An experimental observation on delayed neuronal death after acute brain trauma

Objective To observe pathological forms and course of de layed neuronal death after acute brain injury. Methods The ex periments were mainly based on rat diffuse brain injury model after acute brain injury. Hippocampal neurons from cultured newborn rat were tested for delayed ne uronal death in vitro. The conditions of tissue and cell injury were observed un der microscopy and electromicroscopy. The neuronal DNA injury in cortex and hipp ocampal was observed by DNA-Ladder and TUNEL stain. Results H istological examination showed that the neurons presented degenerative change; e lectromicroscopic examination showed that the neuronal apoptosis and necrosis wo uld be seen in the cortex and hippocampus and was the most serious after 24 hour s. Gradient electrophoresis from DNA Ladder would be seen and was the most disti nct at 24 hours after severe injury. Most neurons with positive TUNEL stain repr esented neuronal apoptotic change 2 hours after injury. In vitro, 24 hours after neuron thrust injury, some neurons died from necrosis and apoptosis when the no rmal neuron was cultured by the culture liquid from the injured neuron. Conclusions Delayed brain injury happens after acute brain injury d ue to lot of second injury factors, and exhibites mainly necrosis, apoptosis and longer duration of apoptosis.