THE EFFECT OF INTRAARTICULAR HYDROCORTISONE INJECTION ON THE ARTICULAR-CARTILAGE OF RABBITS

We investigated the effect of hydrocortisone on the articular cartilag e of the knee in rabbits. 27 New Zealand white rabbits were injected i ntraarticularly with 25, 50 or 100 mg betamethasone acetate in 2 or 4 weakly intervals. Control animals were injected with normal saline and demonstrated no histological changes in the articular cartilage. Hydr ocortisone administration was associated with increased cell size, as well as an increased stain density in the cytoplasm surrounding vacuol es. In addition, loss of cell organelles was also observed. Nigh dose of hydrocortisone was associated with an obvious loss of cell shape an d distortion of the cell membrane and nucleus. The magnitude of histol ogical changes, found under light and electron microscopy, were propor tional to the amount of hydrocortisone injected. Our findings strongly indicate that intraarticular injection of hydrocortisone alters the s hape of articular cartilage chondrocytes, producing abnormal changes i n the cytoplasm and nucleus and leading to cell degeneration.