Endurance training limits the functional alterations of rat heart mitochondria submitted to in vitro anoxia-reoxygenation.
BACKGROUND
Studies analysing the effect of endurance training on heart mitochondrial function submitted to in vitro anoxia-reoxygenation (A-R) are missing. The present study aimed to investigate the effect of moderate endurance treadmill training (14 weeks) against rat heart mitochondrial dysfunction induced by in vitro A-R.


METHODS
Respiratory parameters (state 3, state 4, ADP/O and respiratory control ratio-RCR) and oxidative damage markers (carbonyl groups and malondialdehyde) were determined in isolated mitochondria before and after 1 min anoxia followed by 4 min reoxygenation. Levels of heat shock protein 60 kDa (HSP60) and 70 kDa (HSP70) were measured before A-R in mitochondria and whole muscle homogenate, respectively.


RESULTS
A-R significantly impaired the rate of state 3 and state 4 respiration, as well as the RCR and ADP/O in the sedentary group. However, mitochondrial state 3 respiration was significantly higher in trained than in the sedentary group both before and after A-R. The impairments in RCR, ADP/O ratio and state 4 induced by A-R in sedentary group were significantly attenuated in endurance-trained group. The inhibition of state 4 induced by GDP was significantly higher in trained than in sedentary group. Oxidative modifications of mitochondrial proteins and phospholipids were found in sedentary group after A-R, although limited in trained group. Increased levels of mitochondrial HSP60 and tissue HSP70 accompanied the lower decrease in the respiratory function after A-R observed in trained group.


CONCLUSIONS
We therefore concluded that endurance training limited the impairments on rat heart mitochondria caused by the oxidant insult inflicted by in vitro A-R.
Ascensão
António
A
Department of Sport Biology, Faculty of Sport Sciences, University of Porto, Portugal. aascensao@fcdef.up.pt
Magalhães
José
J
Soares
José M C
JM
Ferreira
Rita
R
Neuparth
Maria J
MJ
Marques
Franklim
F
Oliveira
Paulo J
PJ
Duarte
José A
JA
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D019069:Cell Respiration; D018834:Chaperonin 60 / Q000378:metabolism; D002950:Citrate (si)-Synthase / Q000378:metabolism; D004195:Disease Models, Animal; D005080:Exercise Test; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D000860:Hypoxia / Q000378:metabolism / Q000503:physiopathology*; D015227:Lipid Peroxidation; D008297:Male; D008929:Mitochondria, Heart / Q000378:metabolism*; D010085:Oxidative Phosphorylation; D010101:Oxygen Consumption; D010805:Physical Conditioning, Animal; D010807:Physical Endurance; D050050:Protein Carbonylation; D051381:Rats; D017208:Rats, Wistar
D015415:Biomarkers; D018834:Chaperonin 60; D018840:HSP70 Heat-Shock Proteins; D002950:Citrate (si)-Synthase