Effect of cortisone on cells at the bone-marrow interface

Area of Science:

• Bone Biology
• Cell Biology
• Pharmacology

Background:

• Osteopenia is a condition characterized by reduced bone mass.
• Cortisone acetate is a corticosteroid with known effects on bone metabolism.
• Marrow stromal cells play a crucial role in bone formation.

Purpose of the Study:

• To investigate the relationship between marrow fibroblast-like stromal cell proliferation and endosteal bone mineralization.
• To assess the impact of cortisone acetate on these parameters in an osteopenic rat model.

Main Methods:

• Cortisone acetate was administered to male rats.
• Marrow fibroblast colony-forming units (FCFU) were measured in vitro.
• Endosteal bone mineralization rate (EsMR) was assessed using tetracycline labeling in vivo.
• Measurements were taken at the femoral midshaft.

Main Results:

• Cortisone acetate treatment decreased both FCFU and EsMR.
• Following treatment, FCFU and EsMR normalized within the first week of recovery.
• A relapse in FCFU and EsMR was observed in the third week of recovery, indicating incomplete healing.
• Body weight changes did not correlate with these findings.

Conclusions:

• The fibroblast colony-forming unit (FCFU) count can serve as an indicator of endosteal osteoblast activity.
• Cortisone acetate negatively impacts bone mineralization and stromal cell function.
• The recovery process from cortisone-induced bone changes is complex and may not be complete.