Autophagy after experimental intracerebral hemorrhage

J Cereb Blood Flow Metab. 2008 May;28(5):897-905. doi: 10.1038/sj.jcbfm.9600578. Epub 2007 Nov 7.

Abstract

Autophagy contributes to ischemic brain injury, but it is not clear if autophagy occurs after intracerebral hemorrhage (ICH). This study examined whether ICH-induced cell death is partly autophagic. It then examined the role of iron in inducing this form of cell death after ICH. Male, adult Sprague-Dawley rats received an infusion of autologous whole blood or ferrous iron into the right basal ganglia. Control rats (sham) had a needle insertion. The rats were killed at 1, 3, 7, or 28 days later. Some rats were treated with either deferoxamine or vehicle after ICH. Microtubule-associated protein light chain-3 (LC3), a biomarker of autophagosome, and cathepsin D, a lysosomal biomarker, were measured by Western blot analysis and immunohistochemistry. Immunofluorescent double-labeling was used to identify the cell types expressing cathepsin D. Electron microscopy was performed to examine the cellular ultrastructure changes after ICH. We found that conversion of LC3-I to LC3-II, cathepsin D expression, and vacuole formation are increased in the ipsilateral basal ganglia after ICH. Intracerebral infusion of iron also resulted in enhanced conversion of LC3-I to LC3-II and increased cathepsin D levels. Deferoxamine (an iron chelator) treatment significantly reduced the conversion of LC3-I to LC3-II and cathepsin D levels after ICH. Our results demonstrated that autophagy occurs after ICH, and iron has a key role in ICH-induced autophagy. This also suggests that iron-induced autophagy may play a role in brain injury in other diseases associated with iron overload.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy / drug effects
  • Autophagy / physiology*
  • Basal Ganglia / metabolism*
  • Basal Ganglia / pathology*
  • Blotting, Western
  • Cathepsin D / metabolism
  • Cerebral Hemorrhage / metabolism*
  • Cerebral Hemorrhage / pathology*
  • Deferoxamine / toxicity
  • Ferrous Compounds / toxicity
  • Iron / toxicity
  • Male
  • Microscopy, Electron
  • Microtubule-Associated Proteins / metabolism
  • Oxidative Stress / drug effects
  • Oxidative Stress / physiology
  • Rats
  • Rats, Sprague-Dawley
  • Siderophores / toxicity
  • Ultrasonography
  • Vacuoles / diagnostic imaging
  • Vacuoles / metabolism
  • Vacuoles / pathology

Substances

  • Ferrous Compounds
  • LC3 protein, rat
  • Microtubule-Associated Proteins
  • Siderophores
  • Iron
  • Cathepsin D
  • Deferoxamine