EXPRESSION
OF VASCULAR ENDOTHELIAL GROWTH FACTOR DURING DEVELOPMENT OF STEROID-INDUCED
OSTEONECROSIS: AN EXPERIMENTAL STUDY IN RABBITS
Sinichi
Yagishita 1, Tadami Matsumoto 2, Takeshi Horii 1, Tamon Kabata 1, Mitsuru
Nishino 2, Tomoko Futami 2, Tomohiko Wakayama 3, Osamu Amano 3, Shoichi
Iseki 3, and Katsuro Tomita 1
1) Kanazawa University, Department of Orthopaedic Surgery, Kanazawa,
Japan
2) Kanazawa Medical University, Department of Orthopaedic Surgery, Ishikawa,
Japan
3) Kanazawa University, Department of Anatomy (I), Kanazawa, Japan
Introduction: We investigated the VEGF expression in a rabbit experimental model to clarify the onset of ischemic events in steroid-induced osteonecrosis (ON).
Methods: Mature Japanese white rabbits were divided into 6 treatment groups received a single intramuscular injection of methylprednisolone acetate and an untreated control group. They were sacrificed at different time points, and tissue samples were obtained from the femur. The development of ON and the expression of VEGF were examined by histopathology, immunohistochemistry, Northern blot and Western blot analyses.
Results: ON was observed in the proximal femur 5 days after the steroid treatments. VEGF expression was accompanied by development of ON. The VEGF positive cells were frequently located in the area surrounding ON. The level of VEGF- mRNA and VEGF expression peaked at 3 days after the steroid treatment.
Discussion &
Conclusion: These results suggest that the onset of the ischemic
events that causes ON occurs soon after the initial steroid treatment.