|
|
Role of antioxidant enzymes in cardioprotective regimens of cold acclimation
Špínová, Šárka ; Žurmanová, Jitka (advisor) ; Holzerová, Kristýna (referee)
The effect of cold on the organism depends on the degree of cold and its duration. Cold acclimation induces a thermoregulatory response, shivering thermogenesis and subsequently the development of non-shivering thermogenesis associated with the activation of brown adipose tissue. Exposure to mild cold in the form of hardening possesses beneficial effects on the whole organism and recently the cardioprotective effects of mild cold acclimation has been described. Increased antioxidant capacity has been demonstrated in the mechanism of cardioprotection induced by hypoxia. The aim of this thesis was to find out whether the protective effect of mild cold acclimatization (8 ± 1 řC) is associated with a change in the capacity of the antioxidant system. To achieve this goal, the protein levels of the main antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, thioredoxin, thioredoxin reductase, aconitase, heme oxygenase) were determined during acclimation to mild cold, specifically in 1-3-10 days and subsequently after 5 weeks, and after a 2-week recovery. The results showed changes in most of the antioxidant proteins, however the effect on cold-elicited cardioprotection must be further verified. Key words: heart, cold acclimation, superoxide dismutase, catalase, glutathione...
|
|
|
Liver gangliosides in cholestasis induced by bile duct ligation.
Hynková, Barbora ; Entlicher, Gustav (advisor) ; Ledvinová, Jana (referee)
Gangliosides are sialic acid-containing glycosphingolipids located on the cell surface of all animal cell types. They play a role as receptor molecules, share in cell-to-cell interaction and protect the cell against harmful environmental factors by increasing of rigidity of cell surface. This diploma thesis studies an influence of experimental cholestasis on hepatic ganglioside composition. Cholestasis was induced by bile duct ligation in Wistar rats. A significant increase of total lipid bound sialic acid and b-series gangliosides (GD1b, GT1b, event. GD3) was found in cholestatic liver when compared with controls. These results found in obstructive cholestasis correspond with the results Majer et al. Biomed. Chromatogr., 21, 446-450 (2007), described in 17α− ethinylestradiol induced cholestasis, but the increase of b-series gangliosides was milder in our study. As a second point, an effect of modulated heme-oxygenase 1 (HO-1) activity was investigated in cholestatis induced bile duct ligation (HO-1 activator- hemine, HO-1 inhibitor- Sn-mesoporphyrin). An increase of a total lipid sialic acid was found in Sn-mesoporphyrin treated animals, but a decrease of some a- and b- series gangliosides was observed. In group with activated HO-1 total sialic acid increased, but the composition of gangliosides...
|
|
|
Changes in the composition and localization of gangliosides in cholestasis associated with other markers of pathological processes in hepatocytes.
Petr, Tomáš ; Muchová, Lucie (advisor) ; Mičuda, Stanislav (referee) ; Befekadu, Asfaw (referee)
This thesis is focused on the study of glycosphingolipids in the rat liver in different types of cholestasis and the effect of oxidative stress on changes in the composition and localization of gangliosides. First, it was necessary to optimize the immunochemical detection of glycosphingolipids. GM1 ganglioside was selected as a representative of a large glycolipid family. We found that minimum water content in the fixing solution was a key condition for fixation of histological sections. Optimized method of GM1 detection was subsequently used in in vivo experiments. We have demonstrated that estrogen-induced cholestasis characterized by high concentrations of bile acids and increased oxidative stress caused changes in the synthesis and distribution of liver gangliosides. HMOX induction is associated with a reduction in oxidative stress level and accompanied by normalization in GSL content. In experiments with obstructive cholestasis, we found that changes in the distribution and synthesis of gangliosides were not strictly specific to a particular type of cholestasis. We assume that it represents a general mechanism of hepatoprotection. We also confirmed the important role of bilirubin, product of HMOX reaction, in protection of hepatocytes against oxidative damage caused by high concentrations of...
|
|
|
Biological effects of edible algae.
