Ultrastructure of the articular cartilage after systemic administration of hydrocortisone in the rabbit: an electron microscopic study.

The acetabular cartilages from hip joints in adult rabbits receiving daily intramuscular injections of 1 or 5 mg hydrocortisone/kg body weight for periods of four or 12 weeks were studied by electron microscopy for quantitative analysis, nucleus to cell ratio, Golgi apparatus to cell ratio, rough endoplasmic reticulum to cell ratio and number of microvilli of chondrocytes and thickness of territorial matrix surrounding chondrocytes were obtained. Systemic steroid treatments decreased the volume of of rough endoplasmic reticulum and Golgi apparatus in chondrocytes, the number of microvilli, and the thickness of territorial matrix in matrix of the cartilage. These observations suggest that synthesis of proteoglycan and protein by chondrocytes is affected by steroid. These deleterious effects of steroid on cartilage begin with therapeutic dosages and progressively develop with increasing dosages of steroid or with increasing periods of time on steroid therapy.