52, 215 mg kg - 1 d - 1

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1 mg kg - 1 d / ; ; Changes of blood vessels in glucocorticoid2induced avascular necrosis of femoral head in rabbits ZHOU Qiang LI Qihong YANGLiu et al. Department of Orthopaedics Southwest Hospital Third Military Medical Univer2 sity Chongqing China. Abstract Objective To evaluate the effects of fatty tamponade in medullary cavity ( serious in2 tramedullary fatty infiltration) on the changes of blood vessels in femoral heads during the pathological process of glucocorticoid( GC)2induced avascular necrosis (AVM) of the femoral heads. Methods The animal model of AVN was established with injection of dexamethasone(dex) at a high dose of 215 mg kg - 1 d - 1 in rabbits. Histopathological and morphological changes of blood vessels in the femoral heads were investigated during GC2 treatment and after the cessation scanning electron microscope light microscope and image analysis. Results At the 2nd week of DEX2treatment the fatty tamponade in the medullary cavity appeared in the femoral heads. In2 tramedullary vascular sinusoids were pressed by an excess of lipocytes and became narrow. The impressions of lipocytes on the surface of vascular sinusoids were definitely displayed on the vascular casts and ink2perfused slides of the femoral heads. These changes were pronounced with the prolongation of the treatment and the vascular sinu2 soids gradually lost their characteristics. Image analysis showed that the vascular area in the femoral heads continu2 ously decreased. At the 8th week the effects of fatty tamponade were the most marked. Intramedullary vessels be2 came very sparse and the vascular area decreased to 1/ 4 of the controls. At the 6th week after the GC2treatment cessation intramedullary fatty infiltration still existed. The blood vessels were fine and sparse and the structural features of vascular sinusoids disappeared in the load2bearing regions of the femoral heads. At the 4th week typi2 cal osteonecrosis focuses appeared in the femoral heads. The focuses became larger and the degree of osteonecrosis was increasing with the time of experiment. Conclusion The fatty tamponade in the medullary cavity is one of the important pathological factors causing ischemic damage to the femoral heads and plays an important role in the early stage of GC2induced AVN. Key words Femur head necrosis ; Microcirculation ; Glucocorticoids (glucocorticoid GC) ( avascular necrosis of GC AVN femoral head AVN) GC ( : (193) ) GC AVN : ( ) ( ) [1 2 ]

2 ( 1. : DEX 2 2 : ( n = 42) : mg/ kg (Dexamethasone DEX) 8 (1) ; ( n = 10) : DEX 8 1. : DEX 2 2. : 20 DEX 6 min 215 % 10 % 10 % ; HE 250m 3. :: :DEX 2 ( ) % 4 ( ) % 6 ( ) % 8 ( ) % DEX 2 ( ) % 6 ( ) % ; ( ) % ( P < 0101) 14 ( 6 ) 4. :2 10 % 1. : (1) : HE (2) :DEX ( %) 4 ( gx s) SPMR DEX DEX 2 ) kg DEX 4 6 (2) ; 2. : 3. (3) 68 (4) DEX 2 ; DEX 6 2

3 214 (5) GC 2. :DEX ( ) [8 ] : DEX DEX ; ( P < 0101) DEX 8 8 1/ 4 1. : DEX 6 GC 2. : (1) 2 (2) :DEX 4 (6) ;DEX 6 8 GC ; DEX 2 (7) ;DEX 6 6 (8) GC AVN 8 GC 6 GC AVN [325 ] ( ) ( 6 ) [1 6 7 ] GC 1/ 4 DEX GC AVN GC DEX 2 2 AVN

4 215 AVN ( ) 1 Arlet J. Nontraumatic avascular necrosis of the femoral head :past present and future. Clin Orthop 1992 (277) : Mont MA Hungerford DS Maryland B. Current concepts review : non2 traumatic avascular necrosis of the femoral head.j Bone Joint Surg(Am) : Hungerford DS Lennox DW. The importance of increased intraosseous pressure in the development of osteonecrosis of the femoral head :implica2 tions for treatment. Orthop Clin North Am : Wang GJ Sweet DE Reger SI et al. Fat2cell changes as a mechanism of avascular necrosis of the femoral head in cortisone2treated rabbits.j Bone Joint Surg(Am) : Solomon L. Mechanisms of idiopathic osteonecrosis. Orthop Clin North Am : Jones JP Jr. Fat embolism and osteonecrosis. Orthop Clin North Am : Warner JJP Philip JH Brodsky GL et al. Studies of nontraumatic os2 teonecrosis manometirc and histologic studies of the femoral head after chronic steroid treatment :an experimental study in rabbits. Clin Orthop 1987 (225) : Lockin RM Williamson MC Beresford JN et al. In vitro effects of growth factors and dexamethasone on rat marrow stromal cells. Clin Orthop 1995 (313) : ( : ) ( : ) [3 ] [ ] ; cm 315 cm Zellballen : : NSE ( + ) SGN ( + ) CGA ( + ) a - FP ( - ) AE1/ AE3 ( - ) 2 1 Heppleston AG. A caroid2body like tumor in the lung. J Pathol Bacteriol : Heppleston [1 ] : [ ] 4 3. :5. : : ( : ) ( : )

5 ( 212 ) 1 DEX 4 ( ) ( ) HE DEX 8 ( ) ( ) HE DEX 4 ( ) ( ) + HE DEX 8 ( ) ( ) ( ) 40 5 DEX 6 ( ) ( ) ( ) 40 6 DEX 4 ( ) SEM DEX 2 ( ) ( ) SEM DEX 6 ( ) SEM