Role of Atrial Natriuretic Peptide in Oxytocin Induced Cardioprotection

Background The purpose of this study was to determine whether endogenous atrial natriuretic peptide (ANP) contributes to the protective effect of neurohypophysial hormone oxytocin (OT) in heart preconditioning. Methods Sprague-Dawley male rats were subjected to 25 min regional ischaemia and 120 min reperfusion and were divided into eight groups. Oxytocin or an equivalent volume of saline was administrated intraperitoneally, 30 min before ischaemia. The OT receptor antagonist (atosiban), ANP receptor antagonist (anantin) and nitric oxide synthase inhibitor (L-NAME) were injected 10 min before OT. In other groups, atosiban, anantin and L-NAME were only administered 40 min prior to ischaemia. Results Compared with the ischaemia/reperfusion group (I/R), alterations in infarct size, biochemical parameters LDH (lactate dehydrogenase), CK-MB (creatine kinase-MB), MDA (malondialdehyde) plasma levels] and severity of ventricular arrhythmia due to I/R injury were attenuated and VF was abolished by OT treatment. These OT effects were eliminated by OT and ANP receptor blockers and nitric oxide synthase inhibitor, but anantin did not reverse the effect of OT in lipid peroxidation. Conclusions These findings demonstrate an important contributory role of ANP in the OT induced protection in myocardial ischaemia reperfusion. OT also reduced lipid peroxidation with a NO-dependent mechanism

The Role of Oxytocin on Cardiac Ischemia-ReperfusionInduced Oxidative Stress in Rats

Abstract Introduction: Oxidative stress is caused by the imbalance between production of pro-oxidants and the antioxidant defenses. Reactive oxygen species (ROS) can play an important role in the pathogenesis of cardiovascular diseases. The present study aimed at investigating whether administration of oxytocin ameliorates oxidative stress induced by experimental myocardial infarction in rats. Materials and Methods: Cardiac ischemia-reperfusion (I/R) was induced by occlusion of left main coronary artery of rats for 25 min, followed by a period of reperfusion for 2h. OT at doses of 0.0001-1 µg was administered intraperitoneally 30 min prior to ischemia. Following reperfusion, blood samples were taken for measuring the plasma MDA levels, as an index of lipid peroxidation. Results: We observed a dose-dependent association between dose of oxytocin and plasma MDA. Oxytocin 0.01µg significantly reduced MDA levels as compared to control group. Blockade of specific OT receptors by atosiban attenuated the anti-oxidative effect of OT. The MDA level in the L-NAME and atropine groups were higher than those in the OT group and reach to control group, whereas the MDA levels in the anantin group were same as OT group and significantly lower than those in the control group. Conclusions: Oxytocin has a beneficial effect, mediated by NO and Ach, on cardiac tissue against oxidative damage due to I/R, suggesting that oxytocin can be used to tissue protection against oxidative stress

Effects of selegiline, a monoamine oxidase B inhibitor, on differentiation of P19 embryonal carcinoma stem cells, into neuron-like cells

Selegiline, the irreversible inhibitor of monoamine oxidase B (MAO-B), is currently used to treat Parkinson's disease. However, the mechanism of action of selegiline is complex and cannot be explained solely by its MAO-B inhibitory action. It stimulates gene expression, as well as expression of a number of mRNAs or proteins in nerve and glial cells. Direct neuroprotective and antiapoptotic actions of selegiline have previously been observed in vitro. Previous studies showed that selegiline can induce neuronal phenotype in cultured bone marrow stem cells and embryonic stem cells. Embryonal carcinoma (EC) cells are developmentaly pluripotene cells which can be differentiated into all cell types under the appropriate conditions. The present study was carried out to examine the effects of selegiline on undifferentiated P19 EC cells. The results showed that selegiline treatment had a dramatic effect on neuronal morphology. It induced the differentiation of EC cells into neuron-like cells in a concentration-dependent manner. The peak response was in a dose of selegiline significantly lower than required for MAO-B inhibition. The differentiated cells were immunoreactive for neuron-specific proteins, synaptophysin, and beta-III tubulin. Stem cell therapy has been considered as an ideal option for the treatment of neurodegenerative diseases. Generation of neurons from stem cells could serve as a source for potential cell therapy. This study suggests the potential use of combined selegiline and stem cell therapy to improve deficits in neurodegenerative diseases

