Linked Life Data

16399872

Source:http://linkedlifedata.com/resource/pubmed/id/16399872

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2006-4-10
pubmed:abstractText
We investigated the role of pH, reactive oxygen species (ROS), Ca2+, and the mitochondrial permeability transition (MPT) in pH-dependent ischemia-reperfusion injury to adult rat myocytes. Myocytes were incubated in anoxic Krebs-Ringer-HEPES buffer at pH 6.2 for 3 h to simulate ischemia. To simulate reperfusion, myocytes were reoxygenated at pH 6.2 or 7.4 for 2 h. Some myocytes were treated with MPT blockers (cyclosporin A and N-methyl-4-isoleucine cyclosporin) and antioxidants (desferal, diphenylphenylene diamine, and 2-mercaptopropionyl glycine). Mitochondrial membrane potential, inner membrane permeabilization, and ROS formation were imaged with tetramethylrhodamine methyl ester, calcein, and chloromethyldichlorofluorescein diacetate, respectively. For Ca2+ imaging, myocytes were coloaded with rhod-2 and fluo-4 to evaluate mitochondrial and cytosolic Ca2+, respectively. After 10 min of reperfusion at pH 7.4, calcein redistributed across the mitochondrial inner membrane, an event preceded by mitochondrial ROS formation and accompanied by hypercontracture, mitochondrial depolarization, and then cell death. Acidotic reperfusion, antioxidants, and MPT blockers each prevented the MPT, depolarization, hypercontraction, and cell killing. Antioxidants, but neither MPT blockers nor acidotic reperfusion, inhibited ROS formation after reperfusion. Furthermore, anoxic reperfusion at pH 7.4 prevented cell death. Both mitochondrial and cytosolic Ca2+ increased during ischemia but recovered in the first minutes of reperfusion. Mitochondrial and cytosolic Ca2+ overloading again occurred late after reperfusion. This late Ca2+ overloading was blocked by MPT inhibition. Intramitochondrial Ca2+ chelation by cold loading/warm incubation of BAPTA did not prevent cell death after reperfusion. In conclusion, mitochondrial ROS, together with normalization of pH, promote MPT onset and subsequent myocyte death after reperfusion. In contrast, Ca2+ overloading appears to be the consequence of bioenergetic failure after the MPT and is not a factor promoting MPT onset.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0363-6135
pubmed:author
pubmed:issnType
Print
pubmed:volume
290
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
H2024-34
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Reactive oxygen species, but not Ca2+ overloading, trigger pH- and mitochondrial permeability transition-dependent death of adult rat myocytes after ischemia-reperfusion.
pubmed:affiliation
Department of Cell and Developmental Biology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7090, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural