Correlation Research on the Protein Expression (p75ntr, Bax, Bcl-2, and Caspase-3) and Cortical Neuron Apoptosis Following Mechanical Injury in Rat.

OBJECTIVE:In this study, we aimed to survey the role of p75NTR, bax, bcl-2, and caspase-3 in the progress of traumatic brain injury (TBI).MATERIALS AND METHODS:A mechanical trauma model of vital neurons was established by putting external pressure, contusion and centrifugal acceleration on neurons. Morphological change, survival rate, assay of LDH activity, and apoptosis rate were evaluated for mild, medium and severe injury models. The expression of bax, bcl-2, caspase-3, p75NTR, p75NTR mRNA was determined by immunohistochemistry, immunofluorescence, Western blotting and RT-PCR.RESULTS:There was a transient high level Bcl-2 protein within 2 h after injury to increase neuronal tolerance and avoid apoptosis. Subsequently p75NTR, Bax/Bcl-2, and Caspase-3 reached their peaks from 48 to 72 h accompanied with the maximum apoptosis rate.CONCLUSIONS:Our results suggest that apoptosis ratio in varying degree injury groups are correlated with the expression level of p75NTRmRNA, p75NTR, Caspase-3, Bax/Bcl-2 ratio.