Investigating the challenges and factors influencing the use of the learning management system during the Covid-19 pandemic in Afghanistan.

Successful implementation and use of learning management systems (LMSs) have become a critical challenge for many higher education institutes during the Covid-19 pandemic. Although LMSs with lots of features were developed for universities, the success of those systems is highly related to a detailed understanding of challenges and factors influencing the use of the systems among their users. HELMS (Higher Education Learning Management System) is a countrywide LMS used for teaching and learning during the quarantine period caused by covid-19 in Afghanistan universities. As it was the first experience of Afghan universities in using the learning management systems during the pandemic, challenges were expected to appear. No previous research has been conducted on either studying the challenges of using the HELMS or investigating the factors influencing the use of HELMS during the Covid-19 pandemic in Afghanistan. Hence, there was no unified view of the potential challenges of using HELMS and factors influencing the use of the HELMS among the researchers. This research aims to investigate the challenges that face the use of HELMS and explore the factors influencing the use of HELMS among both lecturers and students. This study employed a qualitative research method by conducting semi-structured interviews with 100 participants including university management, lecturers, and students. Thematic analysis was used as a method for the analysis of qualitative data. The findings of this research will help policymakers, researchers, and practitioners in public and private universities to grasp knowledge on the successful implementation and use of LMSs during covid-19 and afterward.

The Effect of Garlic and Voluntary Exercise on Cardiac Angiogenesis in Diabetes: The Role of MiR-126 and MiR-210 / O Efeito do Alho e de Exercícios Físicos Voluntários na Angiogênese Cardíaca no Diabetes: O Papel do miRNA-126 e do miRNA-210

Abstract Background: Diabetes mellitus (DM) is one of the major risk factors for cardiovascular disease, leading to endothelial dysfunction and angiogenesis impairment . MiR-126 and miR-210 support angiogenic response in endothelial cells. Objective: The present study sought to explore the effect of garlic and voluntary exercise, alone or together, on miR-126 and miR-210 expressions and cardiac angiogenesis in rats with type 1 diabetes. Methods: Male Wistar rats were divided into five groups (n = 7): Control, Diabetes, Diabetes+Garlic, Diabetes+Exercise, and Diabetes+Garlic+Exercise. Diabetes was induced in the animals by streptozotocin (ip, 50 mg/kg). The rats were then fed raw fresh garlic homogenate (250 mg/kg) or were subjected to voluntary exercise, or to combined garlic and voluntary exercise for 6 weeks. MiR-126 and miR-210 expressions in the myocardium were determined by real time PCR, and the serum lipid profile was measured by enzymatic kits. Angiogenesis was evaluated by immunostaining for PECAM-1/ CD31 in the myocardium. Results: Diabetes reduced both cardiac miR-126 expression and angiogenesis (p < 0.05). On the other hand, there was a miR-210 expression increase in the myocardium of diabetic animals (p < 0.001). However, those effects reversed either with garlic or voluntary exercise (p < 0.01). Moreover, treating diabetic rats with garlic and voluntary exercise combined had an additional effect on the expressions of miR-126 and miR-210 (p < 0.001). Furthermore, both voluntary exercise and garlic significantly improved serum lipid profiles (p < 0.001). Conclusion: The induction of diabetes decreased angiogenesis in the myocardium, whereas our treatment using long-term voluntary exercise and garlic improved myocardial angiogenesis. These changes were possibly owing to the enhancement of myocardial miR-126 and miR-210 expressions.

Resumo Fundamento: O diabetes mellitus (DM) é um dos principais fatores de risco para doenças cardiovasculares, levando à disfunção endotelial e inibição da angiogênese. O miRNA-126 e o miRNA-210 promovem a resposta angiogênica em células endoteliais. Objetivo: O presente estudo buscou explorar o efeito do alho e de exercícios físicos voluntários, isoladamente ou em conjunto, nas expressões do miRNA-126 e do miR-210 e na angiogênese cardíaca em ratos com diabetes tipo 1. Métodos: Ratos Wistar machos foram divididos em cinco grupos (n = 7): Controle, Diabetes, Diabetes+Alho, Diabetes+Exercícios e Diabetes+Alho+Exercícios. Introduziu-se diabetes nos animais por estreptozotocina (ip, 50 mg/kg). Os ratos foram então alimentados com homogenato de alho fresco cru (250 mg/kg), ou foram submetidos a exercícios voluntários, ou a uma combinação de alho e exercícios voluntários, durante 6 semanas. As expressões do miRNA-126 e do miRNA-210 no miocárdio foram determinadas por PCR em tempo real, e o perfil lipídico sérico foi medido por kits enzimáticos. A angiogênese foi avaliada por imunocoloração por PECAM-1/CD31 no miocárdio Resultados: O diabetes reduziu a expressão do miRNA-126 cardíaco e da angiogênese (p < 0,05). Por outro lado, houve um aumento da expressão do miRNA-210 no miocárdio dos animais diabéticos (p < 0,001). No entanto, tais efeitos foram revertidos com alho ou exercícios voluntários (p < 0,01). Além disso, o tratamento de ratos diabéticos conjuntamente com alho e exercícios voluntários teve um efeito adicional sobre as expressões do miRNA-126 e do miRNA-210 (p < 0,001). Além disso, tanto os exercícios voluntários quanto o alho melhoraram significativamente os perfis lipídicos séricos (p < 0,001). Conclusões: A indução de diabetes diminuiu a angiogênese no miocárdio, enquanto nosso tratamento com exercícios voluntários de longa duração e alho melhorou a angiogênese miocárdica. Estas alterações devem-se, possivelmente, ao aumento das expressões do miRNA-126 e do miRNA no miocárdio.

