The goal of the study was to determine whether postconditioning protects against different ischemia durations in the rabbit. Rabbits were assigned to a 20-, 25-, 45- or 60-min coronary occlusion followed by 24-h of reperfusion. Rabbits received no further intervention (control) or were postconditioned with four cycles of 30-s occlusion and 30-s reperfusion after myocardial infarction. Plasma levels of troponin I were quantified throughout reperfusion. In control conditions, infarct sizes (% area at risk using triphenyltetrazolium chloride) after 20, 25, 45 and 60 min of coronary occlusions were 23±3, 51±4, 70±3 and 81±3 %, respectively. With 20 and 25 min occlusion, postconditioning reduced infarct size by 43±10 and 73±21 %, respectively. On the other hand, with 45 or 60 min occlusion, postconditioning had no significant effects on infarct size (61±3 and 80±2 % of area at risk). Preconditioning protocol was performed with 25- and 60-min coronary occlusion. As expected, preconditioning significantly reduced infarct size. In conclusion, in the rabbit, the cardioprotection afforded by postconditioning is limited to less than 45 min coronary occlusion., R. Létienne, Y. Calmettes, B. Le Grand., and Obsahuje seznam literatury
Application of knowledge about ischemic tolerance to clinic requires the solid understanding of mechanism of creation of this phenomenon. This review summarizes research that has been carried out in many laboratories over a long period of time, but the main focus will be on own experimental research. The main emphasis is devoted to the possibility of preparing full tolerance in the donor's body and its transfer to the patient in the form of activated blood plasma. Such plasma could be administered as soon as the patient is transported to the hospital and would take effect immediately after administration to the patient's bloodstream. One chapter is also devoted to anticonditioning, i.e. the possibility of preventing the activation of tolerance. Anticonditioning could be used to treat oncologic patients. We expect that this method could increase effectiveness of cancer treatment. Cross-tolerance with a wide range of diverse stressors gives us the courage to assume that activated plasma can significantly help with a wide range of pathological events., Jozef Burda, Rastislav Burda., and Obsahuje bibliografii
Perinatal hypoxemia may have serious long-term effects on the adult cardiovascular system and may lead to sex-dependent changes in cardiac tolerance to acute ischemia in adult life. The aim of the study was to answer the question whether gonadectomy of the male and female rats in the early phase of ontogenetic development affects the late effect of perinatal hypoxia. Pregnant Wistar rats were placed into a normobaric hypoxic chamber (12 % O2) 7 days before the expected date of delivery. Newborn pups were kept in the chamber with their mothers for another 5 days after birth. After hypoxic exposure all animals were kept for 3 months in room air. Some of the pups were gonadectomized right after removal from the hypoxic chamber. Ventricular arrhythmias were assessed on isolated perfused hearts. Castration did not influence arrhythmogenesis in the adult normoxic or perinatally hypoxic female hearts. Nevertheless, the number of arrhythmias was decreased in perinatally hypoxic gonadectomized males. In conclusion, we have shown that perinatal normobaric hypoxia increased cardiac tolerance to acute ischemia in adult male rats; however, it had no late effect in females. Gonadectomy did not affect arrhythmogenesis in both normoxic and hypoxic female hearts, whereas in males significantly decreased the number of arrhythmias., I. Netuka ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Motion artefact (MA) in voltage-sensitive fluorescent signals causes significant debasement of action potential. During ischemia and reperfusion in isolated rabbit heart, this artefact develops in a manner which may be described by the time of its onset, level, and shape. The MA during ischemia: (a) may become substantial with approximately two minutes delay after establishing global ischemia; (b) may be almost twice as high as the physiological action potential and decreases both with time and repetition of ischemia; (c) the MA shape is unpredictable and depends on individual rabbit., O. Janoušek, ... [et al.]., and Obsahuje seznam literatury
Chronic intermittent hypoxia (CIH ) is associated with increased production of reactive oxygen species that contributes to the adaptive mechanism underlying the improved myocardial ischemic tolerance. The aim was to find out whether the antioxidative enzyme manganese superoxide dismutase (MnSOD) can play a role in CIH-induced cardioprotection. Adult male Wistar rats were exposed to intermittent hypobaric hypoxia (7000 m, 8 h/day, 25 exposures) (n=14) or kept at normoxia (n=14). Half of the animals from each group received N-acetylcysteine (NAC, 100 mg/kg) daily before the hypoxic exposure. The activity and expression of MnSOD were increased by 66 % and 23 %, respectively, in the mitochondrial fraction of CIH hearts as compared with th e normoxic group; these effects were suppressed by NAC treatment. The negative correlation between MnSOD activity and myoc ardial infarct size suggests that MnSOD can contribute to the improved ischemic tolerance of CIH hearts., P. Balková ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Recent studies demonstrated remote effects of renal ischemia/reperfusion (I/R) injury on some organs such as brain, liver, and lungs. We investigated the effects of renal I-R injury on function, histology and oxidative stress state of pancreas. Twenty -four male adult Sprague-Dawley rats were divided equally into 2 groups; sham group: rats underwent midline laparotomy and dissection of renal pedicles without renal ischemia, and ischemic group: rats underwent bilateral renal ischemia for 45 min. Renal functions (serum creatinine and BUN), pancreatic functions (serum amylase, lipase and insulin) and fasting blood