Induction of Caspase-3 Gene in Neuronal Apoptosis After Transient Focal Cerebral Ischemia

Aim:Since caspase members have been identified as effectors of apoptosis and caspase-3 is the most key protease,the role of caspase-3 was further explored in neuronal cell death after transient cerebral ischemia.Methods:To determine whether caspase-3 serves to regulate neuronal death after various ischemia/reperfusion time,108 adult Wistar rats were subjected to 30 min or 2 h of transient focal cerebral ischemia induced by intraluminal blockade of the left middle cerebral artery followed by 1～48 h of reperfusion,Caspase-3 mRNA expression was examined by both PT-PCR and in situ hybridization analyses.Terminal deoxynucleotidyltranfer-ase (TdT)-mediated dUTP-flourescein nick end-labeling (TUNEL) staining was performed for the detection of apoptosis.Results:Caspase-3 mRNA was constitutively expressed in rat brain.At 6-48 h after 30 min of occlusion and 1-48 h after 2 h of occlusion,caspase-3 mRNA was markedly induced in the inner boundary zone of the infarction,which became more pronounced with ischemia- or reperfusion-time,with a peak at 24-48 h of reperfusion.The temporal and spatial profile of neuronal apoptosis was consistent with those of caspase-3 gene expression.Conclusion:These observations strongly support a key role for caspase-3 in neuronal apoptosis and ischemic/reperfusion brain injury and suggest that caspase-3 inhibitors may provide a promising opportunity for stroke and other neurological disorders in which apoptosis is prominent.