The Effect of Garlic and Voluntary Exercise on Cardiac Angiogenesis in Diabetes: The Role of MiR-126 and MiR-210.

BACKGROUND: Diabetes mellitus (DM) is one of the major risk factors for cardiovascular disease, leading to endothelial dysfunction and angiogenesis impairment . MiR-126 and miR-210 support angiogenic response in endothelial cells. OBJECTIVE: The present study sought to explore the effect of garlic and voluntary exercise, alone or together, on miR-126 and miR-210 expressions and cardiac angiogenesis in rats with type 1 diabetes. METHODS: Male Wistar rats were divided into five groups (n = 7): Control, Diabetes, Diabetes+Garlic, Diabetes+Exercise, and Diabetes+Garlic+Exercise. Diabetes was induced in the animals by streptozotocin (ip, 50 mg/kg). The rats were then fed raw fresh garlic homogenate (250 mg/kg) or were subjected to voluntary exercise, or to combined garlic and voluntary exercise for 6 weeks. MiR-126 and miR-210 expressions in the myocardium were determined by real time PCR, and the serum lipid profile was measured by enzymatic kits. Angiogenesis was evaluated by immunostaining for PECAM-1/ CD31 in the myocardium. RESULTS: Diabetes reduced both cardiac miR-126 expression and angiogenesis (p < 0.05). On the other hand, there was a miR-210 expression increase in the myocardium of diabetic animals (p < 0.001). However, those effects reversed either with garlic or voluntary exercise (p < 0.01). Moreover, treating diabetic rats with garlic and voluntary exercise combined had an additional effect on the expressions of miR-126 and miR-210 (p < 0.001). Furthermore, both voluntary exercise and garlic significantly improved serum lipid profiles (p < 0.001). CONCLUSION: The induction of diabetes decreased angiogenesis in the myocardium, whereas our treatment using long-term voluntary exercise and garlic improved myocardial angiogenesis. These changes were possibly owing to the enhancement of myocardial miR-126 and miR-210 expressions.

Dietary omega-3 and -6 fatty acids affect the expression of prostaglandin E2 synthesis enzymes and receptors in mice uteri during the window of pre-implantation.

Considering possible effects of poly-unsaturated fatty acids (PUFA) on embryo implantation more likely through PGs, we investigated effects of dietary omega-3 and -6 PUFA on prostaglandin E2 (PGE2) signaling in mice uterus during pre-implantation period. The mRNA expressions of microsomal- and cytosolic- PGE synthase (mPGES and cPGES) and protein expressions of PGE receptor 2 and 4 (EP2 and EP4) were evaluated in uterus tissues of control as well as omega 3 and omega 6 received mice at days 1-5 of pregnancy. Expression of cPGES gene was not significantly different between groups but the mPGES expression on days 4 and 5 of pregnancy in supplemented groups was higher than controls. Omega-3 significantly decreased EP2 levels on days 3 and 4, while omega-6 caused an increase on days 3-5 of pregnancy. The levels of EP4 were significantly higher in the omega-6 group than other groups on days 4 and 5 of pregnancy. Also the implantation rate was higher in omega -6 compared to omega-3 group (p = 0.006). Moreover, there were significant correlations between implantation rate with expression levels of mPGES and EP2. Our results showed negative and positive effects of respectively dietary omega-3 and -6 PUFA on PGE2 signaling and implantation rate.

Combination of Vildagliptin and Ischemic Postconditioning in Diabetic Hearts as a Working Strategy to Reduce Myocardial Reperfusion Injury by Restoring Mitochondrial Function and Autophagic Activity.

