共查询到5条相似文献,搜索用时 15 毫秒
1.
Effects of myocardial ischemia and reperfusion on mitochondrial function and susceptibility to oxidative stress 总被引:8,自引:0,他引:8
We investigated the effects of ischemia duration on the functional response of mitochondria to reperfusion and its relationship
with changes in mitochondrial susceptibility to oxidative stress. Mitochondria were isolated from hearts perfused by the Langendorff
technique immediately after different periods of global ischemia or reperfusion following such ischemia periods. Rates of
O2 consumption and H2O2 release with complex I- and complex II-linked substrates, lipid peroxidation, overall antioxidant capacity, capacity to remove
H2O2, and susceptibility to oxidative stress were determined. The effects of ischemia on some parameters were time dependent so
that the changes were greater after 45 than after 20 min of ischemia, or were significantly different to the nonischemic control
only after 45 min of ischemia. Thus, succinate-supported state 3 respiration exhibited a significant decrease after 20 min
of ischemia and a greater decrease after 45 min, while pyruvate malate-supported respiration showed a significant decrease
only after 45 min of ischemia, indicating an ischemia-induced early inhibition of complex II and a late inhibition of complex
I. Furthermore, both succinate and pyruvate malate-supported H2O2 release showed significant increases only after 45 min of ischemia. Similarly, whole antioxidant capacity significantly increased
and susceptibility to oxidants significantly decreased after 45 min of ischemia. Such changes were likely due to the accumulation
of reducing equivalents, which are able to remove peroxides and maintain thiols in a reduced state. This condition, which
protects mitochondria against oxidants, increases mitochondrial production of oxyradicals and oxidative damage during reperfusion.
This could explain the smaller functional recovery of the tissue and the further decline of the mitochondrial function after
reperfusion following the longer period of oxygen deprivation.
Received 18 May 2001; received after revision 17 July 2001; accepted 24 July 2001 相似文献
2.
Role of nitric oxide in the functional response to ischemia-reperfusion of heart mitochondria from hyperthyroid rats 总被引:2,自引:0,他引:2
Venditti P De Rosa R Cigliano L Agnisola C Di Meo S 《Cellular and molecular life sciences : CMLS》2004,61(17):2244-2252
We investigated the role of nitric oxide (NO) in the mitochondrial derangement associated with the functional response to ischemia-reperfusion of hyperthyroid rat hearts. Mitochondria were isolated at 3000 g from hearts subjected to ischemia-reperfusion, with or without N-nitro-L-arginine (L-NNA, an NO synthase inhibitor). During reperfusion, hyperthyroid hearts displayed tachycardia and low functional recovery. Their mitochondria exhibited O2 consumption similar to euthyroid controls, while H2O2 production, hydroperoxide, protein-bound carbonyl and nitrotyrosine levels, and susceptibility to swelling were higher. L-NNA blocked the reperfusion tachycardic response and increased inotropic recovery in hyperthyroid hearts. L-NNA decreased mitochondrial H2O2 production and oxidative damage, and increased respiration and tolerance to swelling. Such effects were higher in hyperthyroid preparations. These results confirm the role of mitochondria in ischemia-reperfusion damage, and strongly suggest that NO overproduction is involved in the high mitochondrial dysfunction and the low recovery of hyperthyroid hearts from ischemia-reperfusion. L-NNA also decreased protein content and cytochrome oxidase activity of a mitochondrial fraction isolated at 8000 g. This and previous results suggest that the above fraction contains, together with light mitochondria, damaged mitochondria coming from the heaviest fraction, which has the highest cytochrome oxidase activity and capacity to produce H2O2. Therefore, we propose that the high mitochondrial susceptibility to swelling, favoring mitochondrial population purification from H2O2-overproducing mitochondria, limits hyperthyroid heart oxidative stress.Received 24 March 2004; received after revision 9 June 2004; accepted 5 July 2004 相似文献
3.
K. Mashita K. Tajima S. Kawamura S. Tarui 《Cellular and molecular life sciences : CMLS》1984,40(12):1429-1431
Summary Using indomethacin (Ind), a prostaglandin, synthesis inhibitor, in vivo experiments in rats and in vitro experiments with perifusion systems of rat thyroids and pituitaries were conducted. After 35 days of intragastric infusion of Ind, serum TSH levels were markedly increased, the thyroid was swollen and, as a consequence, T3 and T4 levels were normal. The T3 release from perifused rat thyroids under continuous stimulation with 10 mU/ml TSH was inhibited significantly (p<0.01) by 1.0×10–6 M Ind. On the other hand, the TSH release from perifused rat pituitaries under TRH stimulation was enhanced conspicuously by Ind. It was concluded that Ind decelerated thyroid hormone release from the thyroid and accelerated TSH release from the pituitary in perifusion systems. 相似文献
4.
Cancer cell metabolism is characterized by limited oxidative phosphorylation in order to minimize oxidative stress. We have
previously shown that the flavonoid flavone in HT-29 colon cancer cells increases the uptake of pyruvate or lactate into mitochondria,
which is followed by an increase in O2−.. production that finally leads to apoptosis. Similarly, a supply of palmitoylcarnitine in combination with carnitine induces
apoptosis in HT-29 cells by increasing the mitochondrial respiration rate. Here we show that flavone-induced apoptosis is
increased more than twofold in the presence of palmitoylcarnitine due to increased mitochondrial fatty acid transport and
the subsequent metabolic generation of O2−. in mitochondria is the initiating factor for the execution of apoptosis.
Received 12 August 2005; received after revision 12 October 2005; accepted 14 October 2005 相似文献
5.
Mollica MP Lionetti L Crescenzo R D'Andrea E Ferraro M Liverini G Iossa S 《Cellular and molecular life sciences : CMLS》2006,63(3):358-366
This study was designed to examine energetic behaviour of skeletal muscle subsarcolemmal and intermyofibrillar mitochondrial
populations. The data show that subsarcolemmal mitochondria exhibited a lower degree of coupling and efficiency than intermyofibrillar
ones, and can therefore be considered less efficient at producing ATP. In addition, subsarcolemmal mitochondria showed an
increased sensitivity to palmitate-induced uncoupling, in line with high adenine nucleotide translocator content and decreased
oxidative damage. We then determined the effect of 24 h fasting on energetic characteristics of skeletal muscle mitochondrial
populations. We found that fasting enhanced proton leak and decreased the degree of coupling and efficiency, both in the absence
and in the presence of palmitate only in subsarcolemmal mitochondria. Moreover, this mitochondrial population showed lower
oxidative damage, probably due to a counter-regulatory mechanism mediated by uncoupling protein 3. Subsarcolemmal and intermyofibrillar
mitochondria appear to exhibit different energetic characteristics and can be differently affected by physiological stimuli.
Received 28 September 2005; received after revision 9 November 2005; accepted 28 November 2005 相似文献