Effect of estrogen on mitochondrial function and intracellular stress markers in rat liver and kidney following trauma-hemorrhagic shock and prolonged hypotension.
Trauma-hemorrhage (T-H) is known to impair tissue perfusion, leading to tissue hypoxia, and thus affecting mitochondria, the organelles with the highest oxygen demand. In a model of T-H and prolonged hypotension without fluid resuscitation, administration of a small volume of 17beta-estradiol (E2), but not vehicle, prolonged the survival of rats for 3 h, even in the absence of fluid resuscitation. The main finding of this study is that T-H followed by prolonged hypotension significantly affects mitochondrial function, endoplasmic reticulum (ER) stress markers and free iron levels, and that E2 ameliorated all these changes. All of these changes were observed in the liver but not in the kidney. The sensitivity of mitochondrial respiration to exogenous cytochrome c can reflect increased permeability of the outer mitochondrial membrane for cytochrome c. Increased levels of free iron are indicative of oxidative stress, but neither oxidative nor nitrosylative stress markers changed. The spliced isoform of XBP1 mRNA (an early marker of ER stress) and the expression of C/EBP homologous protein (CHOP) (a protein regulating ER stress-induced apoptosis) were elevated in T-H animals but remained unchanged if T-H rats received E2. Both the prevention of elevated sensitivity of mitochondrial respiration to cytochrome c and a decrease in ER stress by E2 maintain functional integrity of the liver and may help the organ during prolonged hypotension and following resuscitation. A decrease in free iron levels by E2 is more relevant for resuscitation, often accompanied by oxidative stress reaction. Thus, E2 appears to be a novel hormonal adjunct that prolongs permissive hypotension during lengthy transportation of the injured patient between the injury site and the hospital in both civilian and military injuries.
Kozlov
Andrey V
AV
Ludwig Boltzmann Institute for Experimental and Clinical Traumatology in the AUVA, Vienna, Austria.
Duvigneau
J Catharina
JC
Hyatt
Tanya C
TC
Raju
Raghavan
R
Behling
Tricia
T
Hartl
Romana T
RT
Staniek
Katrin
K
Miller
Ingrid
I
Gregor
Wolfgang
W
Redl
Heinz
H
Chaudry
Irshad H
IH
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects*; D018698:Glutamic Acid / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006470:Hemorrhage / Q000378:metabolism*; D007022:Hypotension / Q000139:chemically induced / Q000378:metabolism*; D007249:Inflammation / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008293:Malates / Q000378:metabolism; D008297:Male; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D050050:Protein Carbonylation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D000071701:Regulatory Factor X Transcription Factors; D012119:Respiration / Q000187:drug effects; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D000071717:X-Box Binding Protein 1; D000091342:Endoplasmic Reticulum Chaperone BiP
D015415:Biomarkers; D004268:DNA-Binding Proteins; D004958:Estradiol; D018698:Glutamic Acid; D006360:Heat-Shock Proteins; D007501:Iron; D008293:Malates; D000071701:Regulatory Factor X Transcription Factors; D017392:Thiobarbituric Acid Reactive Substances; D014157:Transcription Factors; D000071717:X-Box Binding Protein 1; C051684:GRP78 protein, rat; D000091342:Endoplasmic Reticulum Chaperone BiP; C000605545:Xbp1 protein, rat; C030298:malic acid