A novel translocator protein 18kDa ligand, ZBD-2, exerts neuroprotective effects against acute spinal cord injury

Traumatic spinal cord injury (SCI) happens accidently and often leads to motor dysfunction due to a series of biochemical and pathological events and damage, either temporarily or permanently. Translocator protein 18 (TSPO) has been found to be involved in the synthesis of endogenous neurosteroids which have multiple effects on neurons, but the internal mechanisms are not clear. N-benzyl-N-ethyl-2-(7,8-oxo-2-phenyl-9H-purin-9-yl) acetamide (ZBD-2), a newly reported ligand of TSPO, shows some neuroprotective effect against focal cerebral ischemia in vivo and NMDA-induced neurotoxicity in vitro. The present study aims to examine the role of ZBD-2 in SCI mice and elucidate the underlying molecular mechanisms. The SCI model was established by crushing spinal cord. ZBD-2 (10mg/kg) significantly enhanced the hindlimb locomotor functions after SCI and decreased the tissue damage and conserved the white matter of the spinal cord. High-dose ZBD-2 alleviated the oxidative stress induced by SCI and regulated the imbalance between NR2B-containing NMDA and GABA receptors by increasing the levels of GAD67 in the spinal cord of SCI mice. Additionally, ZBD-2 (10mg/kg) increased phosphorylated Akt (p-Akt) and decreased the ratio of Bax/Bcl-2. These results demonstrate that ZBD-2 performs neuroprotection against SCI through regulating the synaptic transmission and the PI3K/AKT signaling pathway.