The circadian rhythms of many behavioral and physiological functions are regulated by the major circadian pacemaker in the suprachiasmatic nucleus. Long-term opiate addiction and drug withdrawal may affect circad ian rhythmicity of various hormones or the sleep/activity pattern of many experimental subjects; however, limited research has been done on the long -term effects of sustained opiate administration on the intrinsic rhythmicity in the suprachiasmatic nucleus and pineal gland. Here we compared the effects of repeated daily treatment of rats with morphine or methadone and subsequent naloxone-precipitated withdrawal on the expression of the Per1, Per2, and Avp mRNAs in the suprachiasmatic nucleus and on arylalky lamine N-acetyltransferase activity in the pineal gland. We revealed that 10-day administration and withdrawal of both these drugs failed to affect clock genes and Avp expression in the SCN. Our results indicate that opioid-induced changes in behavioral a nd physiological rhythms originate in brain structures downstream of the suprachiasmatic nucleus regulatory output pathway. Furthermore, we observed that acute withdrawal from methadone markedly extended the period of high night AA -NAT activity in the pine al gland. This suggests that withdrawal from methadone, a widely used drug for the treatment of opioid dependence, may have stronger impact on melatonin synthesis than withdrawal from morphine., D. Pačesová, J. Novotný, Z. Bendová., and Obsahuje bibliografii
Factors modulating cardiac susceptibility to ischemia-reperfusion (I/R) are permannetly attracting the attention of experimental cardiology research. We investigated, whether continuous 24 h/day light exposure of rats can modify cardiac response to I/R, NO-synthase (NOS) activity and the level of oxidative load represented by conjugated dienes (CD) concentration. Two groups of male adult Wistar rats were studied: controls exposed to normal light/dark cycle (12 h/day light, 12 h/day dark) and rats exposed to continuous light for 4 weeks. Perfused isolated hearts (Langendorff technique) were exposed to 25 min global ischemia and subsequent 30 min reperfusion. The recovery of functional parameters (coronary flow, left ventricular developed pressure, contractility and relaxation index) during reperfusion as well as the incidence, severity and duration of arrhythmias during first 10 min of reperfusion were determined. The hearts from rats exposed to continuous light showed more rapid recovery of functional parameters but higher incidence, duration and severity of reperfusion arrhythmias compared to controls. In the left ventricle, the NOS activity was attenuated, but the CD concentration was not significantly changed. We conclude that the exposure of rats to continuous light modified cardiac response to I/R. This effect could be at least partially mediated by attenuated NO production., R. Važan, P. Janega, S. Hojná, J. Zicha, F. Šimko, O. Pecháňová, J. Styk, L'. Paulis., and Obsahuje bibliografii
The aim of our work was to compare the effect of D-galactosamine (GalN) on primary cultures of lean and steatotic rat hepatocytes isolated from intact and fatty liver, respectively. GalN caused more severe injury to steatotic hepatocytes than to lean cells as documented by lactate dehydrogenase leakage. Necrotic mode of cell death strongly prevails over apoptosis since we did not observe any significant increase in activities of caspase 3, 8 and 9 in any group of hepatocytes treated with GalN. Reactive oxygen species (ROS) formation and lipid peroxidation were elevated in a dose-dependent manner by GalN and were significantly more pronounced in fatty hepatocytes. A decrease in the percentage of hepatocytes with energized mitochondria was observed from 30 mM and 10 mM GalN in lean and steatotic hepatocytes, respectively. Our results undoubtedly indicate that steatotic hepatocytes exert higher sensitivity to the toxic effect of GalN. This sensitivity may be caused by more intensive GalN-induced ROS production and lipid peroxidation and by higher susceptibility of mitochondria to loss of mitochondrial membrane potential in steatotic hepatocytes. In our experimental arrangement, apoptosis does not seem to participate considerably on hepatotoxic action of GalN in either group of hepatocytes., O. Kučera, H. Lotková, O. Sobotka Z. Červinková., and Obsahuje bibliografii
