• 1Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology;;
  • 2Department of Organ Imaging and Radiology, the Chinese University of Hong Kong, Hong Kong SAR, P. R. China;
Steroid-associated osteonecrosis; Intravascular thrombus occlusion; Extravascular l i piddeposition; Blood perfusion; Ischemia
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【Abstract】 Objective The present study employed both static and dynamic imaging modal ities to study both
intra- and extravascular events attributing to steroid-associated osteonecrosis (ON) using an experimental protocol with a single low-dose l i ppolysaccharide (LPS) injection and subsequently three injections of high-dose methylprednisolone (MPS). Methods Fourteen 28-week-old male New Zealand white rabbits received one intravenous injection of LPS (10 μg/ kg). After 24 hours, three injections of 20 mg/kg of MPS were given intramuscularly at a time interval of 24 hours. Additional 6 rabbits were used as controls. Dynamic MRI was performed on bilateral femora for local intraosseous perfusion before and after LPS injection. Blood samples were collected for haematological examinations before and after LPS injection. Bilateral femora were dissected and decalcified for microCT-based microangiography. ON lesion, intravascular thrombus and extravascular marrow fat cell size were examined histopathologically. Results Intravascular thrombus was observed in all ON rabbits. Extravascular marrow fat cell size was significantly increased in ON rabbits than that of the controls (P  lt; 0.05). Compared to basel ine, a significant decrease in ratio of tissue-type-plasminogen-activator/plasminogen-activator inhibitor 1,
activated-partial- thromboplatin-time, and a significant increase in ratio of low-density-l ipoprotein/high-density-l ipoprotein were only found in ON rabbits (P  lt; 0.05). Dynamic MRI showed a significant decrease in the perfusion index ‘maximum enhancement’ in the ON rabbits (P  lt; 0.05) and microCT-based microangiography showed blocked stem vessels in ON samples.Overall, 93% of the rabbits (13/14) developed ON and no rabbits died throughout the experiment period. Conclusion Bothintra- and extravascular events were found attributing to the steroid- associated ON based on our experimental protocol with a single low-dose LPS injection and subsequent three injections of high-dose MPS. Both high ON incidence and no mortal ity in rabbits treated with this inductive protocol suggested its effectiveness for future studies on evaluation of therapeutic efficacy of interventions developed for prevention of steroid-associated ON.

Citation： QIN Ling,ZHANG Ge,SHENG Hui,YEUNG Kawai,YEUNG Hiuyan,CHAN Chunwai,CHEUNG Winghoi,GRIFFITH James,LEUNG Kwoksui. MULTIPLE BIOIMAGING MODALITIES IN EVALUATION OF AN EXPERIMENTAL OSTEONECROSIS MODELINDUCED BY A COMBINATION OF LIPOPOLYSACCHARIDE AND METHYLPREDNISOLONE. Chinese Journal of Reparative and Reconstructive Surgery, 2008, 22(3): 258-264. doi: Copy