IQUIMEFA   05518
INSTITUTO QUIMICA Y METABOLISMO DEL FARMACO
Unidad Ejecutora - UE
artículos
Título:
Involvement of mitochondrial permeability transition, glutathione status, pentose phosphate pathway and oxidative damage in the protective effect of fasting in the ischemic-reperfused rat heart.
Autor/es:
MARÍA GABRIELA MARINA PRENDES; MARCELA GONZÁLEZ; MARÍA EMILIA TORRESÍN; ROMINA HERMANN; NATALIA PASCALE; MARÍA DEL MAR JAITOVICH; ENRIQUE SAVINO; ALICIA VARELA
Revista:
CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY
Referencias:
Año: 2009 vol. 36 p. 637 - 642
ISSN:
0305-1870
Resumen:
1. Fasting, which increases the catabolism of fatty acids, gives
functional protection to the ischaemicreperfused 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 KrebsRinger bicarbonate
solution (10 mmol/L glucose) and exposed to 25 min global
ischaemia, followed by 30 min reperfusion.
3. Ischaemiareperfusion 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. Ischaemiareperfusion 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 mec
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 KrebsRinger bicarbonate
solution (10 mmol/L glucose) and exposed to 25 min global
ischaemia, followed by 30 min reperfusion.
3. Ischaemiareperfusion 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. Ischaemiareperfusion 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 mec
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 KrebsRinger bicarbonate
solution (10 mmol/L glucose) and exposed to 25 min global
ischaemia, followed by 30 min reperfusion.
3. Ischaemiareperfusion 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. Ischaemiareperfusion 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 mec