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ref: Szarowski-2003.09 tags: Michigan array silicon histology MEA cornell date: 01-28-2013 20:47 gmt revision:6 [5] [4] [3] [2] [1] [0] [head]

PMID-12914963[0] Brain responses to micro-machined silicon devices.

  • Used 2 different implants (rough & sharp corners, smooth), 2 different ways of inserting (slow, by hand).
    • Neither made much diff.
  • Measured GFAP = glial fibrillary acidic protein, a standard measure for assesing reactive gliosis [44,18,28,33,35].
    • Normally larger astrocytes were seen around larger blood vessels.
    • "At four weeks, a clear sheath of GFAP-positive astrocytes was observed"
    • GFAP labeled sheath seems to have plateaued at 6 weeks. (The sheath may be useful for our devices... )
  • Measured Vimentin, which is increased in reactive astrocytes and is not normally expressed in mature astrocytes [6,12,15,40].
    • In control animals vimentin only present in ependymal lining of the ventricles.
    • At 6 weeks, sites around both types of devices had a compact sheath of vimentin-positive astrocytes 50-100um.
    • Seemed to be a plateau as with GFAP .. though it seems to label a slightly distinct set of cells.
  • Also labeled reactive microglia with ED1 [4,19,27,36].
  • Quote: These data indicate that device insertion promotes two responses-an early response that is proportional to device size and a sustained response that is independent of device size, geometry, and surface roughness. The early response may be associated with the amount of damage generated during insertion. The sustained response is more likely due to tissue-device interactions.

____References____

[0] Szarowski DH, Andersen MD, Retterer S, Spence AJ, Isaacson M, Craighead HG, Turner JN, Shain W, Brain responses to micro-machined silicon devices.Brain Res 983:1-2, 23-35 (2003 Sep 5)