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General Physiology and Biophysics

Volume 35, 2016, No. 1


  Recent advances in iPSC technologies involving cardiovascular and neurodegenerative disease modeling
Mária Csöbönyeiová 1), Lubos Danisovic, Stefan Polak

1)Institute of Histology and Embryology, Faculty of Medicine, Comenius University in Bratislava, Sasinkova 4, 811 08 Bratislava, Slovak Republic.

Cardiovascular and neurodegenerative diseases are the most common health threats in developed countries. Limited cell derivation and cell number in cardiac tissue makes it difficult to study the cardiovascular disease using the existing cardiac cell model. Regarding the neurodegenerative disorders, the most potential sources of cell therapeutics such as fetal-derived primary neurons and human embryonic stem cells (ESCs) are associated with ethical or technical limitations. The successful derivation of human-induced pluripotent stem cells (iPSCs) by de-differentiation of somatic cells offers significant potential to overcome hurdles in the field of the replacement therapy. Human iPSCs are functionally similar to human embryonic stem cells, and can be derived autologously without the ethical challenges associated with human ESCs. The iPSCs can, in turn, be differentiated into all cell types including neurons, cardiac cells, blood and liver cells, etc. Recently, target tissues derived from human iPSCs such as cardiomyocytes (CMs) or neurons have been used for new disease modeling and regenerative medicine therapies. Diseases models could be advantageous in the development of personalized medicine of various pathological conditions. This paper reviews efforts aimed at both the practical development of iPSCs, differentiation to neural/cardiac lineages, and the further use of these iPSCs-derived cells for disease modeling, as well as drug toxicity testing.

General Physiology and Biophysics. Volume 35, 2016, No. 1: 1-12.

  Calcium versus strontium handling by the heart muscle
Michal Hendrych 1), Veronika Olejnickova, Marie Novakova

1)Department of Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.

Calcium plays a crucial role in numerous processes in living systems, from both intracellular and intercellular signalling to blood clotting. Calcium can be replaced by strontium in various intracellular processes due to high level of their similarity and strontium thus may serve as a valuable tool for different experimental studies. On the other hand, strontium is also used in clinical medicine and is commonly taken to the human body with food and water. The negative cardiac side effects of strontium therapy of osteoporosis and bone metastases are well known, but still not fully explained. This fact explains enhanced interest in this element and its impact on human body. This article reviews effects of calcium and strontium on several biochemical and physiological processes, with special emphasis on cardiac muscle.

General Physiology and Biophysics. Volume 35, 2016, No. 1: 13-23.

  Sulforaphene promotes Bax/Bcl2, MAPK-dependent human gastric cancer AGS cells apoptosis and inhibits migration via EGFR, p-ERK1/2 down-regulation
Arindam Mondal 1), Raktim Biswas, Yun-Hee Rhee, Jongkee Kim, Jin-Chul Ahn

1)Beckman Laser Institute Korea, Dankook University, 119, Dandae-ro, Cheonan, Chungnam, 330-714, Republic of Korea.

Gastric cancer migration and invasion considered as main causes of this cancer-related death around the world. Sulforaphene (4-isothiocyanato-4R-(methylsulfinyl)-1-butene), a structural analog of sulforaphane, has been found to exhibit anticancer potential against different cancers. Our aim was to investigate whether dietary isothiocyanate sulforaphene (SFE) can promote human gastric cancer (AGS) cells apoptosis and inhibit migration. Cells were treated with various concentrations of SFE and cell viability, morphology, intracellular ROS, migration and different signaling protein expressions were investigated. The results indicate that SFE decreases AGS cell viability and induces apoptosis in a dose-dependent manner. Intracellular ROS generation, dose- and time-dependent Bax/Bcl2 alteration and signaling proteins like cytochrome c, Casp-3, Casp-8 and PARP-1 higher expression demonstrated the SFE-induced apoptotic pathway in AGS cells. Again, SFE induced apoptosis also accompanied by the phosphorylation of mitogen-activated protein kinases (MAPKs) like JNK and P-38. Moreover, dose-dependent EGFR, p-ERK1/2 down-regulation and cell migration inhibition at non-toxic concentration confirms SFE activity in AGS cell migration inhibition. Thus, this study demonstrated effective chemotherapeutic potential of SFE by inducing apoptisis as well as inhibiting migration and their preliminary mechanism for human gastric cancer management.