Purpose: Diabetic hearts are resistant to cardioprotection by ischemic-postconditioning (IPostC). Protection of diabetic hearts and finding related interfering mechanisms would have clinical benefits. This study investigated the combination effects of vildagliptin (Vilda) and IPostC on cardioprotection and the levels of autophagy and mitochondrial function following myocardial ischemia/reperfusion (I/R) injury in type-II diabetic rats. Methods: Diabetes was established by high fat diet/low dose of streptozotocin and lasted for 12 weeks. The diabetic rats received Vilda (6 mg/kg/day, orally) for one month before I/R. Myocardial regional ischemia was induced through the ligation of left coronary artery, and IPostC was applied immediately at the onset of reperfusion. The infarct size was assessed by a computerised planimetry and left ventricles samples were harvested for cardiac mitochondrial function studies (ROS production, membrane potential and staining) and western blotting was used for determination of autophagy markers. Results: None of Vilda or IPostC but combination of them could significantly reduce the infarct size of diabetic hearts, comparing to control (P<0.001). IPostC could not significantly affect p62 expression level in diabetic hearts, but pre-treatment with Vilda alone (p<0.05) and in combination with IPostC (p<0.01) more significantly decreased p62 expression in comparison with corresponding control group. The expression of LC3B-II and LC3BII/LC3BI as well as mitochondrial ROS production were decreased significantly in treatment groups (p<0.001). Mitochondrial membrane depolarization was significantly higher and mitochondrial density was lower in untreated diabetic I/R hearts than treated groups (p<0.001). IPostC in combination with vildagliptin prevented the mitochondrial membrane depolarization and increased the mitochondrial content more potent than IPostC alone in diabetic hearts. Conclusion: Combination of vildagliptin and IPostC in diabetic hearts was a well-working strategy to reduce myocardial I/R damages by restoring mitochondrial membrane potential and ROS production and modulating the autophagic activity in I/R hearts.

Prostaglandin E Pathway in Uterine Tissue During Window of Preimplantation in Female Mice Mated With Intact and Seminal Vesicle-Excised Male.

Prostaglandin E2 (PGE2) has been introduced as an important factor for embryo implantation. So the present study was carried out to evaluate the effect of seminal fluid (SF) on PGE2 pathway in uterus tissues of mice during window of preimplantation. The messenger RNA (mRNA) expressions of microsomal PGE synthase (mPGES) and cytosolic PGE synthase (cPGES) as well as protein expression of PGE receptor 2 and 4 (EP2 and EP4) were determined in uterine tissue of control and seminal vesicle-excised (SVX)-mated female mice during days 1 to 5 of pregnancy using real-time polymerase chain reaction (qRT-PCR) and Western blotting, respectively. We found that mRNA expression of mPGES at day 1 and 2 of pregnancy was significantly higher in the control group than the SVX-mated group ( P < .05), but such result was not obtained for cPGES expression. The protein levels of EP2 at day 1 to 4 of pregnancy were significantly higher in the control group compared with the SVX-mated group ( P < .05), also the EP4 levels were significantly different between the control and SVX-mated groups at the first day of pregnancy ( P < .05). Implantation rate was higher in the control group and also there were positive correlations between mPGES and EP2 expressions in the fifth day of pregnancy with implantation rate. Our results demonstrated significant effect of SF on uterine expressions of the evaluated factors, especially mPGES and EP2. Regarding the correlations between levels of these factors and implantation rate, we suggest that possibly one of the important mechanisms of SF in affecting female pregnancy is through mPGES and EP2.

Combined postconditioning with ischemia and cyclosporine-A restore oxidative stress and histopathological changes in reperfusion injury of diabetic myocardium.

OBJECTIVES: Chronic diabetes impedes cardioprotection in reperfusion injury and hence protecting the diabetic heart would have important outcomes. In this study, we evaluated whether combined postconditioning with ischemia and cyclosporine-A can restore oxidative stress and histopathological changes in reperfusion injury of the diabetic myocardium. MATERIALS AND METHODS: Streptozocin-induced diabetic hearts and nondiabetic controls in eight subgroups (with or without receiving ischemic-postconditioning (IPostC), cyclosporine-A, an inhibitor of mitochondrial permeability transition, or both of them) suffered from 30 min regional ischemia followed by 45 min reperfusion on an isolated-heart Langendorff system. The levels of lactate dehydrogenase (LDH) in the coronary effluent, and the levels of oxidative stress markers including 8-isoprostane, superoxide dismutase (SOD), glutathione peroxidase (GPX), and total antioxidant capacity (TAC) in myocardial supernatant prepared from the ischemic zone were measured using specific kits, spectrophotometrically. Histopathological studies were performed -eosin staining method. RESULTS: Administration of IPostC and cyclosporine-A (alone or together) in nondiabetic hearts potentially reduced the severity of histological changes and level of LDH release as compared with untreated-controls (P<0.05). of any procedures in diabetic hearts did not show significant cardioprotective effects (P>0.1). However, the combined postconditioning with ischemia and CsA exerted significant protective effects in diabetic hearts (P<0.05). CONCLUSION: By augmenting the protective effects of IPostC and CsA through their combined application, reperfusion injury and related oxidative stress are reduced in diabetic hearts similar to non-diabetics.

Impact of high-fat diet and hypoxia on the serum levels of main vasoconstrictors in male rabbits.

Introduction: During atherosclerosis process, vasoconstriction phenomenon occurs which in turn leads to tissue hypoxia. A few studies have been performed on the combination of atherosclerosis and hypoxia as stressors that may accelerate secretion of constrictors. The aim of present study was to evaluate the effects of atherosclerosis and hypoxia on serum levels of main vasoconstrictors (epinephrine, norepinephrine and renin). Methods: In this interventional study, 32 New Zealand white rabbits were randomly divided into four groups (n = 8): normal diet (control group), normal diet exposed to hypoxia (11%, 10 days), high-fat diet (cholesterol-2%, 8 weeks), and high-fat diet with hypoxia. Later, serum levels of renin, epinephrine and norepinephrine were measured on second, 56th and 66th days. Results: High-fat diet and hypoxia caused significant increase in epinephrine and norepinephrine concentrations on days 56 and 66 compared to the control group (P < 0.05). Also, renin showed significance increase in high-fat diet and high-fat diet+ hypoxia groups compared to the control group (P < 0.05). Conclusion: Both high-fat diet and hypoxia increase renin levels in male rabbits. Furthermore, the combination of high-fat diet and hypoxia immensely increases renin levels. Both hypoxia and combined of high-fat diet and hypoxia increase norepinephrine levels. However epinephrine is only increased in the combination of high-fat diet and hypoxia. So the presence of hypoxia in combination with high-fat diet, cause accelerated and aggravated atherosclerosis.

Cardioprotective Effect of Crocin Combined with Voluntary Exercise in Rat: Role of Mir-126 and Mir-210 in Heart Angiogenesis.

BACKGROUND:: Crocin is reported to have a wide range of biological activities such as cardiovascular protection. Recent epidemiologic studies have shown that exercise reduces cardiovascular morbidity and mortality in the general population. OBJECTIVE:: The aim of this study was to evaluate the effect of crocin and voluntary exercise on miR-126 and miR-210 expression levels and angiogenesis in the heart tissue. METHODS:: Animals were divided into 4 groups: control, exercise, crocin, and exercise-crocin. Animals received oral administration of crocin (50 mg/kg) or performed voluntary exercise alone or together for 8 weeks. Akt, ERK1/2 protein levels, miR-126 and miR-210 expression were measured in the heart tissue. Immunohistochemical method was used to detect CD31 in the heart tissue. RESULTS:: Akt and ERK1/2 levels of the heart tissue were higher in crocin treated group and voluntary exercise trained group after 8 weeks. Combination of crocin and exercise also significantly enhanced Akt and ERK1/2 levels in the heart tissue. MiR-126, miR-210 expression and CD31 in the heart increased in both crocin and voluntary exercise groups compared with control group. In addition, combination of exercise and crocin amplified their effect on miR-126 and miR-210 expression, and angiogenesis. CONCLUSION:: Crocin and voluntary exercise improve heart angiogenesis possibly through enhancement of miR-126 and miR-210 expression. Voluntary exercise and diet supplementation with crocin could have beneficial effects in prevention of cardiovascular disease. FUNDAMENTOS:: A crocina tem uma vasta gama de atividades biológicas, tais como a proteção cardiovascular. Estudos epidemiológicos recentes demonstraram que o exercício reduz a morbidade e a mortalidade cardiovasculares na população em geral. OBJETIVO:: O objetivo deste estudo foi avaliar o efeito da crocina e do exercício voluntário nos níveis de expressão miR-126 e miR-210 e na angiogênese no tecido cardíaco. MÉTODOS:: Os animais foram divididos em 4 grupos: controle, exercício, crocina e exercício-crocina. Os animais receberam a administração oral de crocina (50 mg/kg) ou realizaram exercício voluntário sozinhos ou em conjunto durante 8 semanas. Os níveis de proteína Akt, ERK1/2, e a expressão de miR-126 e miR-210 foram medidos no tecido cardíaco. O método imunohistoquímico foi utilizado para detectar CD31 no tecido cardíaco. RESULTADOS:: Os níveis de Akt e ERK1/2 do tecido cardíaco foram maiores no grupo tratado com crocina e no grupo de exercício voluntário após 8 semanas. A combinação de crocina e exercício também aumentou significativamente os níveis de Akt e ERK1/2 no tecido cardíaco. A expressão de MiR-126, miR-210 e CD31 no coração aumentou tanto em no grupo de crocina como no grupo de exercício voluntário em comparação com o grupo de controle. Além disso, a combinação de exercício e crocina amplificou seu efeito na expressão de miR-126 e miR-210 e angiogênese. CONCLUSÃO:: A Crocina e o exercício voluntário melhoram a angiogênese cardíaca possivelmente através do aumento da expressão de miR-126 e miR-210. O exercício voluntário e a suplementação dietética com crocina podem ter efeitos benéficos na prevenção de doenças cardiovasculares.

