Changes in the vesicular zinc pattern following traumatic brain injury.
The present study aims at evaluating the significance of zinc ions on the development of brain damage in a model of traumatic brain injury (TBI). The zinc ion specific autometallographic technique, the ZnSe(AMG) method, using silver enhancement of in vivo-captured zinc ions bound in zinc-selenium nanocrystals was applied to follow changes in the vesicular zinc pattern. Balb/c mice, ZnT3 knockout (ZnT3-Ko) mice, a mouse genetically knocked out for the protein ZnT3 responsible for sequestering zinc into synaptic vesicles, and littermates from the genetically un-manipulated mother type mice, wild type (Wt), were used. The Wt and the Balb/c mice exhibited instantaneously a boost in the zinc staining adjacent to the lesion involving all six neocortical layers. Ultra-structural analyses revealed that the in vivo created ZnSe nanocrystals were still confined to the vesicles of the zinc-enriched (ZEN) neurons in the neuropil. No differences between the Balb/c and Wt mice were seen at any time points. In the ZnT3-Ko mice the ZEN terminals stayed void of AMG grains, but a number of neuronal somata around the lesion became loaded with ZnSe nanocrystals. These silver-enhanced ZnSe nanocrystals were confined to the cytoplasm of the somata and their proximal dendrites. No such soma staining was seen in the Wt or Balb/c mice. We speculate that vesicular zinc may not contribute to neuronal damage following TBI.
Doering
P
P
Department of Neurobiology, Institute of Anatomy, University of Aarhus, DK-8000, Aarhus C, Denmark. pdj@neuro.au.dk <pdj@neuro.au.dk>
Danscher
G
G
Larsen
A
A
Bruhn
M
M
Søndergaard
C
C
Stoltenberg
M
M
D000818:Animals; D001930:Brain Injuries / Q000378:metabolism* / Q000473:pathology*; D002352:Carrier Proteins; D027682:Cation Transport Proteins; D004195:Disease Models, Animal; D007150:Immunohistochemistry / Q000379:methods; D008565:Membrane Proteins / Q000172:deficiency; D026901:Membrane Transport Proteins; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D016253:Microscopy, Immunoelectron / Q000379:methods; D019579:Neocortex / Q000473:pathology; D009474:Neurons / Q000378:metabolism / Q000648:ultrastructure; D013572:Synaptic Vesicles / Q000378:metabolism* / Q000648:ultrastructure; D013997:Time Factors; D015032:Zinc / Q000378:metabolism*
D002352:Carrier Proteins; D027682:Cation Transport Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C491177:Slc30a3 protein, mouse; D015032:Zinc