Selective replacement of mitochondrial DNA increases the cardioprotective effect of chronic continuous hypoxia in spontaneously hypertensive rats

0474681 - FGÚ 2018 RIV GB eng J - Journal Article
Neckář, Jan - Svatoňová, Anna - Weissová, Romana - Drahota, Zdeněk - Zajíčková, Pavlína - Brabcová, I. - Kolář, D. - Alánová, Petra - Vašinová, Jana - Šilhavý, Jan - Hlaváčková, Markéta - Tauchmannová, Kateřina - Milerová, Marie - Ošťádal, Bohuslav - Červenka, L. - Žurmanová, J. - Kalous, M. - Nováková, Olga - Novotný, J. - Pravenec, Michal - Kolář, František
Selective replacement of mitochondrial DNA increases the cardioprotective effect of chronic continuous hypoxia in spontaneously hypertensive rats.
Clinical science. Roč. 131, č. 9 (2017), s. 865-881. ISSN 0143-5221. E-ISSN 1470-8736
R&D Projects: GA ČR(CZ) GA13-10267S; GA ČR(CZ) GB14-36804G; GA MŠMT(CZ) LL1204
Institutional support: RVO:67985823
Keywords : chronic hypoxia * heart * hypertension * ischaemia–reperfusion injury * mitochondrial genome * mitochondrial permeability transition pore
OECD category: Physiology (including cytology)
Impact factor: 5.220, year: 2017

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 68±3.0% and 65±5% of the area at risk in normoxic SHR and SHR-mtBN strains, respectively. CNH significantly decreased myocardial infarction to 46±3% in SHR. In hypoxic SHR-mtBN strain, IS reached 33±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.
Permanent Link: http://hdl.handle.net/11104/0271673