Neuronal differentiation of GFP expressing P19 embryonal carcinoma cells by deprenyl, an antiparkinson drug

زمینه و هدف: سلول های P19 دودمانی از سلول های کار سینومای جنینی چند استعدادی هستند که قادرند در محیط کشت حاوی سرم رشد نموده و برای تمایز به هر سه دودمان مزودرمی، آندودرمی و اکتودرمی القا شوند. با استفاده از روش های استاندارد ترانسفکشن می توان توالی DNA خارجی را به این سلول ها وارد کرده و عملکرد و تمایز سلولی را بررسی کرد. این تحقیق با هدف القای فنوتیپ عصبی در سلول های P19 ترانسفکت شده با ژن پروتئین فلوئورسانت سبز (GFP) با استفاده از داروی ضد پارکینسونی دپرنیل صورت گرفت. روش بررسی: در این مطالعه توصیفی آزمایشگاهی از روش رسوب کلسیم فسفات جهت وارد کردن پلاسمید pML8 حاوی ژن GFP و ژن مقاوم به پیورومایسین به این سلول ها استفاده شد. سلول ها با استفاده از محیط کشت MEM-A (Minimum Essential Medium Alpha) حاوی 15 درصد سرم گاوی جنینی کشت داده شدند. در اینجا غلظت 8-10 مولار دپرنیل برای القای تمایز اجسام شبه جنینی به دودمان عصبی استفاده شد. جهت ارزیابی تمایز سلول های P19 بررسی موفولوژی با استفاده از رنگ آمیزی اختصاصی کرزیل ویوله انجام شد. به علاوه برای ردیابی پروتئین های ویژه سلول های عصبی مانند سیناپتوفیزین و بتاتوبولین III از روش ایمنوفلورسنس استفاده شد. یافته ها: ضمن تولید سلول های P19 ترانسفکت شده پایدار، تمایز عصبی این سلول ها تحت تأثیر عامل القایی دپرنیل انجام شد. نورون های GFP مثبت مشتق شده از سلول های کار سینومای جنینی نشانگرهای ویژه سلول های عصبی را بیان کردند. نتیجه گیری: سلول های تمایز یافته GFP مثبت می توانند در مطالعات پیوندی و پژوهش های پایه ای مرتبط با سلول درمانی و بیماری های تحلیل سیستم عصبی مورد استفاده قرار گیرند

The role of central oxytocin in stress-induced cardioprotection in ischemic-reperfused heart model

Background and purpose: There is growing evidence that stress contributes to cardiovascular disease and triggers the release of oxytocin. Moreover previous studies confirmed oxytocin mimics the protection associated with ischemic preconditioning. The present study was aimed to assess the possible cardioprotective effects of the centrally released oxytocin in response to stress and intracerebroventricular (i.c.v.) administration of exogenous oxytocin in ischemic-reperfused isolated rat heart. Methods and subjects: Rats were divided in two main groups and all of them were subjected to i.c.v. infusion of vehicle or drugs: unstressed rats control: vehicle, oxytocin (OT; 100 ng/5 mu l), atosiban (ATO; 4.3 mu g/5 mu l) as oxytocin antagonist, ATO + OT] and stressed rats St: stress, OT + St, ATO + St]. After anesthesia, hearts were isolated and subjected to 30 min regional ischemia and 60 min reperfusion (IR). Acute stress protocol included swimming for 10 min before anesthesia. Myocardial function, infarct size, coronary flow, ventricular arrhythmia, and biochemical parameters such as creatine kinase and lactate dehydrogenase were measured. Ischemia-induced ventricular arrhythmias were counted during the occlusion period. Results: The plasma levels of oxytocin and corticosterone were significantly elevated by stress. Unexpectedly hearts of stressed rats showed a marked depression of IR injury compared to control group. I.c.v. infusion of oxytocin mimicked the cardioprotective effects of stress, yet did not elevate plasma oxytocin level. The protective effects of both stress and i.c.v. oxytocin were blocked by i.c.v. oxytocin antagonist. Conclusions: These findings suggest that i.c.v. infusion of exogenous oxytocin and centrally released endogenous oxytocin in response to stress could play a role in induction of a preconditioning effect in ischemic-reperfused rat heart via brain receptors. (C) 2012 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved

