J Korean Neurosurg Soc.  2011 Dec;50(6):481-485. 10.3340/jkns.2011.50.6.481.

Serial Expression of Hypoxia Inducible Factor-1alpha and Neuronal Apoptosis in Hippocampus of Rats with Chronic Ischemic Brain

Affiliations
  • 1Department of Veterinary Pathobiology, Small Animal Tumor Diagnostic Center, College of Veterinary Medicine, Konkuk University, Seoul, Korea.
  • 2Department of Neurosurgery, Konkuk University Medical Center, Seoul, Korea. ctmoon@kuh.ac.kr

Abstract


OBJECTIVE
The purpose of this study is to investigate serial changes of hypoxia-inducible factor 1alpha (HIF-1alpha), as a key regulator of hypoxic ischemia, and apoptosis of hippocampus induced by bilateral carotid arteries occlusion (BCAO) in rats.
METHODS
Adult male Wistar rats were subjected to the permanent BCAO. The time points studied were 1, 2, 4, 8, and 12 weeks after occlusions, with n=6 animals subjected to BCAO, and n=2 to sham operation at each time point, and brains were fixed by intracardiac perfusion fixation with 4% neutral-buffered praraformaldehyde for brain section preparation. Immunohistochemistry (IHC), western blot and terminal uridine deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay were performed to evaluate HIF-1alpha expression and apoptosis.
RESULTS
In IHC and western blot, HIF-1alpha levels were found to reach the peak at the 2nd week in the hippocampus, while apoptotic neurons, in TUNEL assay, were maximal at the 4th week in the hippocampus, especially in the cornu ammonis 1 (CA1) region. HIF-1alpha levels and apoptosis were found to fluctuate during the time course.
CONCLUSION
This study showed that BCAO induces acute ischemic responses for about 4 weeks then chronic ischemia in the hippocampus. These in vivo data are the first to show the temporal sequence of apoptosis and HIF-1alpha expression.

Keyword

Bilateral carotid artery occlusion; Hippocampus; Hypoxic ischemia; Hypoxia-inducible factor 1alpha; Apoptosis

MeSH Terms

Adult
Animals
Anoxia
Apoptosis
Blotting, Western
Brain
Carotid Arteries
DNA Nucleotidylexotransferase
Hippocampus
Humans
Immunohistochemistry
In Situ Nick-End Labeling
Ischemia
Male
Neurons
Perfusion
Rats
Rats, Wistar
Salicylamides
Uridine
DNA Nucleotidylexotransferase
Salicylamides
Uridine
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