The histological and histochemical changes in the meniscus of the adult
rabbit were investigated after eight weekly intra-articular injections of
prednisolone acetate. Light microscopic changes included decreased
intensity of staining with either safranin O or toluidine blue O,
hypocellularity, fibrillation, and tearing of the meniscus. Transmission
electron-microscopic examination demonstrated a marked decrease of
intracytoplasmic organelles and immature collagen fibrils, separation and
deformation of collagen fibers, and the loss of safranin O-positive
stellate granules in the pericellular space and between collagen fibers.
CLINICAL RELEVANCE: The results of this study, although it was done in
rabbits, demonstrate the possible deleterious effects of repeated
intra-articular injections of corticosteroid on the human meniscus.