General Physiology and Biophysics. Volume 35, 2016, No. 1: 25-34.

  The effect of aerobic exercise on hepatotoxicity induced by intratracheal instillation of iron oxide nanoparticles in Wistar rats
Azadeh Vasili 1), Gholamreza Sharifi, Mohammad Faramarzi, Ali Noori, Shora Yazdanshenas

1)Department of Exercise Physiology, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran.

Iron oxide nanoparticles (IONPs) can cause significant health problems due to their unique physicochemical properties and environmental characteristics. They are found as ultrafine particles in ambient air. After inhalation, these particles move from the lung to phagocytosis tissues, especially the liver. The aim of present study was to investigate the effect of concurrent aerobic exercise and IONPs on liver enzymes and histological hepatic appearance. 48 rats were divided into six groups: experimental 1 (aerobic exercise), experimental 2 (nanoparticle, anesthesia), experimental 3 (aerobic exercise, nanoparticles, anesthesia), placebo 4 (distilled water, anesthesia), placebo 5 (aerobic exercise, anesthesia), and control group. In groups 2 and 3, 40 mg/kg/b.w. of IONPs was injected via intratracheal installation every other day for 14 days. Groups 1, 3, and 4 run on treadmill for 30 minutes with the intensity of 35–40% VO2max (maximal oxygen consumption) every day. ALT was increased in group 1 but decreased in groups 2 and 3. AST was not significant in any of the groups, while ALP was reduced significantly in groups 2 and 3 (p < 0.05). Histological examination of the liver showed that, in groups 2 and 3, hepatic cells were damaged and also the congestion, inflammation, mononuclear cell infiltration, and ballooning degeneration were occurred. Tissue injuries in group 3 were less than those of group 2. These findings indicated that hepatotoxicity was caused by iron oxide nanoparticles; however, low-intensity aerobic exercise could decrease the damage somewhat.

General Physiology and Biophysics. Volume 35, 2016, No. 1: 35-43.

  The cytoprotective effects of ethanol extract of Ecklonia cava against oxidative stress are associated with upregulation of Nrf2-mediated HO-1 and NQO-1 expression through activation of the MAPK pathway
Yung Hyun Choi 1)

1)Department of Biochemistry, Dongeui University College of Korean Medicine, 52-57, Yangjeong-ro, Busanjin, Busan 614-052, Republic of Korea.

The aim of the present study was to examine the cytoprotective effect of Ecklonia cava against oxidative stress in C2C12 myoblasts. The ethanol extract of E. cava (EEEC) prevented hydrogen peroxide (H2O2)-induced inhibition of the growth of C2C12 myoblasts and exhibited scavenging activity against intracellular reactive oxygen species (ROS) induced by H2O2. EEEC treatment attenuated H2O2-induced comet tail formation and phospho-histone γH2A.X expression. Furthermore, EEEC treatment enhanced the level of the phosphorylated form of nuclear factor erythroid 2- related factor 2 (Nrf2) and its nuclear translocation, which was associated with the induction of heme oxygenase-1 (HO-1) and NADPH-quinone oxidoreductase 1 (NQO-1). Zinc protoporphyrin IX, a HO-1 competitive inhibitor, significantly abolished the protective effects of EEEC against H2O2-induced ROS generation and growth inhibition in C2C12 myoblasts. Transient transfection with Nrf2-specific small interfering RNA restored the elevated HO-1 and NQO-1 expression and the phosphorylation of Nrf2 to near normal levels. The EEEC treatment also induced the activation of mitogen-activated protein kinases (MAPKs), and specific inhibitors of MAPKs abolished upregulated HO-1 and NQO-1, as well as the phosphorylation of Nrf2. Taken together, these data suggest that EEEC attenuates oxidative stress by activating Nrf2-mediated HO-1 and inducing NQO-1 via the activation of MAPK signaling pathways.

