The effect of intraarticular hydrocortisone injection on the articular cartilage of rabbits.

We investigated the effect of hydrocortisone on the articular cartilage of the knee in rabbits. 27 New Zealand white rabbits were injected intraarticularly with 25, 50 or 100 mg betamethasone acetate in 2 or 4 weekly intervals. Control animals were injected with normal saline and demonstrated no histological changes in the articular cartilage. Hydrocortisone administration was associated with increased cell size, as well as an increased stain density in the cytoplasm surrounding vacuoles. In addition, loss of cell organelles was also observed. High dose of hydrocortisone was associated with an obvious loss of cell shape and distortion of the cell membrane and nucleus. The magnitude of histological changes, found under light and electron microscopy, were proportional to the amount of hydrocortisone injected. Our findings strongly indicate that intraarticular injection of hydrocortisone alters the shape of articular cartilage chondrocytes, producing abnormal changes in the cytoplasm and nucleus and leading to cell degeneration.