Cardioprotective Effect of Crocin Combined with Voluntary Exercise in Rat: Role of Mir-126 and Mir-210 in Heart Angiogenesis / Efeito Cardioprotetor de Crocina Combinado com Exercício Voluntário em Ratos: Papel do Mir-126 e Mir-210 na Angiogênese Cardíaca

Abstract Background: Crocin is reported to have a wide range of biological activities such as cardiovascular protection. Recent epidemiologic studies have shown that exercise reduces cardiovascular morbidity and mortality in the general population. Objective: The aim of this study was to evaluate the effect of crocin and voluntary exercise on miR-126 and miR-210 expression levels and angiogenesis in the heart tissue. Methods: Animals were divided into 4 groups: control, exercise, crocin, and exercise-crocin. Animals received oral administration of crocin (50 mg/kg) or performed voluntary exercise alone or together for 8 weeks. Akt, ERK1/2 protein levels, miR-126 and miR-210 expression were measured in the heart tissue. Immunohistochemical method was used to detect CD31 in the heart tissue. Results: Akt and ERK1/2 levels of the heart tissue were higher in crocin treated group and voluntary exercise trained group after 8 weeks. Combination of crocin and exercise also significantly enhanced Akt and ERK1/2 levels in the heart tissue. MiR-126, miR-210 expression and CD31 in the heart increased in both crocin and voluntary exercise groups compared with control group. In addition, combination of exercise and crocin amplified their effect on miR-126 and miR-210 expression, and angiogenesis. Conclusion: Crocin and voluntary exercise improve heart angiogenesis possibly through enhancement of miR-126 and miR-210 expression. Voluntary exercise and diet supplementation with crocin could have beneficial effects in prevention of cardiovascular disease.

Resumo Fundamentos: A crocina tem uma vasta gama de atividades biológicas, tais como a proteção cardiovascular. Estudos epidemiológicos recentes demonstraram que o exercício reduz a morbidade e a mortalidade cardiovasculares na população em geral. Objetivo: O objetivo deste estudo foi avaliar o efeito da crocina e do exercício voluntário nos níveis de expressão miR-126 e miR-210 e na angiogênese no tecido cardíaco. Métodos: Os animais foram divididos em 4 grupos: controle, exercício, crocina e exercício-crocina. Os animais receberam a administração oral de crocina (50 mg/kg) ou realizaram exercício voluntário sozinhos ou em conjunto durante 8 semanas. Os níveis de proteína Akt, ERK1/2, e a expressão de miR-126 e miR-210 foram medidos no tecido cardíaco. O método imunohistoquímico foi utilizado para detectar CD31 no tecido cardíaco. Resultados: Os níveis de Akt e ERK1/2 do tecido cardíaco foram maiores no grupo tratado com crocina e no grupo de exercício voluntário após 8 semanas. A combinação de crocina e exercício também aumentou significativamente os níveis de Akt e ERK1/2 no tecido cardíaco. A expressão de MiR-126, miR-210 e CD31 no coração aumentou tanto em no grupo de crocina como no grupo de exercício voluntário em comparação com o grupo de controle. Além disso, a combinação de exercício e crocina amplificou seu efeito na expressão de miR-126 e miR-210 e angiogênese. Conclusão: A Crocina e o exercício voluntário melhoram a angiogênese cardíaca possivelmente através do aumento da expressão de miR-126 e miR-210. O exercício voluntário e a suplementação dietética com crocina podem ter efeitos benéficos na prevenção de doenças cardiovasculares.

Testosterone and Voluntary Exercise, Alone or Together Increase Cardiac Activation of AKT and ERK1/2 in Diabetic Rats / Testosterona e Exercício Voluntário, Individualmente ou em Conjunto, Aumentam a Ativação Cardíaca de AKT e ERK1/2 em Ratos Diabéticos

Abstract Background: Impaired angiogenesis in cardiac tissue is a major complication of diabetes. Protein kinase B (AKT) and extracellular signal regulated kinase (ERK) signaling pathways play important role during capillary-like network formation in angiogenesis process. Objectives: To determine the effects of testosterone and voluntary exercise on levels of vascularity, phosphorylated Akt (P- AKT) and phosphorylated ERK (P-ERK) in heart tissue of diabetic and castrated diabetic rats. Methods: Type I diabetes was induced by i.p injection of 50 mg/kg of streptozotocin in animals. After 42 days of treatment with testosterone (2mg/kg/day) or voluntary exercise alone or in combination, heart tissue samples were collected and used for histological evaluation and determination of P-AKT and P-ERK levels by ELISA method. Results: Our results showed that either testosterone or exercise increased capillarity, P-AKT, and P-ERK levels in the heart of diabetic rats. Treatment of diabetic rats with testosterone and exercise had a synergistic effect on capillarity, P-AKT, and P-ERK levels in heart. Furthermore, in the castrated diabetes group, capillarity, P-AKT, and P-ERK levels significantly decreased in the heart, whereas either testosterone treatment or exercise training reversed these effects. Also, simultaneous treatment of castrated diabetic rats with testosterone and exercise had an additive effect on P-AKT and P-ERK levels. Conclusion: Our findings suggest that testosterone and exercise alone or together can increase angiogenesis in the heart of diabetic and castrated diabetic rats. The proangiogenesis effects of testosterone and exercise are associated with the enhanced activation of AKT and ERK1/2 in heart tissue.