General Physiology and Biophysics. Volume 35, 2016, No. 1: 45-53.

  Concept of relative variability of cardiac action potential duration and its test under various experimental conditions
János Magyar 1), Kornél Kistamás, Krisztina Váczi, Bence Hegyi, Balázs Horváth, Tamás Bányász, Péter Nánási, Norbert Szentandrássy

1)Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O.Box 22, Hungary.

Beat-to-beat variability of action potential duration (short-term variability, SV) is an intrinsic property of mammalian myocardium. Since the majority of agents and interventions affecting SV may modify also action potential duration (APD), we propose here the concept of relative SV (RSV), where changes in SV are normalized to changes in APD and these data are compared to the control SV-APD relationship obtained by lengthening or shortening of action potentials by inward and outward current injections. Based on this concept the influence of the several experimental conditions like stimulation frequency, temperature, pH, redox-state and osmolarity were examined on RSV in canine ventricular myocytes using sharp microelectrodes. RSV was increased by high stimulation frequency (cycle lengths <0.7 s), high temperature (above 37ºC), oxidative agents (H2O2), while it was decreased by reductive environment. RSV was not affected by changes in pH (within the range of 6.4–8.4) and osmolarity of the solution (between 250–350 mOsm). The results indicate that changes in beat-to-beat variability of APD must be evaluated exclusively in terms of RSV; furthermore, some experimental conditions, including the stimulation frequency, redox-state and temperature have to be controlled strictly when analyzing alterations in the short-term variability of APD.

General Physiology and Biophysics. Volume 35, 2016, No. 1: 55-62.

  Cardioprotective effect of postconditioning against ischemia-reperfusion injury is lost in heart of 8-week diabetic rat
Hande Altunkaynak 1), Arif Ozcelikay

1)Department of Pharmacology, Faculty of Medicine, Baskent University, Ankara, Turkey.

Although ischemic preconditioning (IPC) and ischemic postconditioning (IPost) result in protection against ischemia-reperfusion (I/R) injury in healthy hearts, pathological conditions such as diabetes can modify the protective effects of IPC and IPost. There are a few studies concerning the effect of IPost only in diabetic hearts which have similar or decreased tolerance to I/R injury. In the present study we investigated the effects of IPost in diabetic hearts which had increased tolerance to I/R injury. Isolated hearts from control and diabetic rats were subjected to global ischemia (40 min) followed by reperfusion (40 min). IPost was induced by six cycles (10 s) of reperfusion and ischemia after the global ischemia. After I/R, cardiac recovery in diabetic hearts was better than that in control hearts. IPost did not produce any further protection in the diabetic hearts whereas it resulted in a significant recovery in the control hearts. Similarly, the decreased troponin I (TnI) levels of diabetic hearts did not change after IPost. However, IPost significantly lowered the increase in TnI levels of control hearts. In conclusion, these results show that IPost can not produce a further protection in the hearts of 8-week diabetic rats which have increased tolerance to I/R injury.

General Physiology and Biophysics. Volume 35, 2016, No. 1: 63-69.

  The influence of zinc on the blood serum of cadmium-treated rats through the rheological properties
Sherif Moussa 1), Abdulaziz Alaamer, Mohamed Abdelhalim

1)Department of Physics, College of Science, Al Imam Mohammad Ibn Saud Islamic University, Riyadh 11623, Saudi Arabia.

