RBC was measured outside the joint using a probe, giving no information of the exact location of the radiolabeled RBC (synovial fluid, synovial tissue, or even peri-articular).…”

Clearance of Fe59-labelled erythrocytes from normal and inflamed rabbit knee joints. II. Autoradiographic and histological studies.

“…The method of preparing Fe59-labelled red cells and their introduction into the two joints has already been described (Muirden, 1969). The rabbits used for histological studies were killed 1, 3, 7, 14, and 42 days after injection of the erythrocytes.…”

“…At each stage sections of articular cartilage and meniscus failed to show iron on histological or autoradiographic studies. Muirden (1969) demonstrated that the radioactive clearance after intra-articular injections of Fe59labelled erythrocytes was slow, and the decay from joints inflamed by previous treatment with carragheenin was even more prolonged. Histological studies reported here indicate that red cells were prominent within the synovium up to 3 days after injection but were absent at Day 7 when surface counts showed that only one-third of the radioactivity had disappeared from the control joints.…”

“…The experimental model used was the arthritis induced in the rabbit's knee by injections of carragheenin (Gardner, 1960). Labelled red cells were injected into the inflamed and normal knee and a previous paper reports the clearance of Fe59 measured by surface counting and by liquid scintillation of ashed segments of membrane (Muirden, 1969). The distribution of iron within the joint tissues was estimated at various stages after injection by histological and autoradiographic techniques, and these studies form the basis of this report.…”