Resumo Fundamento: Angiogênese prejudicada em tecido cardíaco é uma das principais complicações das diabetes. As vias de sinalização da proteína-quinase B (AKT) e a quinase regulada por sinal extracelular (ERK) exercem um importante papel durante a formação de uma rede similar à capilar no processo de angiogênese. Objetivos: Determinar os efeitos da testosterona e exercícios voluntários sobre os níveis de vascularidade, AKT fosforilada (P- AKT) e ERK fosforilada (P-ERK) sobre o tecido cardíaco de ratos diabéticos e castrados diabéticos. Métodos: A diabetes tipo 1 foi induzida através de injeção intraperitoneal de 50 mg/kg de estreptozotocina em animais. Após 42 dias de tratamento com testosterona (2mg/kg/dia) ou exercícios voluntários, individualmente ou em conjunto, as amostras de tecidos cardíacos foram coletadas e usadas para avaliação histológica e determinação de níveis de P-AKT e P-ERK através do método ELISA. Resultados: Os nossos resultados mostraram que a testosterona ou os exercícios aumentaram a capilaridade, os níveis de P-AKT, e P-ERK nos corações de ratos diabéticos. O tratamento de ratos diabéticos com testosterona e exercícios obteve um efeito sinérgico sobre a capilaridade, níveis de P-AKT, e P-ERK no coração. Além disto, na capilaridade do grupo diabético castrado, os níveis de P-AKT e P-ERK diminuíram significativamente no coração, ao passo que o tratamento com testosterona ou o treinamento com exercícios reverteu tais efeitos. O tratamento simultâneo de ratos diabéticos castrados com testosterona e exercícios obteve um efeito aditivo sobre os níveis de P-AKT e P-ERK. Conclusão: Nossas descobertas sugerem que a testosterona e exercícios, em conjunto ou individualmente, podem aumentar a angiogênese nos corações de ratos diabéticos e castrados diabéticos. Os efeitos favoráveis à angiogênese da testosterona e dos exercícios estão associados à ativação reforçada de AKT e ERK1/2 no tecido cardíaco.

Effect of remote ischemic post-conditioning on oxidative stress in blood of STEMI patients treated with primary angioplasty.

Introduction: This study designed to use remote ischemic post conditioning (RIPC) as a protective strategy during percutaneous coronary intervention (PCI) in patients with ST segment elevation myocardial infarction (STEMI) to reduce myocardial cells damage due to reperfusion injury. Methods: Sixty-one patients were divided into test group (32 patients) receiving RIPC and control group (29 patients). Patients were included with first MI who had 20-80 years old. The RIPC protocol was applied on patients arm in three successive episodes during the opening of infarct-related artery (IRA). Whole blood sample were taken from patients after the first episode before IRA opening and after the third episode after IRA opening. The serums were extracted and stored in the freezer -70˚C to determine the levels of glutathione peroxidase (GPX), superoxide dismutase (SOD), total antioxidant capacity (TAC) and malondialdehyde (MDA). Results: The levels of GPX and SOD after the first episode of RIPC were significantly higher in test group than control group (P < 0.001). Similar alterations of these enzymes were obtained after IRA opening (after third episode). In addition, the levels of TAC remained unchanged in control patients but it was significantly increased after the third episode of RIPC in test patients (P < 0.001). Finally, the MDA level was increased in control group in comparison with test group, and administration of RIPC in test group prevented the enhancement of MDA levels significantly (P < 0.001). Conclusion: The results indicated that RIPC protocol has protective properties in patients with STEMI through enhancing the antioxidant potentials and decreasing lipid peroxidation.

Testosterone and Voluntary Exercise Promote Angiogenesis in Hearts of Rats with Diabetes by Enhancing Expression of VEGF-A and SDF-1a.