The blood rheological properties serve as an important indicator for the early detection of many diseases. This study aimed to investigate the influence of zinc (Zn) on blood serum of cadmium (Cd) intoxication-treated male rats through the rheological properties. The rheological parameters were measured in serum of control, Cd, and Cd+Zn groups at wide range of shear rates (225–1875 s–1). The rat blood serum showed a non-significant change in cadmium-treated rats' %torque and shear stress at the lower shear rates (200–600 s–1) while a significant increase was observed at the higher shear rates (650–1875 s–1) compared with the control. The rat blood serum viscosity increased significantly in the Cd-treated group at each shear rate compared with the control. The viscosity and shear rate exhibited a non-Newtonian behavior for all groups. The increase in blood serum viscosity in Cd-treated male rats might be attributed to destruction or changes in the non-clotting proteins, and other blood serum components. In Cd+Zn-treated rats, the rat blood serum viscosity values returned nearer to the control values at each shear rate. Our results confirmed that Zn displaced Cd or compete with the binding sites for Cd uptake.

General Physiology and Biophysics. Volume 35, 2016, No. 1: 71-75.

  Remote limb ischemic preconditioning (rIPC) activates antioxidant and antiapoptotic genes and inhibits proinflammatory cytokine genes in renal ischemia/reperfusion injury
Abdelaziz Hussein 1), Ahmed Harraz, Amira Awadalla, Nashwa Barakat, Shery Khater, Ahmed Shokeir

1)Physiology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt.

The mechanisms underlying the renoprotective effect for remote limb ischemic preconditioning (rIPC) against renal ischemia/reperfusion injury need further elucidation. In our work, one hundred and twenty male Sprague Dawley rats were randomized into 3 groups; sham, I/R group (left renal 45 min ischemia) and rIPC (as I/R group with 3 cycles of left femoral ischemic PC just before renal ischemia). Rats were sacrificed at 2 h, 24 h, 48 h and 7 days. Serum creatinine and urea were measured at the baseline and endpoints. Also, histopathological examination and assessment of the expression of inflammatory cytokines e.g. TNF-α, IL-1β and ICAM-1 and antioxidant genes: Nrf2, HO-1 and NQO-1 and anti-apoptotic gene Bcl-2 in left kidney were done by the end of experiment. The results of this study demonstrated that, rIPC caused significant improvement in serum creatinine and BUN levels and in the expression of antioxidant genes and Bcl-2 antiapoptotic gene with significant attenuation of pro-inflammatory cytokines and histopathological damage score at all-time points compared to I/R group (p ≤ 0.05). In conclusion, inhibition of inflammatory cytokine (TNF-α, IL-1β and ICAM-1) formation and activation of antioxidant genes: Nrf2, HO-1 and NQO-1 and anti-apoptotic gene Bcl-2 could be possible underlying mechanisms for the renoprotective effect of rIPC.

General Physiology and Biophysics. Volume 35, 2016, No. 1: 77-86.

  Effect of crocin on oxidative stress in recovery from single bout of swimming exercise in rats
Eyup Altinoz 1), Tarık Ozmen, Zulal Oner, Hulya Elbe, Mehmet Erdemli, Harika Bag

1)Department of Medical Biochemistry, Medical Faculty, Karabuk University, Karabuk, Turkey.

Physical exercise could cause muscle and tissue damage due to increase in the formation of free oxygen radicals during exercise. The aim of the present study was to investigate the effect of crocin on parameters associated with oxidative stress in recovery from acute swimming exercise in rats. Rats were divided into eight groups; Normal Control (NC: untreated and did not swim), Crocin Control (CC: received crocin and did not swim), Exercise-1 (Exe-1: untreated and swam), Exercise-24 (Exe-24: untreated and swam), Exercise-48 (Exe-48: untreated and swam), Exercise+Crocin-1 (Exe-Cro-1: received crocin and swam), Exercise+Crocin-24 (Exe-Cro-24: received crocin and swam), Exercise+Crocin-48 (Exe-Cro-48: received crocin and swam). AST, ALP, LDH, CK, XO enzymes levels increased after swimming in untreated and crocin-treated groups, but there was a less increase in crocin-treated groups. The highest MDA levels in serum were determined in Exe-1 compared with all other groups. There was significant difference between control and exercise groups in MDA level (p = 0.033). In contrast, there was significant difference between control and exercise groups in GSH level (p < 0.001). In addition, crocin given to swimming rats significantly increased GSH levels (p < 0.05) and decreased MDA levels when compared with untreated exercise groups. In conclusion, crocin is able to protect liver and skeletal muscle tissue against exercise-induced oxidative damage by preventing reactive oxygen species (ROS) production.

