Objective To evaluate the changes of GRP78 expression in the Spinal Cord of Ischemia/Reperfusion Injuried Rat.Methods Fifty five adult Wistar rats(250～300 g)were randomly divided into 2 groups as control group(n=5)and operation group(n=50).The spinal cord SCII model was established.The expression of GRP78 was detected in spinal cord tissue through immunohistochemistry(IHC)and Western blot analysis,and the neuronal apoptosis was detected through terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL)methods.Results The GRP78 expression was increased at 30 min of reperfusion,and peaked at 7 h,but began to decline at 11 h post-reperfusion,and reduced significantly at 23 h.The number of GRP78 positive neurons at 0.5,3,7,11 and 23 h groups was(19.4?1.34),(42.6?2.30),(82.4?2.07),(40.0?1.58)and(18.8?0.83),respectively and significantly higher than that of control group(P