http://www.nature.com/jcbfm/journal/v26/n9/full/9600348a.html
- 1Department of Neurosurgery, Stanford University, Stanford, California, USA
- 2Department of Stanford Stroke Center, Stanford University, Stanford, California, USA
- 3Department of Biological Sciences, Stanford University, Stanford, California, USA
Correspondence:
Dr H Zhao, Department of Neurosurgery, Stanford University School of
Medicine, 1201 Welch Rd, Rm P306, MSLS Bld, Stanford, California
94305-5327, USA. E-mail: hzhao@stanford.edu
Received 24 March 2006; Revised 25 April 2006; Accepted 3 May 2006; Published online 31 May 2006.
Abstract
Cerebral
ischemic preconditioning protects against stroke, but is clinically
feasible only when the occurrence of stroke is predictable. Reperfusion
plays a critical role in cerebral injury after stroke; we tested the
hypothesis that interrupting reperfusion lessens ischemic injury. We
found for the first time that such postconditioning with a series of
mechanical interruptions of reperfusion significantly reduces ischemic
damage. Focal ischemia was generated by permanent distal middle cerebral
artery (MCA) occlusion plus transient bilateral common carotid artery
(CCA) occlusion. After 30 secs of CCA reperfusion, ischemic
postconditioning was performed by occluding CCAs for 10 secs, and then
allowing for another two cycles of 30 secs of reperfusion and 10 secs of
CCA occlusion. Infarct size was measured 2 days later. Cerebral blood
flow (CBF) was measured in animals subjected to permanent MCA occlusion
plus 15 mins of bilateral CCA occlusion, which demonstrates that
postconditioning disturbed the early hyperemia immediately after
reperfusion. Postconditioning dose dependently reduced infarct size in
animals subjected to permanent MCA occlusion combined with 15, 30, and
60 mins of bilateral CCA occlusion, by reducing infarct size
approximately 80%, 51%, and 17%, respectively. In addition,
postconditioning blocked terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end labeling-positive staining, a marker of apoptosis, in the penumbra 2 days after stroke. Furthermore, in situ
superoxide detection using hydroethidine suggested that
postconditioning attenuated superoxide products during early reperfusion
after stroke. In conclusion, postconditioning reduced infarct size,
most plausibly by blocking apoptosis and free radical generation. With
further study it may eventually be clinically applicable for stroke
treatment.
No comments:
Post a Comment