Objective: To analyze the role of Caspase 3 in neuronal apoptosis after acute brain injury. Methods: Experiments were carried out with rat diffuse brain trauma model. The neuronal DNA injury in cortex and hippocampus was observed by TUNEL stain. The mRNA and protein expressions and enzyme activation of Caspase 3 were observed by Northern blot, in situ hybridization, immunohistochemistry stain and Western blot, respectively. Special Caspase 3 enzyme inhibitor was used to observe the therapeutic effect.Results: TUNEL positive neurons appeared 2 hours after severe trauma, peaked at 1 day and lasted for 7 days. Northern blot showed that the Caspase 3 mRNA expression was increased and peaked at 1 day, about twice higher than the control. In the area of cortex and hippocampus, positive mRNA staining neurons appeared most distinct on one day. With the antibody for Caspase 3 P20 subunit, the active Caspase 3 expression peaked at 1 3 days. The electrophoresis band of PARP degradation would be seen by Western blot. Caspase 3 enzyme inhibitor could reduce apoptotic neuronal death without any effect on Caspase 3 P20 subunit expression. Conclusions: After brain trauma, Caspase 3 mRNA and protein expressions and enzyme activation are enhanced in combination with neuronal apoptosis. Special Caspase 3 enzyme inhibitor can apparently decrease the neuronal apoptosis.
