AIM: The aim of our study was to assess whether simple steatosis impairs liver regeneration after partial hepatectomy (PHx) in rats. METHODS: Male Sprague-Dawley rats were fed a standard diet (ST-1, 10% kcal fat) and high-fat diet (HFD, 71% kcal fat) for 6 weeks. Then the rats were submitted to 2/3 PHx and animals were sacrificed 24, 48 or 72 h after PHx. Serum biochemistry, respiration of mitochondria in liver homogenate, hepatic oxidative stress markers, selected cytokines and DNA content were measured, and histopathological samples were prepared. Liver regeneration was evaluated by incorporation of bromodeoxyuridine (BrdU) to hepatocyte DNA. RESULTS: HFD induced simple microvesicular liver steatosis. PHx caused elevation of serum markers of liver injury in both groups; however, an increase in these parameters was delayed in HFD group. Hepatic content of reduced glutathione was significantly increased in both groups after PHx. There were no significant changes in activities of respiratory complexes I and II (state 3). Relative and absolute liver weights, total DNA content, and DNA synthesis exerted very similar changes in both ST-1 and HFD groups after PHx. CONCLUSION: PHx-induced regeneration of the rat liver with simple steatosis was not significantly affected when compared to the lean liver.
- MeSH
- hepatektomie * MeSH
- jaterní mitochondrie patologie fyziologie MeSH
- jaterní testy MeSH
- játra patologie patofyziologie MeSH
- krysa rodu rattus MeSH
- potkani Sprague-Dawley MeSH
- regenerace jater fyziologie MeSH
- ztučnělá játra patologie patofyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Fatty liver disease associated with obesity is an important medical problem and the mechanisms for lipid accumulation in hepatocytes are not fully elucidated yet. Recent findings indicate that mitochondria play an important role in this process. Our data on hepatocytes in which mitochondria are in contact with other cytosolic structures important for their function, extend observations obtained on isolated mitochondria and confirm inhibition of Complex I activity in hepatocytes isolated from rats fed by high fat diet (HFD) compared with controls fed by standard diet (STD). Furthermore we have found that HFD-hepatocytes are more sensitive to the peroxidative stress because under these conditions also Complex II activity is disturbed. Therefore in HFD animals decrease of Complex I activity cannot be compensated by Complex II substrates as in STD hepatocytes. Our data thus indicates that combination of HFD and peroxidative stress potentiates HFD damaging effect of mitochondria because both branches of the respiratory chain (NADH- and flavoprotein-dependent) are disturbed.
- MeSH
- dieta s vysokým obsahem tuků škodlivé účinky MeSH
- hepatocyty fyziologie MeSH
- jaterní mitochondrie fyziologie MeSH
- krysa rodu rattus MeSH
- oxidační stres fyziologie MeSH
- potkani Wistar MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Mitochondrial production of reactive oxygen species (ROS) due to up-regulated glucose oxidation is thought to play a crucial, unifying role in the pathogenesis of chronic complications associated with diabetes mellitus. Mitochondrial permeability transition (MPT) is an interesting phenomenon involved in calcium signalling and cell death. We investigated the effects of glucose and several of its metabolites on calcium-induced MPT (measured as mitochondrial swelling) in isolated rat liver mitochondria. The presence of glucose, glucose 1-phosphate (both at 30 mM) or methylglyoxal (6 mM) significantly slowed calcium-induced mitochondrial swelling. Thirty mM glucose also resulted in a significant delay of MPT onset. In contrast, 30 mM fructose 6-phosphate accelerated swelling, whereas glucose 6-phosphate did not influence the MPT. The calcium binding potentials of the three hexose phosphates were tested and found similar. In vitro hydrogen peroxide production by mitochondria respiring on succinate in the presence of rotenone was independent of mitochondrial membrane potential and increased transiently during calcium-induced MPT. Inhibition of MPT with cyclosporine A resulted in decreased mitochondrial ROS production in response to calcium. In contrast, inhibition of MPT by methylglyoxal was accompanied by increased ROS production in response to calcium. In conclusion, we confirm that methylglyoxal is a potent inhibitor of MPT. In addition, high levels of glucose, glucose 1-phosphate and fructose 6-phosphate can also affect MPT. Methylglyoxal simultaneously inhibits MPT and increases mitochondrial ROS production in response to calcium. Our findings provide a novel context for the role of MPT in glucose sensing and the cellular toxicity caused by methylglyoxal.
- MeSH
- glukosa farmakologie metabolismus MeSH
- glukosafosfáty farmakologie metabolismus MeSH
- intracelulární membrány fyziologie účinky léků MeSH
- jaterní mitochondrie fyziologie účinky léků ultrastruktura MeSH
- krysa rodu rattus MeSH
- permeabilita účinky léků MeSH
- potkani Wistar MeSH
- pyruvaldehyd farmakologie MeSH
- reaktivní formy kyslíku metabolismus MeSH
- vápník farmakologie metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
- MeSH
- financování organizované MeSH
- jaterní mitochondrie fyziologie metabolismus MeSH
- membránové potenciály MeSH
- mikroelektrody využití MeSH
- oniové sloučeniny MeSH
- organofosforové sloučeniny MeSH
- oxidativní fosforylace MeSH
- potkani Wistar MeSH
- spotřeba kyslíku fyziologie MeSH
- sukcinátdehydrogenasa chemie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- abstrakty MeSH
The aim of the study was to evaluate time course and dose dependence of peroxidative damage induced by tert-butyl hydroperoxide (tBHP) in rat hepatocytes cultured in suspension and in monolayer. At the lowest (0.1 mM) concentration, decrease of cytosolic glutathione and discharge of mitochondrial membrane potential (MMP) could be detected. Significant increases in leakage of lactate dehydrogenase and in malondialdehyde concentrations together with decrease of pyruvate-dependent respiration were detected at higher tBHP concentrations (above 0.5 mM) and after longer periods of incubation. Changes in plasma membrane integrity were observed at 1 mM concentration of tBHP. Succinate-dependent oxidation was most resistant to peroxidative damages. Opening of the mitochondrial permeability transition pore was responsible for the discharge of mitochondria membrane potential. In the presence of cyclosporine A and succinate, the membrane potential could be restored. Our data showed that the most sensitive indicators of the peroxidative damage are changes of cytosolic glutathione concentration and MMP.
- MeSH
- cytosol metabolismus účinky léků MeSH
- financování organizované MeSH
- glutathion metabolismus MeSH
- hepatocyty metabolismus účinky léků MeSH
- jaterní mitochondrie enzymologie fyziologie účinky záření MeSH
- krysa rodu rattus MeSH
- kultivované buňky MeSH
- L-laktátdehydrogenasa metabolismus MeSH
- malondialdehyd metabolismus MeSH
- membránový potenciál mitochondrií účinky léků MeSH
- oxidační stres účinky léků fyziologie MeSH
- oxidancia toxicita MeSH
- peroxidace lipidů účinky léků MeSH
- potkani Wistar MeSH
- spotřeba kyslíku účinky léků MeSH
- terc-butylhydroperoxid toxicita MeSH
- viabilita buněk účinky léků MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- MeSH
- herbicidy metabolismus toxicita MeSH
- jaterní mitochondrie fyziologie účinky léků MeSH
- lipidy krev MeSH
- myši MeSH
- oxidativní fosforylace fyziologie účinky léků MeSH
- simazin metabolismus toxicita MeSH
- ztučnělá játra chemicky indukované krev patofyziologie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- srovnávací studie MeSH