Vaňková, Kateřina
Nutritional factors with antioxidant properties, such as those contained in edible algae or green plants, might be implicated in protection against cancer development. Chlorophyll and other tetrapyrrolic compounds, structurally related to heme and antioxidant bile pigment bilirubin, belong to important candidate molecules, which might be responsible for these effects. Based on our studies demonstrating antiproliferative effects of S. platensis edible alga extract on experimental model of human pancreatic adenocarcinoma we investigated in detail the effect of chlorophyll occurring abundantly in this alga. Since only scarce data exist on the antiproliferative effects of chlorophylls, the aim of our study was to assess these effects. The study was performed on experimental models of human pancreatic and prostate cancer. The inhibitory effects of chlorophylls (chlorophyll a, chlorophyll b, chlorophyllin and pheophytin a) on cell proliferation and cell viability were investigated in in vitro studies. Chlorophylls reduced the mRNA expression as well as activity of hemeoxygenase in tested pancreatic cancer cells. Simultaneously, chlorophylls played an important role in redox environment of studied cancer cell lines including modulation of mitochondrial membrane potential, reactive oxygen species (ROS)...
|
|
|
Changes in the composition and localization of gangliosides in cholestasis associated with other markers of pathological processes in hepatocytes.
Petr, Tomáš
This thesis is focused on the study of glycosphingolipids in the rat liver in different types of cholestasis and the effect of oxidative stress on changes in the composition and localization of gangliosides. First, it was necessary to optimize the immunochemical detection of glycosphingolipids. GM1 ganglioside was selected as a representative of a large glycolipid family. We found that minimum water content in the fixing solution was a key condition for fixation of histological sections. Optimized method of GM1 detection was subsequently used in in vivo experiments. We have demonstrated that estrogen-induced cholestasis characterized by high concentrations of bile acids and increased oxidative stress caused changes in the synthesis and distribution of liver gangliosides. HMOX induction is associated with a reduction in oxidative stress level and accompanied by normalization in GSL content. In experiments with obstructive cholestasis, we found that changes in the distribution and synthesis of gangliosides were not strictly specific to a particular type of cholestasis. We assume that it represents a general mechanism of hepatoprotection. We also confirmed the important role of bilirubin, product of HMOX reaction, in protection of hepatocytes against oxidative damage caused by high concentrations of...
|
|
|
Induction of heme oxygenase and biological role of its metabolic products.
Šuk, Jakub ; Muchová, Lucie (advisor) ; Jirsa, Milan (referee) ; Neužil, Jiří (referee)
Heme oxygenase (HMOX) catalyzes first and rate-limiting step in heme degradation. By its action, carbon monoxide (CO), ferrous iron and biliverdin which is subsequently reduced to bilirubin are produced. Before discovery of HMOX reaction mechanism, CO was considered only a toxic waste product without any significant importance for human organism. Bilirubin, marker of liver dysfunction, has been also exposed to similar perception. But results from past decades show that HMOX and its metabolic products play an important role in number of physiological as well as defense against pathophysiological processes. The aim of this thesis was to clarify the role of HMOX and its metabolic products, presumably CO and bilirubin, in vivo and in vitro. We focused on the role of CO in a rat model of lipopolysaccharide-induced cholestasis. We were first to describe tissue distribution and pharmacokinetics of inhaled CO in this animal model and found out that CO inhalation is associated with anti-inflammatory and hepatoprotective effects. In a rat model of ethinylestradiol-induced cholestasis, we demonstrated the anticholestatic effect of HMOX. The induction of HMOX by its substrate heme increased the expression of liver transporters thereby increasing bile flow and simultaneously facilitated effective clearance of...
|
|
|
The role of lipids in the pathogenesis of liver diseases.
Šmíd, Václav ; Muchová, Lucie (advisor) ; Rumlová, Michaela (referee) ; Mičuda, Stanislav (referee)
1 Abstract In this thesis I have focused on the role of lipids in the pathogenesis of liver diseases, specifically on cholestasis and non-alcoholic fatty liver disease (NAFLD). The first major aim was to clarify the changes in liver ganglioside metabolism in various types of cholestasis and to elucidate the role of heme oxygenase-1 (HMOX1) and associated oxidative stress. The second objective was to determine the effects of n-3 polyunsaturated fatty acids (n-3 PUFA) administration on NAFLD development in a rodent dietary model of NAFLD and in patients with metabolic syndrome and NAFLD. Our results suggest that increased ganglioside biosynthesis and their re-distribution might represent a general protective mechanism of hepatocytes under cholestatic conditions (both estrogen-induced and obstructive aetiology). These changes are closely related to oxidative stress and might protect hepatocytes against deleterious effect of accumulated bile acids. The lack of HMOX1 activity and subsequent oxidative stress potentiate pathological changes in the liver and resulted in tissue-specific modulation of synthesis and re-distribution of gangliosides (in vivo and in vitro). Contrary to it, HMOX1 activation has an opposite effect and may represent a general hepatoprotective mechanism. We have proven that observed changes...
|
|
|
Biological effects of edible algae.