Metformin accelerates myelin recovery and ameliorates behavioral deficits in the animal model of multiple sclerosis via adjustment of AMPK/Nrf2/mTOR signaling and maintenance of endogenous oligodendrogenesis during brain self-repairing period

BACKGROUND: Multiple sclerosis (MS) is a devastating autoimmune disorder characterized by oligodendrocytes (OLGs) loss and demyelination. In this study, we have examined the effects of metformin (MET) on the oligodendrogenesis, redox signaling, apoptosis, and glial responses during a self-repairing period (1-week) in the animal model of MS. METHODS: For induction of demyelination, C57BL/6 J mice were fed a 0.2% cuprizone (CPZ) for 5 weeks. Thereafter, CPZ was removed for 1-week and molecular and behavioral changes were monitored in the presence or absence of MET (50 mg/kg body weight/day). RESULTS: MET remarkably increased the localization of precursor OLGs (NG2+/O4+ cells) and subsequently the renewal of mature OLGs (MOG+ cells) in the corpus callosum via AMPK/mammalian target of rapamycin (mTOR) pathway. Moreover, we observed a significant elevation in the antioxidant responses, especially in mature OLGs (MOG+/nuclear factor erythroid 2-related factor 2 (Nrf2+) cells) after MET intervention. MET also reduced brain apoptosis markers and lessened motor dysfunction in the open-field test. While MET was unable to decrease active astrogliosis (GFAP mRNA), it reduced microgliosis by down-regulation of Mac-3 mRNA a marker of pro-inflammatory microglia/macrophages. Molecular modeling studies, likewise, confirmed that MET exerts its effects via direct interaction with AMPK. CONCLUSIONS: Altogether, our study reveals that MET effectively induces lesion reduction and elevated molecular processes that support myelin recovery via direct activation of AMPK and indirect regulation of AMPK/Nrf2/mTOR pathway in OLGs. These findings facilitate the development of new therapeutic strategies based on AMPK activation for MS in the near future. KEYWORDS: AMPK; Cuprizone; Multiple sclerosis; Nrf2; mTO

Protective effect of carvacrol against hepato-renal toxicity induced by azathioprine in rats

Background and aims: Azathioprine (AZA) is an immunosuppressant medication that has toxicity to kidneys and liver. This study aimed to investigate the protective activity of carvacrol (CAR) against hepatorenal toxic activity of AZA in male Wistar rats. Methods: All study rats were divided into five groups: control (saline, ip); azathioprine-only (AZA 50 mg/kg, ip), Sily+AZA (Silymarin 50 mg/kg, gavage), CAR+AZA (CAR 10 mg/kg, gavage), and CAR+AZA (CAR 20 mg/kg, gavage) groups. Silymarin was used as the standard hepatoprotective drug. The drugs were administered once daily for 21 days in III-V groups, and a single dose of AZA was injected on the seventh day of the experiment. Results: AZA-intoxicated rats exhibited an elevation in aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP) activity in serum, as well as an increase in extent of lipid peroxidation. Activities of enzymatic antioxidants (superoxide dismutase – SOD, catalase - CAT) in the serum, liver, and kidney were decreased as for the AZA group (P<0.05). Co-treatment of CAR (both doses of 10 and 20 mg/kg) lowered the serum transaminases and ALP level, the elevation of endogenous enzymes levels, and the malondialdehyde (MDA) in serum and both tissues (P<0.05). This protective effect was greater in CAR 10 compared to 20 mg/kg doses, which was comparable to silymarin. Conclusion: This study demonstrated that the renal and nephrotoxic activities of AZA could be attributed to the generated increased oxidative stress, as well as to the CAR with antioxidant effect similar to that in silymarin, which protected these tissues against AZA-induced nephrotoxicity hepatotoxicity. Keywords: Azathioprine, Carvacrol, Silymarin, Nephrotoxicity, Hepatotoxicit

