AimTo detect the expression development of proapoptic molecule C/EBP homology protein(CHOP) mRNA and protein, and explore its effect on neuronal apoptosis after cerebral ischemia/reperfusion in rats.MethodsTransient focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) for 2 hours followed by reperfusion in sprague-dawley rats.Then，the expression of CHOP protein and/or mRNA were measured with methods of immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) at 1 h, 3 h, 6 h, 12 h and 24 h after reperfusion in cerebral cortex of rats.The neuronal apoptosis was detected by the method of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL).ResultsIn cerebral ischemia model group，the expression level of CHOP mRNA reached a peak at 12 h after reperfusion and that of CHOP protein reached a peak at 24 h after reperfusion，which paralleled with the tendency of neuronal apoptosis development.ConclusionCerebral ischemia reperfusion may induce CHOP expression. CHOP may play an important role in neuronal apoptosis induced by cerebral ischemia/reperfusion.