Influence of acute ethanol intoxication on neuronal apoptosis and Bcl-2 protein expression after severe traumatic brain injury in rats

Objective: To study the influence and mechanism of acute ethanol intoxication (AEI) on rat neuronal apoptosis after severe traumatic brain injury (TBI). Methods: Ninety-six Sprague-Dawley rats were randomly divided into four groups: normal control, AEI-only, TBI-only and TBI+AEI (n=24 for each). Severe TBI model was developed according to Feeney's method. Rats in TBI+AEI group were firstly subjected to AEI, and then suffered head trauma. In each group, animals were sacrificed at 6 h, 24 h, 72 h, and 168 h after TBI. The level of neuronal apoptosis and the expression of Bcl-2 protein were determined by TUNEL assay and immunohistochemical method, respectively. Results: Apoptotic cells mainly distributed in the cortex and white matter around the damaged area. Neuronal apoptosis significantly increased at 6 h after trauma and peaked at 72 h. Both the level of neuronal apoptosis and expression of Bcl-2 protein in TBI-only group and TBI+AEI group were higher than those in control group (P<0.05). Compared with TBI-only group, the two indexes were much higher in TBI+AEI group at all time points (P<0.05). Conclusion: Our findings suggest that AEI can increase neuronal apoptosis after severe TBI.