Mechanisms of glucocorticoid-induced growth retardation: impairment of cartilage mineralization.

Immature female mice were treated with daily doses of triamcinolone diacetate. Using histochemical and fluorescent methods, the mineralization pattern of the proximal epiphyseal plate of the humerus was studied at various intervals. Following 1 injection, a noticeable decrease was noted in the oxytetracycline incorporation at the mineralizing zone of the growth plate. By the 10th injection, the mineralization process was almost totally arrested. Marked accumulation of phospholipids appeared in experimental plates concomitantly with a lack of acidic glycosaminoglycans' synthesis as well as degradation. Chondroclastic activity was also inhibited resulting in an increased number of hypertrophic chondrocytes at the mineralization zone. It is suggested that the hormone's antianabolic effect led to an impairment in the activity of the chondrocytes' hydrolytic enzymes and thereby interfered with the maturation of the matrix, a prerequisite phase for normal mineralization.