glucose were measured at 2 h, 1 day, 3 days and 7 days after ischemia. Also, pancreatic histology and malondialdehyde (MDA), catalase and reduced glutathione (GSH) were examined at 2 h and 7 days after ischemia. The ischemic rats showed significant increase in serum creatinine and BUN with significant increase in serum amylase and lipase at 2 h, 1 day and 3 days after ischemia. Blood glucose and fasting insulin showed no significant change apart from significant increase in insulin in sham group at 1 day after ischemia. Pancreas isolated from ischemic rats showed significant increase in histopathological damage score and significant increase in MDA and catalase enzyme with decrease in GSH. In conclusion, bilateral renal ischemia for 45 min caused significant impairment of pancreatic functions and histology. This might be due to deficiency of antioxidant and increased lipid peroxidations in pancreatic tissues., A. M. Hussein ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
The pathological potential of glial cells was recognized already by Rudolf Virchow, Santiago Ramon y Cajal and Pio Del Rio-Ortega. Many functions and roles performed by astroglia in the healthy brain determine their involvement in brain diseases; as indeed any kind of brain in sult does affect astrocytes, and their performance in pathological conditions, to a very large extent, determines the survival of the brain parenchyma, the degree of damage and neurological defect. Astrocytes being in general responsible for overall brain homeostasis are involved in virtually every form of brain pathology. Here we provide an overview of recent developments in identifying the role and mechanisms of the pathological potential of astroglia., A. Chvátal, M. Anděrová, H. Neprašová, I. Prajerová, L. Benešová, O. Butenko, A. Verkhratsky., and Obsahuje bibliografii a bibliografické odkazy
Microparticles are small fragments of the plasma membrane released by activated and/or apoptotic cells. In theory, all type of cells can shed microparticles representing a physiological process in the cell life. Mainly, microparticles generation has been studied in different cardiovascular pathologies due to the facility to obtain blood samples from individuals. Although microparticles have been considered as simply markers of several diseases, in the last decade, several studies support the hypothesis that they participate in the regulation of the cardiovascular system function by carrying biological messages between cells. Among the effects of microparticles, recent data show that they can be implicated in the modulation of neovascularization, an essential function of cells from cardiovascular system during either ischemic diseases or cancer development. Whereas during pathologies associated with ischemia an increase of neovascularization may have beneficial effects, anti-angiogenic strategies represent new approaches for manipulation of tumor development. Here, we give an overview of the mechanisms and factors involved in neovascularization, and finally, we look at the role and the consequences of the modulation of this process by microparticles in pathological situations., H. A. Mostefai, R. Andriantsitohaina, M. C. Martínez., and Obsahuje bibliografii a bibliografické odkazy
This study was designed to determine the gastroprotective properties of quercetin in ischemia/reperfusion-induced gastric mucosal injury and the involvement of endogenous prostaglandins in this process. Oral pretreatment of rats with quercetin (100 mg.kg-1) 30 min before surgery significantly decreased the length of gastric mucosal lesions. However, lower doses of quercetin (25 and 50 mg.kg-1) only slightly decreased the gastric mucosal injury. Intraperitoneal application of indomethacin (5 mg.kg-1) had no effect in control (sham-operated) animals, but significantly worsened gastric injury in non-treated animals after ischemia/reperfusion. Furthermore, indomethacin only slightly reversed protective effect of quercetin. Non-treated animals showed a marked decrease in adherent mucus after ischemia/reperfusion. On the other hand, application of quercetin prevented this significant decrease even in animals pretreated with indomethacin. It can be concluded that antioxidant properties of quercetin and its mucus protective effect might be the main factors responsible for its protective effect against ischemia/reperfusion-induced gastric mucosal injury., J. Mojžiš, K. Hviščová, D. Germanová, D. Bukovičová, L. Mirossay., and Obsahuje bibliografii
Remifentanil is a commonly used opioid in anesthesia with cardioprotective effect in ischemia-reperfused (I/R) heart. We evaluated the influence of remifentanil on myocardial infarct size and expressions of proteins involved in apoptosis in I/R rat heart following various time protocols of remifentanil administration. Artificially ventilated anesthetized Sprague-Dawley rats were subjected to a 30 min of left anterior descending coronary artery occlusion followed by 2 h of reperfusion. Rats were randomly assigned to one of five groups; Sham, I/R only, remifentanil preconditioning, postconditioning and continuous infusion group. Myocardial infarct size, the phosphorylation of ERK1/2, Bcl2, Bax and cytochrome c and the expression of genes influencing Ca2+ homeostasis were assessed. In remifentanil-administered rat hearts, regardless of the timing and duration of administration, infarct size was consistently reduced compared to I/R only rats. Remifentanil improved expression of ERK 1/2 and anti-apoptotic protein Bcl2, and expression of sarcoplasmic reticulum genes which were significantly reduced in the I/R rats only. Remifentanil reduced expression of pro-apoptotic protein, Bax and cytochrome c. These suggested that remifentanil produced cardioprotective effect by preserving the expression of proteins involved in anti-apoptotic pathways, and the expression of sarcoplasmic reticulum genes in I/R rat heart, regardless of the timing of administration., H. S. Kim ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy