Neckar 2017 Clin Sci (Lond)
Neckar J, Svatonova A, Weissova R, Drahota Z, Zajickova P, Brabcova I, Kolar D, Alanova P, Vasinova J, Silhavy J, Hlavackova M, Tauchmannova K, Milerova M, Ostadal B, Cervenka L, Zurmanova J, Kalous M, Novakova O, Novotny J, Pravenec M, Kolar F (2017) Selective replacement of mitochondrial DNA increases the cardioprotective effect of chronic continuous hypoxia in spontaneously hypertensive rats. Clin Sci (Lond) 131:865-81. |
Neckar J, Svatonova A, Weissova R, Drahota Z, Zajickova P, Brabcova I, Kolar D, Alanova P, Vasinova J, Silhavy J, Hlavackova M, Tauchmannova K, Milerova M, Ostadal B, Cervenka L, Zurmanova Jitka, Kalous M, Novakova O, Novotny J, Pravenec M, Kolar F (2017) Clin Sci (Lond)
Abstract: Mitochondria play an essential role in improved cardiac ischaemic tolerance conferred by adaptation to chronic hypoxia. In the present study, we analysed the effects of continuous normobaric hypoxia (CNH) on mitochondrial functions, including the sensitivity of the mitochondrial permeability transition pore (MPTP) to opening, and infarct size (IS) in hearts of spontaneously hypertensive rats (SHR) and the conplastic SHR-mtBN strain, characterized by the selective replacement of the mitochondrial genome of SHR with that of the more ischaemia-resistant brown Norway (BN) strain. Rats were adapted to CNH (10% O2, 3 weeks) or kept at room air as normoxic controls. In the left ventricular mitochondria, respiration and cytochrome c oxidase (COX) activity were measured using an Oxygraph-2k and the sensitivity of MPTP opening was assessed spectrophotometrically as Ca2+-induced swelling. Myocardial infarction was analysed in anaesthetized open-chest rats subjected to 20 min of coronary artery occlusion and 3 h of reperfusion. The IS reached 68Β±3.0% and 65Β±5% of the area at risk in normoxic SHR and SHR-mtBN strains, respectively. CNH significantly decreased myocardial infarction to 46Β±3% in SHR. In hypoxic SHR-mtBN strain, IS reached 33Β±2% and was significantly smaller compared with hypoxic SHR. Mitochondria isolated from hypoxic hearts of both strains had increased detergent-stimulated COX activity and were less sensitive to MPTP opening. The maximum swelling rate was significantly lower in hypoxic SHR-mtBN strain compared with hypoxic SHR, and positively correlated with myocardial infarction in all experimental groups. In conclusion, the mitochondrial genome of SHR modulates the IS-limiting effect of adaptation to CNH by affecting mitochondrial energetics and MPTP sensitivity to opening.
Β© 2017 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society. β’ Keywords: Chronic hypoxia, Heart, Hypertension, Ischaemiaβreperfusion injury, Mitochondrial genome, Mitochondrial permeability transition pore β’ Bioblast editor: Cecatto C β’ O2k-Network Lab: CZ Prague Houstek J, CZ Prague Kalous M
Labels: MiParea: Respiration, mtDNA;mt-genetics
Pathology: Cardiovascular
Stress:Permeability transition, Hypoxia
Organism: Rat
Tissue;cell: Heart
Preparation: Homogenate, Isolated mitochondria
Enzyme: Complex I, Complex II;succinate dehydrogenase, Complex III, Complex IV;cytochrome c oxidase, TCA cycle and matrix dehydrogenases
Regulation: Calcium
Coupling state: LEAK, OXPHOS
Pathway: N, CIV, NS
HRR: Oxygraph-2k
2020-05