Activation of SIRT3 / PRDX5 signaling inhibits apoptosis after acute spinal cord injury in mice

Spinal cord injury (SCI), a traumatic condition affecting the nervous system, constitutes an orthopedic emergency that is closely associated with a significantly elevated disability rate. Excessive apoptosis not only hinders neuronal repair, but also exacerbates the deterioration of the local microenvironment, thereby impeding the treatment of SCI. The present study comprehensively investigated the dynamic expression of mitochondrial deacetylase sirtuin 3 (SIRT3) in a murine model of SCI. Activation of SIRT3 with the natural agonist honokiol (HKL) facilitated neurological functional recovery by mitigating neuronal apoptosis and oxidative stress injury in vivo. Mechanistically, through comparative analysis of transcriptome alterations after global deletion of SIRT3 (Sirt3^-/-), mitochondrion localized protein peroxidase peroxiredoxin 5 (PRDX5) was identified as the direct downstream effector of SIRT3. Spatially, SIRT3 and PRDX5 were colocalized within neurons in the anterior horn of the spinal cord. Genetic silencing of PRDX5 partially attenuated the protective effects of SIRT3 against neuronal apoptosis and the promotion of functional recovery. Overall, this study is the first to reveal the pivotal role of the SIRT3PRDX5 axis in modulating neuronal apoptosis after SCI, and thus offers a novel perspective on the restoration of function after SCI.