Spread of gold injected into the joints of healthy rabbits

This study shows that after intra-articular injection, aurothiomalate and colloidal gold of small (200 A) particle size were rapidly absorbed from joints while the larger, 300 A, particle size colloidal radioactive gold could not be found outside them. Larger particle size suspensions seem therefore more likely to remain localised in the joint and its lining synovium after intra-articular injection, the systemic absorption from the joint cavity diminishing with increasing particle size. It was also found that the intra-articular injection of small amounts of aurothiomalate, of colloidal gold and of colloidal radioactive gold produces identical degenerative lesions in the lining cells of the proximal convoluted tubules of the kidneys. These lesions were always found, although gold particles were demonstrated only in sampled kidney tissues of the animals injected with the soluble gold preparation whereas no gold could be detected in the tissues of animals injected with colloidal non-radioactive or radioactive gold. Electron microscopic evidence is presented to suggest the possibility that the mitochondria are the "target" organelles of the gold-induced cellular damage. Mitochondrial damage was demonstrated in liver and spleen in addition to the already described kidney damage. The correlation between structure and function of the mitochondrial changes is not clear, and ionic shifts may be both a cause and a result of damage.