Histochemistry of synovium in experimental haemarthrosis in the rabbit

Experimental haemarthrosis in rhesus monkeys: morphometric, biochemical and metabolic analyses

The effects of a single episode of massive haemarthrosis in rhesus monkeys were studied. Autologous whole blood was injected into a femorotibial joint of 16 anaesthetized monkeys, equally divided into four groups and killed 7 days, 2, 3 and 6 months post-injection (PI). Synovial membrane and femoral articular cartilage were analysed morphometrically and articular cartilage was further analysed biochemically and metabolically. At 7 days PI, morphometric evaluation revealed a significant increase (P less than 0.05) in synovial membrane cellularity and synovial intimal thickness of injected joints versus control joints. This change was no longer evident 2 months PI. There was also an overall (n = 16) significant increase (P less than 0.05) in femoral articular cartilage cellularity in injected joints. The average chondrocyte lacuna area of injected joints was not statistically different from the control joints. Biochemical analyses of femoral articular cartilage revealed a significant decrease in hexosamine concentration (P less than 0.05) of injected joints. There was no significant difference between the injected and control joints in hydroxyproline or total protein concentration. Metabolic analyses revealed a significant increase (P less than 0.05) in cartilage collagenous protein production by injected joints compared with control joints. There were no significant differences in cartilage or secreted total protein production between injected and control joints. There were also no significant differences in cartilage or secreted proteoglycan production between joints. Morphometric evaluation of articular tissues following massive haemarthrosis has quantified a temporary hyperplastic reaction. A significant decrease in cartilage hexosamine concentration in haemarthrotic joints suggests this is a crucial biochemical event in the pathogenesis of blood-induced cartilage destruction.

Ultrastructural changes in synovium and cartilage in experimental hemarthrosis in dogs

This paper reports electron-microscopic findings in synovium and cartilage in experimental hemarthrosis in dogs. The results are correlated with the total amount of glycosaminoglycans in the cartilage matrix, measured by the fixed-charge density method. Very early, changes are seen in the synoviocytes, similar to synovitis, and especially phagocytosis of iron-containing particles forming secondary lysosomes or siderosomes. Siderosomes are also a constant feature seen in the chondrocytes, together with changes in the rough endoplasmic reticulum and in the glycogen content, correlating with the changes in the ground substance.

Macroscopic, microscopic and ultrastructural findings in experimental haemarthrosis of rhesus monkeys

The effects of a single episode of massive haemarthrosis in rhesus monkeys were studied morphologically. Autologous whole blood was injected into a femorotibial joint of 16 anaesthetized monkeys, equally divided into four groups and killed 7 days, 2, 3 and 6 months post injection (PI). Synovial membrane and articular cartilage were examined for macroscopic, microscopic and ultrastructural changes. Haemarthrosis was only evident in one monkey by 7 days PI. Slight yellow-brown discoloration of synovium and cartilage was evident in groups killed early after injection. Histologically, a hyperplastic and inflammatory reaction was present in the synovium at 7 days PI. Ultrastructural examination of synoviocytes in this group revealed numerous cytoplasmic vacuoles and prominent microplicae compatible with increased phagocytic activity. Erythrophagocytosis by synoviocytes was observed by light microscopy and confirmed by transmission EM. Results of scanning EM suggested that red cells might also pass through the synovial intima. Transmission EM also revealed mild degenerative changes in superficial chondrocytes. Rhesus monkeys reacted morphologically to haemarthrosis in the same way as dogs and rabbits, with mild morphological changes that resolved by 2 months PI.

Early changes in the ground substance of articular cartilage in experimental hemarthrosis in dogs, measured by the fixed-charge density method

This work presents early findings in the articular cartilage of dog knees in experimental hemarthrosis produced by injections of whole blood, red blood cells, white blood cells, serum, and iron citrate. The effect of coagulation and synovectomy was also studied. The fixed-charge density determination has proved to be a reliable, easy, and rapid method for finding - very early in the process - quantitative changes in cartilage ground substance. Changes in the proteoglycan (PG) content of articular cartilage matrix take place after a certain duration and intensity of hemarthrosis, after which loss of ground substance is repeatedly and consistently observed. After some time (6 months, and culminating after 14 months in our study) a reparative reaction takes place. In experimental hemarthrosis of longer duration this healing reaction seems to be overwhelmed by the degrading forces, with probable further evolution to the full-blown pathology. The cellular components of the blood seem to play a major role. Prophylactic synovectomy seems to be effective only in preventing further bleeding. Coagulation of the intra-articular blood does not alter its deleterious effect. Finally, a small iron ligand alone, although proven in vitro to penetrate into cartilage, is not capable of producing matrix changes.

[Hemarthrosis and cruciate ligaments - biomechanical studies. 1]

Experimental studies on animals were conducted in order to investigate the influence exerted by a posttraumatic hemarthrosis upon the cruciate ligaments. The cruciate ligaments used in this experimentation had partly been exposed only to a posttraumatic hemarthrosis, the other part showed an additional lesion of the synovial sheath. Further investigations were carried out in order to find out if the effect of the hemarthrosis is modified by a plaster immobilization of the concerned extremity. In a comparative study, cruciate ligaments which had been exposed to hemarthrosis for different periods of time and normal cruciate ligaments were submitted to mechanical tension which was exerted until rupture. By means of extensive pre-experiments it was possible to define the practical execution, the storage of the removed cruciate ligament preparations, and the general mechanical behavior of cruciate ligaments in rabbits. The study showed that all cruciate ligaments exposed to hemarthrosis presented at least a temporary significant reduction of their mechanical loading capacity. This reduction was even more significant in case of an additional lesion of the synovial sheath. In the first case, a restitution of the normal loading capacity was observed after 8 to 12 weeks, in the second case (additional lesion of the synovial sheath) after 12 to 16 weeks. These results were not improved by a plaster immobilization of the concerned extremity; on the contrary this caused rather a negative tendency.

Articular cartilage in corn oil-induced lipoarthrosis

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