Vaňková, Kateřina
Nutritional factors with antioxidant properties, such as those contained in edible algae or green plants, might be implicated in protection against cancer development. Chlorophyll and other tetrapyrrolic compounds, structurally related to heme and antioxidant bile pigment bilirubin, belong to important candidate molecules, which might be responsible for these effects. Based on our studies demonstrating antiproliferative effects of S. platensis edible alga extract on experimental model of human pancreatic adenocarcinoma we investigated in detail the effect of chlorophyll occurring abundantly in this alga. Since only scarce data exist on the antiproliferative effects of chlorophylls, the aim of our study was to assess these effects. The study was performed on experimental models of human pancreatic and prostate cancer. The inhibitory effects of chlorophylls (chlorophyll a, chlorophyll b, chlorophyllin and pheophytin a) on cell proliferation and cell viability were investigated in in vitro studies. Chlorophylls reduced the mRNA expression as well as activity of hemeoxygenase in tested pancreatic cancer cells. Simultaneously, chlorophylls played an important role in redox environment of studied cancer cell lines including modulation of mitochondrial membrane potential, reactive oxygen species (ROS)...
|
|
|
Changes in the composition and localization of gangliosides in cholestasis associated with other markers of pathological processes in hepatocytes.
Petr, Tomáš
This thesis is focused on the study of glycosphingolipids in the rat liver in different types of cholestasis and the effect of oxidative stress on changes in the composition and localization of gangliosides. First, it was necessary to optimize the immunochemical detection of glycosphingolipids. GM1 ganglioside was selected as a representative of a large glycolipid family. We found that minimum water content in the fixing solution was a key condition for fixation of histological sections. Optimized method of GM1 detection was subsequently used in in vivo experiments. We have demonstrated that estrogen-induced cholestasis characterized by high concentrations of bile acids and increased oxidative stress caused changes in the synthesis and distribution of liver gangliosides. HMOX induction is associated with a reduction in oxidative stress level and accompanied by normalization in GSL content. In experiments with obstructive cholestasis, we found that changes in the distribution and synthesis of gangliosides were not strictly specific to a particular type of cholestasis. We assume that it represents a general mechanism of hepatoprotection. We also confirmed the important role of bilirubin, product of HMOX reaction, in protection of hepatocytes against oxidative damage caused by high concentrations of...
|
|
|
Biological effects of edible algae.
Vaňková, Kateřina ; Vítek, Libor (advisor) ; Brůha, Radan (referee) ; Mičuda, Stanislav (referee)
Nutritional factors with antioxidant properties, such as those contained in edible algae or green plants, might be implicated in protection against cancer development. Chlorophyll and other tetrapyrrolic compounds, structurally related to heme and antioxidant bile pigment bilirubin, belong to important candidate molecules, which might be responsible for these effects. Based on our studies demonstrating antiproliferative effects of S. platensis edible alga extract on experimental model of human pancreatic adenocarcinoma we investigated in detail the effect of chlorophyll occurring abundantly in this alga. Since only scarce data exist on the antiproliferative effects of chlorophylls, the aim of our study was to assess these effects. The study was performed on experimental models of human pancreatic and prostate cancer. The inhibitory effects of chlorophylls (chlorophyll a, chlorophyll b, chlorophyllin and pheophytin a) on cell proliferation and cell viability were investigated in in vitro studies. Chlorophylls reduced the mRNA expression as well as activity of hemeoxygenase in tested pancreatic cancer cells. Simultaneously, chlorophylls played an important role in redox environment of studied cancer cell lines including modulation of mitochondrial membrane potential, reactive oxygen species (ROS)...
|
guest ::
