Early and late apoptosis protein expression (Bcl-2, BAX and p53) in traumatic brachial plexus injury

OBJECTIVES: This research aims to analyze the expression of pro-apoptotic proteins (Bax, p53) and anti-apoptotic protein (Bcl-2) in the nerve roots of the brachial plexus following traumatic brachial plexus injury (TBPI) in the early and late stage. METHODS: A total of 30 biopsy samples were taken from the proximal stump of the postganglionic nerve roots of the TBPI patients’ brachial plexus from January 2018 until September 2019. The samples were taken from patients within six months of trauma (early stage, group A) and more than six months following trauma (late stage, group B). Bcl-2, Bax, and p53 expressions in each group were measured and compared. RESULTS: We found significant differences in the Bcl-2 (p=0.04), Bax (p<0.0001), p53 (p<0.0001) expressions between group A and B. The Bcl-2/Bax expression ratio in group A and B was 2.26 and 0.22, respectively. Meanwhile, the Bcl-2/p53 expression ratio in group A and B was 1.64 and 0.23, respectively. CONCLUSION: Apoptosis is inhibited by Bcl-2 activities in the early stage following trauma. In the late stage, a significant decrease of Bcl-2 coupled with a substantial increase of Bax and p53 indicates a continuation of the apoptotic process.