a1_Renal transplantation is associated with a large number of risk factors that can have an influe nce on early renal graft function (ERGF). One of these factors could be the increasing number of obese kidney donors. The mechanisms of reduced ERGF in obese kidney donors are still poorly understood. To that end, w e compared ERGF in recipients with body mass index (BMI), perivascular fat and plasma inflammation markers of live kidney donors. We hypothesi zed that the BMI of donors would negatively correlate with an average increase of glomerular filtration rate (GFR ) and that it would also be associated wi th increased perivascular and plasma inflammation markers in the first seven days after transplantation. Between January 2013 and December 2014, some 58 living kidney transplantation pairs were included in the study. Donor and recipient demographic data, preoperative BMI, blood C -reactive protein (CRP) and adiponectin levels, perivascular adipose tissue (PAT) samples and recipient blood creatinine levels were analy zed. The median CRP of donors was 0.68 mg/l (max: 8.66 mg/l, min: 0.33 mg/l), the median of M1 macrophages (CD14+CD16+) in one gram of PAT was 5940 (max: 41 100, min: 248) and the median of adiponectin was 411 930 pg/ml (max: 14 217 000, min: 167 300) in plasma. We did not find any association between early renal graft function and the percentage o f M1 macrophages in donor perirenal adipose tissue (p=0.83, r=0.03, n=58), adiponectin (p=0.65, r=0.06, n=58) or CRP (p=0.16, r=0.2, n=58) in plasma. The obesity level of donors, expressed as BMI, did not correlate with early renal graft function in the first seven days after transplantation. The associations between ERGF and plasma and perivascular fat inflammation markers were not significant., a2_We confirmed a negative correlation between the BMI of recipients and an average increase of GFR in the first sev en days after transplantation (p<0.02, r= -0.325, N=58). We confirmed a negative correlation of adiponectin plasma concentration to the BMI of donors., F. Thieme, L. Janousek, J. Fronek, A. Kralova, S. Cejkova, I. Kralova Lesna, R. Poledne., and Obsahuje bibliografii
Increased and prolonged postprandial lipemia has been identified as a risk factor of cardiovascular disease. However, there is no consensus on how to test postprandial lipemia, especia lly with respect to the composition of an experimental meal. To address this question of how glucose, when added to a fat load, affects the selected parameters of postprandial lipemia, we carried out a study in 30 healthy male volunteers. Men consumed an experimental meal containing either 75 g of fat + 25 g of glucose (F+G meal) or 75 g of fat (F meal) in a control experiment. Blood was taken before the meal and at selected time points within the following 8 h. Glucose, when added to a fat load, induced an increase of glycemia and insulinemia and, surprisingly, a 20 % reduction in the response of both total and active glucagon -like peptide -1 (GLP -1) concentration. The addition of glucose did not affect the magnitude of postprandial triglyceridemia and TRL -C and TRL -TG concentrations but stimulated a faster response of chylomicrons to the test meal, evaluated by changes in apolipoprotein B -48 concentrations. The addition of glucose induced the physiological response of insulin and the lower response of GLP -1 to the test meal during the early postprandial phase, but had no effect on changes of TRL -cholesterol and TRL -TG within 8 h after the meal., K. Zemánková, J. Mrázková, J. Piťha, J. Kovář., and Obsahuje bibliografii
Experiments were conducted to study the effect of goldthioglucose (GTG) upon the processes associated with lipid peroxidation. The glucose-6-phosphate dehydrogenase activity (G6PD; E.C.1.1.1.49) in red blood cells (RBC) and the amount of malonaldehyde precursors (MDA) per gram of brain, liver and kidney were determined. Adult mice received i.p. injections for three consecutive days of either saline (controls) or GTG dissolved in saline, in a dose of 0.10 mg.g-1 or 0.15 mg.g-1 b.w. In mice receiving higher dose of GTG the G6PD activity was significantly increased (349.38± 17.46 mU.10-9 RBC compared to 258.2± 14.46 mU.10-9 RBC in control animals). The content of MDA precursors rose significantly from 4.8± 0.81 m mol.g-1 of the liver in controls to 8.12± 1.41 m mol.g -1 and 7.88± 0.51 m mol.g-1 and from 18.71± 1.01 m mol.g-1 of the kidneys in controls to 24.25± 1.25 m mol.g-1 and 24.88± 1.7 m mol.g-1 respectively. The GTG-induced higher levels of MDA precursors and increased G6PD activity in RBC corresponds to the rise in lipid peroxidation and its participation in producing the lesions after experimental and therapeutic use of gold-containing substances seems possible., D. Košťová, E. Michnová., and Obsahuje bibliografii