Designing and establishment of ISO/IEC 17025 in laboratories of national inland water aquaculture center and south Iran aquaculture research center

The project was carried out between June of 2011 and November of 2012,8 laboratories of research center in Anzali (Plankton, Algae, Hydrochemistry, Physiology, Ichthyology, Bentose, Parazitology, Virology) and 7 laboratories of research center in Ahvaz (Clinical pathology, Plankton, Hydrochemistry, Physiology, Ichthyology, Bentose, Parazitology, Virology) were selected for accreditation. The main stages for establishment of the system consisted of: 1-Conducting a gap analysis to compare the present state of the laboratories with ISO/IEC 17025 2-Training General requirements for the competence of testing and calibration laboratories Validation of methods Estimation of uncertainty Internal audits 3- Performing of technical and management requirements 4-Submit of quality manual to ASCB center in England in order to accredit In August of 2012 The main results were including: 1-Increase the accuracy of measurement in laboratories 2-Improvement of the Repeatability and Reproducibility of the test methods 3-Traceability and standardization of test methods 4- Calibration of measurement instruments 6- Updating of test methods 7-Standardization of physical condition of the laboratories 8- Getting the certification from ASCB center i

Differentiation of P19 embryonal carcinoma stem cells into insulin-producing cells promoted by pancreas-conditioned medium

The ability of embryonal carcinoma)EC (stem cells to generate insulin-producing cells (IPCs) is still unknown. We examined the trophic effects of pancreas-conditioned medium (PCM) on in vitro production of IPCs. Initially, P19 EC cells were characterized by the expression of stem cell markers, Oct3/4, Sox-2 and Nanog. To direct differentiation, P19-derived embryoid bodies (EBs) were induced by selection of nestin-positive cells and treatment with different concentrations of PCM. Morphological studies documented the presence of islet-like cell IPCs clusters. The differentiated cells were immunoreactive for β cell-specific proteins, including insulin, proinsulin, C-peptide and insulin receptor-β. The expression of genes related to pancreatic β cell development and function (PDX-1, INS1, INS2, EP300 and CREB1) was confirmed by qPCR. During differentiation, the expression of EP300 and CREB1 increased by 2.5 and 3.1 times, respectively. In contrast, a sharp decrease in the expression of Oct3/4, Sox-2 and Nanog by 4, 1.5 and 1.5 times, respectively, was observed. The differentiated cells were functionally active, synthesizing and secreting insulin in a glucose-regulated manner. Network prediction highlighted crosstalk between PDX-1 transcription factor and INS2 ligand in IPC generation and revealed positive regulatory effects of EP300, CREB1, PPARA, EGR, KIT, GLP1R, and PKT2 on activation of PDX-1 and INS2. This is the first report of the induction of IPC differentiation from EC cells by using neonate mouse PCM. Since P19 EC cells are widely available, easily cultured without feeders and do not require special growth conditions, they would provide a valuable tool for studying pancreatic β cell differentiation and development

Effect of different doses of oxytocin on cardiac electrophysiology and arrhythmias induced by ischemia

The onset of acute myocardial ischemia (MI) is accompanied by a rapid increase in electrical instability and often fatal ventricular arrhythmias. This study investigated that whether oxytocin (OT) can modulate ischemia-induced arrhythmias and considered relationships between the severity of arrhythmia and the electrocardiogram parameters during ischemia. OT (0.0001–1 μg) was administrated intraperitoneally 30 min before ischemia. To examine receptor involved, a selective OT-receptor antagonist, atosiban (ATO), was infused 10 min before OT. OT caused a significant and biphasic dose-dependent reduction in ectopic heart activity and arrhythmia score. OT doses that reduced ventricular arrhythmia elicited significant increase in QT interval. OT attenuated the electrophysiological changes associated with MI and there was significant direct relationship between QRS duration and arrhythmia score. ATO treatment reduced beneficial effects of OT on arrhythmogenesis. Nevertheless, ATO failed to alter OT effects on premature ventricular contractions. We assume that the ability of OT to modulate the electrical activity of the heart may play an important role in the antiarrhythmic actions of OT