OBJECTIVES: Impaired angiogenesis in cardiac tissue is a major complication of diabetes. This study was aimed to evaluate the effects of testosterone and voluntary exercise on vascular endothelial growth factor-A (VEGF-A), stromal cell-derived factor 1a (SDF-1a) and myocardial capillary density in heart of rats with diabetes. METHODS: Type 1 diabetes was induced by intraperitoneal injection of 55 mg/kg of streptozotocin in 80 male Wistar rats. After 42 days of treatment with testosterone (2 mg/kg/day) or voluntary exercise alone or in combination, angiogenesis was determined in the hearts by immunostaining for PECAM-1/CD31. The expressions of VEGF-A and SDF-1a levels in heart were also determined by the ELISA method. RESULTS: Our results showed that capillary density, VEGF-A and SDF-1a levels in the heart were significantly decreased in castrated rats with diabetes, whereas these effects were reversed by testosterone and exercise. Furthermore, simultaneous treatment of castrated rats with diabetes with testosterone and exercise had a synergistic effect on capillary density, VEGF-A and SDF-1a levels in the heart. In the group with diabetes, either testosterone or exercise increased capillary density, VEGF-A and SDF-1a protein levels in heart tissue. However, the effects of combination therapy in rats with diabetes with testosterone and exercise on capillary density, VEGF-A and SDF-1a levels in the heart was synergistic. CONCLUSIONS: Our findings suggest that testosterone and exercise can promote neoangiogenesis in rats with diabetes and in castrated rats with diabetes. The proangiogenesis effect of testosterone and exercise is associated with the enhanced expression of VEGF-A and SDF-1a in heart tissue.

Testosterone and Voluntary Exercise, Alone or Together Increase Cardiac Activation of AKT and ERK1/2 in Diabetic Rats.

BACKGROUND: Impaired angiogenesis in cardiac tissue is a major complication of diabetes. Protein kinase B (AKT) and extracellular signal regulated kinase (ERK) signaling pathways play important role during capillary-like network formation in angiogenesis process. OBJECTIVES: To determine the effects of testosterone and voluntary exercise on levels of vascularity, phosphorylated Akt (P- AKT) and phosphorylated ERK (P-ERK) in heart tissue of diabetic and castrated diabetic rats. METHODS: Type I diabetes was induced by i.p injection of 50 mg/kg of streptozotocin in animals. After 42 days of treatment with testosterone (2mg/kg/day) or voluntary exercise alone or in combination, heart tissue samples were collected and used for histological evaluation and determination of P-AKT and P-ERK levels by ELISA method. RESULTS: Our results showed that either testosterone or exercise increased capillarity, P-AKT, and P-ERK levels in the heart of diabetic rats. Treatment of diabetic rats with testosterone and exercise had a synergistic effect on capillarity, P-AKT, and P-ERK levels in heart. Furthermore, in the castrated diabetes group, capillarity, P-AKT, and P-ERK levels significantly decreased in the heart, whereas either testosterone treatment or exercise training reversed these effects. Also, simultaneous treatment of castrated diabetic rats with testosterone and exercise had an additive effect on P-AKT and P-ERK levels. CONCLUSION: Our findings suggest that testosterone and exercise alone or together can increase angiogenesis in the heart of diabetic and castrated diabetic rats. The proangiogenesis effects of testosterone and exercise are associated with the enhanced activation of AKT and ERK1/2 in heart tissue.

Influence of Two Various Durations of Resistance Exercise on Oxidative Stress in the Male Rat's Hearts.

INTRODUCTION: The previous studies have suggested that alteration in oxidative stress and antioxidant defense depends on various factors, such as mode, intensity, frequency and duration of exercise. In this study, we compared the effects of two various durations of resistance exercise (1 month and 4 month) on oxidative stress and antioxidant status in cardiac tissue. METHODS: Thirty Wistar male rats divided into 3 groups: control (sedentary), exercise-1 (regular exercise for 1 month) and exercise-2 group (regular exercise for 4 months). After the final to the experiment, the rats were anesthetized, and then blood and heart samples were obtained and used to determine glutathione peroxidase (GPX), superoxide dismutase (SOD), malondialdehyde (MDA) and biochemical estimation. RESULTS: MDA levels between control and exercise-2 groups showed no significant difference, hence, MDA level in exercise-1 group was higher compared to control group (P < .01). The heart GPX activity increased significantly in exercise-2 group regarding other groups (P < .01). The SOD activities of groups were similar. Creatine kinase (CK) and lactate dehydrogenase (LDH) concentrations increased in the exercise-1 compared to the other groups (P < .01). CONCLUSION: Our results indicate that in heart, the adaptation and alteration in oxidative stress and cell injury level depend on duration of exercise.

Involvement of Glycogen Synthase Kinase-3ß and Oxidation Status in the Loss of Cardioprotection by Postconditioning in Chronic Diabetic Male Rats.