General Physiology and Biophysics. Volume 35, 2016, No. 1: 87-94.

  Properties of anaerobic fungi isolated from several habitats: complexity of phenotypes
Viera Zelená 1), Lucia Birošová, Petra Olejníková, Martin Polák, Boris Lakatoš, Ľudovít Varečka

1)Department of Biochemistry and Microbiology, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 811 02 Bratislava, Slovak Republic.

Isolates of anaerobic fungi from rumen, animal faeces and compost displayed morphological similarity with known anaerobic fungi. According to their ITS sequences, species were related to Neocallimastix and Piromyces. Rumen fungi tolerated exposure to an aerobic atmosphere for at least four days. Under anaerobic conditions, they could grow on both, defined or complex substrates. Growth in liquid media was monitored by the continuous measurement of metabolic gases (O2, CO2, H2, CO, H2S, CH4). Monitored metabolism was complex, showed that both CO2 and H2 were produced and subsequently consumed by yet unknown metabolic pathway(s). CO and H2S were evolved similarly, but not identically with the generation of CO2 and H2 suggesting their connection with energetic metabolism. Anaerobic fungi from snail faeces and compost produced concentrations of H2S, H2, CO near the lower limit of detection. The rumen isolates produced cellulases and xylanases with similar pH and temperature optima. Proteolytic enzymes were secreted as well. Activities of some enzymes of the main catabolic pathways were found in cell-free homogenates of mycelia. The results indicate the presence of the pentose cycle, the glyoxylate cycle and an incomplete citrate cycle in these fungi. Differences between isolates indicate phenotypic variability between anaerobic fungi.

General Physiology and Biophysics. Volume 35, 2016, No. 1: 95-107.

  Stress increased ghrelin secretion from pancreatic isolated islets in male rats
Fatemeh Rostamkhani 1), Homeira Zardooz, Fatemeh Goshadrou, Mahyar Baveisi, Mehdi Hedayati

1)Department of Biology, College of Basic Sciences, Yadegar-e-Imam Khomeini (RAH) Shahre Rey Branch, Islamic Azad University, Tehran, Iran.

It has been demonstrated that plasma ghrelin is likely affected by stress, but little attention has been paid to the effect of stress on ghrelin release from pancreatic islets. This study investigates the effect of stress on ghrelin secretion from pancreatic islets in rats. Male Wistar rats were divided into control and stressed groups. The stressed group was further divided into foot-shock and psychological stress subgroups. Stress was induced by a communication box. After stress exposure, blood sampling was performed to determine the plasma levels of corticosterone, glucose, and ghrelin. Then the animals’ pancreatic islets were isolated to assess their ghrelin output at 5.6, 8.3, and 16.7 mM glucose concentrations. Acute exposure to foot-shock and psychological stress both increased plasma corticosterone concentration. Moreover, plasma glucose concentration increased in the foot-shock stress group. Chronic exposure to foot-shock decreased plasma ghrelin concentration, whereas acute exposure had no significant effect. Acute and chronic exposure to foot-shock and psychological stress increased ghrelin secretion from isolated islets in the presence of different glucose concentrations. The results of the present study suggest that ghrelin secretion from isolated islets is not glucose-dependent. However, ghrelin secretion appears to be intensely responsive to both acute and chronic stress.

General Physiology and Biophysics. Volume 35, 2016, No. 1: 109-117.