Cholestasis is characterized by the elevation of serum total bile acids (TBA), which leads to the production of both free radicals and oxidative stress. Although they do not share the same mechanisms, membrane glycosphingolipids (GSL) and the antioxidant enzyme heme oxygenase-1 (HMOX1) both act against the pro-oxidative effect of TBA. The aim of the study was to assess the role of HMOX on GSL redistribution and composition within hepatocytes in the rat model of estrogen-induced cholestasis. Compared to the controls, an increase of total gangliosides in the liver homogenates of the cholestatic group (P=0.001) was detected; further, it paralleled along with the activation of their biosynthetic b-branch pathway (P<0.01). These effects were partially prevented by HMOX activation. Cholestasis was accompanied by a redistribution of GM1 ganglioside from the cytoplasm to the sinusoids; while HMOX activation led to the retention of GM1 in the cytoplasm (P=0.014). Our study shows that estrogen-induced cholestasis is followed by changes in the synthesis and/or distribution of GSL. These changes are not only triggered by the detergent power of accumulated TBA, but also by their pro-oxidant action. Increases in the antioxidant defenses might represent an important supportive therapeutic measure for patients with cholestatic liver disease., T. Petr, V. Šmíd, V. Kučerová, K. Váňová, M. Leníček, L. Vítek, F. Šmíd, L. Muchová., and Obsahuje bibliografii
T-2 toxin and its metabolite HT-2 toxin are one of the most toxic mycotoxins of type A-trichothecenes, which are produced mainly by Fusarium species. Therefore, study of Fusarium toxins T-2 toxin and HT-2 toxin is an essential issue because they could also play role in failures of reproductive functions as well as endocrine system of domestic animals. Assessment of the effect of A-trichothecene mycotoxin HT-2 toxin alone or combined with insulin-like growth factor (IGF-I), leptin and ghrelin on estradiol secretion by rabbit ovarian fragments in vitro was done. Rabbit ovarian fragments were incubated without (control group) or with HT-2 toxin, or its combinations with IGF-I, leptin and ghrelin at various concentrations for 24 h. Secretion of 17β-estradiol was determined by ELISA. Firstly, HT-2 toxin at the doses 10 and 100 ng.ml-1, but not at 1 ng.ml-1 decreased 17β-estradiol secretion by ovarian fragments. Secondly, 17β-estradiol secretion was not affected by HT-2 toxin exposure combined with growth factor IGF-I, metabolic hormones leptin and ghrelin. In conclusion, HT-2 toxin has potent direct dose-dependent effects on ovarian steroidogenesis in rabbits. These direct effects of HT-2 mycotoxin on ovarian steroidogenesis could impact negatively on the reproductive performance of rabbits., A. Kolesarova, N. Maruniakova, A. Kadasi, M. Halenar, M. Marak, A. V. Sirotkin., and Obsahuje bibliografii
Various protocols may be used for acute pancreatitis treatment. Recently, the benefit of hyperbaric oxygen (HBO) has been demonstrated. To clarify the mechanism of HBO on the process of the acute pancreatitis, we determined the levels of antioxidant enzymes in an acute pancreatitis model. Forty-five Sprague-Dawley rats were randomly divided into three groups: Group I: sham group (n=15), Group II: pancreatitis group (n=15), Group III: pancreatitis group undergoing HBO therapy (n=15). HBO was applied postoperatively for 5 days, two sessions per day at 2.5 fold absolute atmospheric pressure (ATA) for 90 min. Superoxide dismutase (Cu/Zn-SOD), malondialdehyde (MDA), and glutathione peroxidase (GSH Px) activity were measured in pancreatic tissue and erythrocyte lysate. MDA and GSH Px were also determined in plasma. In addition, amylase levels were measured in the serum. While serum amylase levels and MDA values in erythrocyte, plasma and pancreatic tissue were decreased, the levels of GSH Px and SOD were found to be significantly increased in the Group III as compared to those of the Group II. The findings of our study suggest that HBO has beneficial effects on the course of acute pancreatitis and this effect may occur through the antioxidant systems., M. Yasar, S. Yildiz, R. Mas, K. Dundar, A. Yildirim, A. Korkmaz, C. Akay, N. Kaymakcioglu, T. Ozisik, D. Sen., and Obsahuje bibliografii
To evaluate whether the response of hematopoietic cells to interleukin-17 (IL-17) depends on the tissue microenvironment in which hematopoiesis occurs, the influence of recombinant mouse IL-17 on spleen hematopoietic cells and cytokine release was assessed in normal mice in vitro and in vivo. In vitro, IL-17 did not significantly affect the growth of granulocyte-macrophage (CFU-GM) and erythroid (BFU-E and CFU-E) derived colonies. A single injection of IL-17 in vivo exhibited stimulatory effects on hematopoietic cells from both granulocytic and erythroid lineages. The increased number of metamyelocytes 48 h after treatment imply to the IL-17-induced stimulation of granulopoiesis. The number of BFU-E was increased at 24 h, while the number of CFU-E increased 6 h and 24 h after treatment. Since the same treatment in the bone marrow decreased the number of CFU-E, it may be concluded that the local microenvironment plays an important role in IL-17-mediated effects on CFU-E. IL-17 increased the release of IL-6 both in vitro and in vivo, but showed tendency to suppress the constitutive secretion of IL-10 by spleen cells. Our results suggest the complexity of target cell response and interplay of secondary induced cytokines by IL-17 in different hematopoietic organs., G. Jovčić, D. Bugarski, A. Krstić, M. Vlaški, M. Petakov, S. Mojsilović, N. Stojanović, P. Milenković., and Obsahuje bibliografii a bibliografické odkazy