ZHANG Deª²Zhi1, HU Yunª²Yu1, MENG Guoª²Lin1, YUAN Zhi1, BI Long1, LIU Danª²Ping2

    1Institute of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi¬ðan 710033, China, 2Department of Orthopaedics & Traumatology, First Affiliated Hospital, Jinzhou Medical Collage, Jinzhou 121001, China

    ¡¾Abstract¡¿ AIM: To observe the ultrastructure of intraosseous vascular endothelial damage and thrombosis in a glucocorticoid and LPS induced osteonecrosis in rabbits. METHODS: Sixteen New Zealand white rabbits were divided into osteonecrosis model group (n=10) and control group (n=6). In model group, LPS (30 ¦Ìg/kg) was given intravenously twice at an interval of 24 h, and then, 24 h after the second injection of LPS, dexamethasone (7.5 mg/kg) was given 5 times to the animals at an interval of 24 h. Saline infusion (0.5 ml/kg) was given in the control group. After pressurized perfusion with heparinª²saline and 10% formalin to hind limbs, the femoral head specimens were retrieved at week 8 postoperatively. Decalcified sections were prepared from half of the femoral heads, stained with hematoxylin and eosin, examined histologically for osteonecrosis. Undecalcified sections were prepared from the other half of the specimens, and then they were cleared of embedding material and were dried at criticalª²point and coated with goldª²palladium in a highª²vacuum evaporator. The sections were examined under scanning electron microscope for observing ultrastructural changes of the surface of microvascular endothelium in subchondral bone. RESULTS: The scanning electron microscope revealed irregular lumen, rough surface of microvascular endothelium or tamponade ......