Objectives: Previous studies have demonstrated that the inhibition of autophagy could reduce traumatic brain injury (TBI)-induced cell injury and attenuate behavioural outcomes. Meanwhile, synaptically released zinc translocation is found in the hippocampus of rats, and excessive release of chelatable zinc from excitatory synaptic vesicles is involved in the pathophysiological processes of TBI. We speculated that the release of zinc is closely connected with autophagy and that treatment with the zinc chelator N,N,N',N'-tetrakis-(2-pyridylmethyl) ethylenediamine (TPEN) could attenuate autophagy and thus improve histologic outcomes after TBI in rats.
Methods: Rats were randomly divided into three groups: sham group, CCI+vehicle group and CCI+TPEN group. TPEN (20 mg/kg/12 h, i.p) or vehicle (DMSO) was injected into the rats immediately after TBI, then given twice a day until the animals were sacrificed. Morphological changes associated with autophagy were tested by TEM. Zinc autometallography staining was used to evaluate chelatable zinc accumulation. Western blot analysis was used to detect protein expression.
Results: In our study, we found that treatment with TPEN reduced zinc translocation, reduced excitotoxicity and also partially reduced levels of LC3-II, Beclin1 and the ratio of Beclin-1/Bcl-2 in injured hippocampal neurons of rats, partially improving histologic outcomes after TBI.
Conclusion: These data show that the zinc chelator TPEN plays a protective role in TBI, suggesting the possible involvement of autophagy.
Keywords: TPEN; autophagy; traumatic brain injury; zinc translocation.
© 2018 by the Association of Clinical Scientists, Inc.