(Stroke. 1999;30:2456-2463.)
© 1999 American Heart Association, Inc.
Original Contributions |
Early Decrease of XRCC1, a DNA Base Excision Repair Protein, May Contribute to DNA Fragmentation After Transient Focal Cerebral Ischemia in Mice
From the Departments of Neurosurgery, Neurology and Neurological Sciences, and Program in Neurosciences, Stanford University School of Medicine, Palo Alto, Calif.
Correspondence to Pak H. Chan, PhD, Neurosurgical Laboratories, Stanford University, 701B Welch Rd, #148, Palo Alto, CA 94304. E-mail phchan{at}leland.stanford.edu
Background and Purpose—DNA damage and the DNA repair mechanism are known to be involved in ischemia/reperfusion injury in the brain. The x-ray repair cross-complementing group 1 (XRCC1) protein plays a central role in the DNA base excision repair pathway by interacting with DNA ligase III and DNA polymerase ß. The present study examined the protein expression of XRCC1 and DNA fragmentation before and after transient focal cerebral ischemia (FCI).
Methods—Adult male CD-1 mice were subjected to 60 minutes of FCI by intraluminal blockade of the middle cerebral artery. XRCC1 protein expression was analyzed by immunohistochemistry and Western blot analysis. DNA damage was evaluated by gel electrophoresis and terminal deoxynucleotidyl transferase–mediated uridine 5'-triphosphate-biotin nick end-labeling (TUNEL). The spatial relationship between XRCC1 expression and DNA damage was examined by double staining with XRCC1 and TUNEL after FCI.
Results—Immunohistochemistry showed the nuclear expression of XRCC1 in all regions of the control brains and that it was predominant in the hippocampus. The XRCC1 level was markedly reduced in the caudate putamen at 10 minutes, further decreased in the entire middle cerebral artery territory at 1 hour, and remained reduced until 4 and 24 hours after FCI. Western blot analysis of the normal control brain showed a characteristic band of 70 kDa, which decreased after FCI. A significant amount of DNA fragmentation was detected by DNA gel electrophoresis 24 hours but not 4 hours after FCI. Double staining showed that the neurons that lost XRCC1 immunoreactivity became TUNEL positive.
Conclusions—These results suggest that the early decrease of XRCC1 and the failure of the DNA repair mechanism may contribute, at least in part, to DNA fragmentation after FCI.
Editorial Comment
Guest Editors, Department of Neurology, Washington University School of Medicine, St Louis, Missouri
This article has been cited by other articles:
 |
|
 |
|
  S. Mahabir, C. C Abnet, Y.-L. Qiao, L. D Ratnasinghe, S. M Dawsey, Z.-W. Dong, P. R Taylor, and S. D Mark A prospective study of polymorphisms of DNA repair genes XRCC1, XPD23 and APE/ref-1 and risk of stroke in Linxian, China J Epidemiol Community Health, August 1, 2007; 61(8): 737 - 741. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Y. Song, J. W. Lim, H. Kim, T. Morio, and K. H. Kim Oxidative Stress Induces Nuclear Loss of DNA Repair Proteins Ku70 and Ku80 and Apoptosis in Pancreatic Acinar AR42J Cells J. Biol. Chem., September 19, 2003; 278(38): 36676 - 36687. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Sugawara, N. Noshita, A. Lewen, G. W. Kim, and P. H. Chan Neuronal Expression of the DNA Repair Protein Ku 70 After Ischemic Preconditioning Corresponds to Tolerance to Global Cerebral Ischemia Stroke, October 1, 2001; 32(10): 2388 - 2393. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. W. Kim, N. Noshita, T. Sugawara, and P. H. Chan Early Decrease in DNA Repair Proteins, Ku70 and Ku86, and Subsequent DNA Fragmentation After Transient Focal Cerebral Ischemia in Mice Stroke, June 1, 2001; 32(6): 1401 - 1407. [Abstract] [Full Text] [PDF]
|
|