Abstract
Introduction
The objective of this study was to investigate the incidence of steroid-induced osteonecrosis (ON) among male and female rabbits.
Methods
Forty-seven adult rabbits (male, n = 24; female, n = 23) were injected once intramuscularly into the right gluteus medius muscle with 20 mg/kg of methylprednisolone acetate. Hematological examinations were performed just before and at 1 and 2 weeks after the corticosteroid injection. Two weeks after the injection, both femora and humeri were histopathologically examined for the presence of ON, and the bone marrow fat cells were examined morphologically.
Results
Sixteen of 24 male rabbits (66.7%) developed ON, with only 5 of 23 female rabbits (21.7%) developing ON. There was a significant difference in the rate of incidence of osteonecrosis between male and female rabbits (p = 0.0032). Hematologically, at 1 week after the corticosteroid injection, both the mean low-density lipoprotein (LDL) and the ratio of LDL cholesterol to high-density lipoprotein (HDL) cholesterol in the male rabbits were significantly higher than those in the female rabbits (p = 0.0001 for both comparisons). The bone marrow fat cells of the male rabbits (61.5 +- 5.6 μm) were significantly larger than those of the female rabbits (58.9 +- 3.7 μm) (p = 0.0102).
Conclusion
This study indicates that gender may be an important factor in considering the pathogenesis of corticosteroid-induced ON.
