Reduction and restoration of mitochondrial DNA content after focal cerebral ischemia/reperfusion

• Published in: Stroke (1970) Vol. 32; no. 10; pp. 2382 - 2387
• Main Authors: HONG CHEN, HU, Chaur-Jong, HE, Yong Y, YANG, Ding-I, JAN XU, HSU, Chung Y
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 01.10.2001; American Heart Association, Inc
• Subjects: Animals; Biological and medical sciences; Blotting, Southern; Cerebral Cortex - blood supply; Cerebral Cortex - chemistry; Cerebral Cortex - metabolism; Densitometry; Disease Models, Animal; Disease Progression; DNA, Mitochondrial - analysis; DNA, Mitochondrial - metabolism; Ischemic Attack, Transient - metabolism; Male; Medical sciences; Mitochondria - chemistry; Mitochondria - metabolism; Neurology; Polymerase Chain Reaction - methods; Rats; Rats, Long-Evans; Reperfusion; Reproducibility of Results; Vascular diseases and vascular malformations of the nervous system; Chromosomal aberration; Nervous system diseases; Stroke; Cerebral cortex; Pathophysiology; Rat; Rodentia; Middle cerebral artery; Cardiovascular disease; Mitochondrial DNA; Cerebral disorder; Vascular disease; Vertebrata; Mammalia; Reperfusion; Ischemia; Mouse; Animal; Central nervous system disease; Deletion; Abnormal chromosome; Cerebrovascular disease
• ISSN: 0039-2499; 1524-4628
• DOI: 10.1161/hs1001.097099

Oxidative damage of mitochondrial DNA (mtDNA) in the ischemic brain is expected after ischemia/reperfusion injury. A recent study demonstrated limited patterns of mtDNA deletion in the brain after ischemia/reperfusion. We studied the ischemia/reperfusion-induced global changes of mtDNA integrity and its restoration in a rat model of transient focal ischemia in vivo. Changes in mtDNA content in the ischemic brain were assessed with the use of a rat stroke model featuring transient severe ischemia confined to the cerebral cortex of the right middle cerebral artery territory for 30 or 90 minutes. A new long polymerase chain reaction method, using mouse DNA as an internal standard, was applied to measure the relative content of intact rat mtDNA. Southern hybridization following alkaline gel electrophoresis was conducted in a parallel study to confirm long polymerase chain reaction results. A reduction in mtDNA content was found after ischemia for 30 and 90 minutes. The mtDNA was restored to near nonischemic levels 24 hours after 30- but not 90-minute ischemia. These results confirm that ischemia/reperfusion causes mtDNA damages. Restoration of the mtDNA content to nonischemic levels after 30-minute ischemia raises the possibility that mtDNA repair or repletion occurs after brief ischemia.