INVOLVEMENT OF MITOCHONDRIAL PERMEABILITY TRANSITION, GLUTATHIONE STATUS, PENTOSE PHOSPHATE PATHWAY AND OXIDATIVE DAMAGE IN THE PROTECTIVE EFFECT OF FASTING ON THE ISCHAEMIC-REPERFUSED RAT HEART
| Autor: | A. Varela, María Gabriela Marina Prendes, Natalia G Pascale, María del Mar Jaitovich, M. E. Torresin, E. A. Savino, Romina Hermann, Marcela S González |
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| Rok vydání: | 2009 |
| Předmět: |
medicine.medical_specialty
Physiology Myocardial Reperfusion Injury Pentose phosphate pathway Biology Mitochondrial Membrane Transport Proteins Mitochondria Heart Permeability Pentose Phosphate Pathway Lipid peroxidation chemistry.chemical_compound Physiology (medical) Internal medicine medicine TBARS Animals Glucose-6-phosphate dehydrogenase Lipolysis Rats Wistar Membrane Potential Mitochondrial Pharmacology Mitochondrial Permeability Transition Pore Catabolism Fasting Glutathione Rats Oxidative Stress Endocrinology chemistry Mitochondrial permeability transition pore Female |
| Zdroj: | Clinical and Experimental Pharmacology and Physiology. 36:637-642 |
| ISSN: | 1440-1681 0305-1870 |
| DOI: | 10.1111/j.1440-1681.2008.05122.x |
| Popis: | SUMMARY 1 Fasting, which increases the catabolism of fatty acids, gives functional protection to the ischaemic–reperfused heart. To obtain further knowledge of this cardioprotective effect, changes in mitochondrial permeability transition (MPT) were measured by the entrapment of 2-deoxy-[3H]-glucose (2-DG). We also assessed whether MPT is associated with changes in glutathione status, the activity of glucose-6-phosphate-dehydrogenase (G6PDH) and tissue oxidative damage, estimated by the measurement of Thiobarbituric acid-reactive substances (TBARS). 2 Spontaneously beating hearts of fed and 24 h fasted rats were Langendorff perfused with Krebs’–Ringer bicarbonate solution (10 mmol/L glucose) and exposed to 25 min global ischaemia, followed by 30 min reperfusion. 3 Ischaemia–reperfusion resulted in a fourfold increase in mitochondrial entrapment of 2-DG in the fed group. This response was 29% lower in the fasted group, but there were no concomitant changes in total retention of 2-DG in the heart. Fasting increased the activity of G6PDH by a factor of 1.4 and caused a 2.8-fold increase in the ratio of reduced glutathione to oxidized glutathione (GSH : GSSG) at the end of the pre-ischaemic period. Ischaemia–reperfusion did not affect G6PDH activity, but reduced the GSH : GSSG ratio in both the fed and fasted groups by 50%. Therefore, the GSH : GSSG ratio remained higher in the fasted group. Fasting also decreased cellular levels of TBARS by approximately 25%. Lipolysis of endogenous triacylglycerol was increased during the pre-ischaemic period in the fasted group. 4 These data suggest that the enhancement of fatty acid catabolism that occurs in fasting activates mechanisms that tend to reduce oxidative damage and limit MPT. |
| Databáze: | OpenAIRE |
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