PURPOSE: Diabetes mellitus as a main risk-factor of ischemic heart disease may interfere with postconditioning'scardioprotective effects. This study aimed to investigate the involvement of glycogen synthase kinase-3ß (GSK-3ß) and oxidation status in chronic diabetes-induced loss of cardioprotective effect of ischemic-postconditioning (IPostC) in Wistar rats. METHODS: After 8 weeks of induction of diabetes by streptozotocin (50mg/kg), hearts of control and diabetic rats were isolated and mounted on a constant-pressure Langendorff system. All hearts were subjected to 30min regional ischemia followed by 60min reperfusion (by occluding and re-opening of left anterior descending coronary artery, respectively). IPostC was applied immediately at the onset of reperfusion. At the end of reperfusion, the infarct size of myocardium was measured via computerized planimetry. Myocardial contents of malondealdehyde and glutathione as indices of oxidative status were assayed spectrophotometrically and the total and phosphorylated forms of myocardial GSK-3ß were quantified through western blotting. RESULTS: IPostC reduced the infarct size of control hearts from 41±2.9% to 28±1.9% (P<0.05), whereas it could not induce significant changes in infarct size of diabetic animals (35±1.8% vs. 39±3.1%). IPostC-induced reduction in malondealdehyde and elevation in glutathione contents were significant only in control not in diabetic hearts. The total forms of GSK-3ß were similar in all groups; however, the phosphorylation of GSK-3ß (at Ser9) by IPostC was greater in control hearts than diabetics (P<0.01). CONCLUSION: The failure of cardioprotection by IPostC in diabetic hearts may be attributed to the loss of phosphorylation of GSK-3ß and thereby increase in oxidative stress in diabetic states.

Phosphorylation of GSK-3ß and reduction of apoptosis as targets of troxerutin effect on reperfusion injury of diabetic myocardium.

Diabetes has various interactions with ischemic heart diseases. Troxerutin, a flavonoid, owns outstanding pharmacological potentials in cardiovascular medicine. The purpose of this study was to investigate the effects of troxerutin on phosphorylation of GSK-3ß protein and apoptosis induced by myocardial ischemia-reperfusion injury in healthy and diabetic hearts. Male Wistar rats (n=36, 250-300 g) were randomly divided into four groups: healthy, diabetic, healthy-troxerutin and diabetic-troxerutin. Diabetes was induced by a single injection of streptozotocin (50 mg/kg; ip) and the diabetic period was lasted for ten weeks. Six weeks after induction of diabetes, troxerutin-treated groups received 150 mg/kg/day troxerutin by oral gavage for 4 weeks. The rats' hearts were transferred to the Langendorff apparatus and then subjected to 30 min regional ischemia followed by 45 min reperfusion. Supernatants of the left ventricle were used to measure the levels of cardiac troponin-I (cTnI) by ELISA, total and phosphorylated form of GSK-3ß by western blotting and tissue apoptosis by TUNEL assay. Troxerutin administration significantly decreased the cTnI levels in healthy and diabetic groups, as compared to the corresponding controls (P<0.05). In addition, troxerutin significantly increased the level of phosphorylated form and the ratio of phosphorylated to total form of GSK-3ß in diabetic and control groups (P<0.05). Tissue apoptosis level and apoptotic index also showed a significant decrease after administration of troxerutin in control and diabetic groups (P<0.05). The findings indicated that the attenuation of GSK-3ß activity and subsequent reduction of apoptosis by troxerutin play significant roles in its cardioprotection on reperfusion injuries.

Voluntary Exercise Protects Heart from Oxidative Stress in Diabetic Rats.

PURPOSE: Oxidative stress plays a key role in the onset and development of diabetes complications. In this study, we evaluated whether voluntary exercise could alleviate oxidative stress in the heart and blood of streptozotocin - induced diabetic rats. METHODS: 28 male Wistar rats were randomly divided into four groups (n=7): control, exercise, diabetes and exercise + diabetes. Diabetes was induced by injection of streptozotocin in male rats. Rats in the trained groups were subjected to voluntary running wheel exercise for 6 weeks. At the end of six weeks blood and heart tissue samples were collected and used for determination of antioxidant enzymes (including SOD, GPX and CAT activities) and MDA level. RESULTS: Exercise significantly reduced MDA levels both in the heart tissue (p<0.01) and blood samples (p<0.05). In addition, exercise significantly increased SOD (p<0.05), GPX (p<0.001) and CAT (p<0.05) in the heart tissue. Voluntary exercise also significantly increased SOD (p<0.01), GPX (p<0.05) and CAT (p<0.001) in the blood. CONCLUSION: Voluntary exercise diminishes the MDA level in blood and heart tissue of diabetic rats. It also accentuates activities of SOD, GPX and CAT. Therefore, it may be considered a useful tool for the reduction of oxidative stress in diabetes.

Beneficial effect of troxerutin on diabetes-induced vascular damages in rat aorta: histopathological alterations and antioxidation mechanism.

BACKGROUND: Diabetes is associated with micro- and macro-vascular complications affecting several organs. Oxidative stress plays a crucial role in the etiology of vascular disease in diabetes. OBJECTIVES: The present study aimed to investigate the beneficial effect of troxerutin on diabetes-induced histopathological damages in rat aorta with focusing on its antioxidative actions. MATERIALS AND METHODS: Male Wistar rats were randomly divided into four groups (n = 8/each): control, control plus troxerutin, diabetic and diabetic plus troxerutin. Diabetes was induced in rats by a single intraperitoneal injection of streptozotocin (50 mg/kg) and lasted for 10 weeks. Troxerutin was administered orally in concentration of 150 mg/kg/daily for one month before killing rats. At the end of treatment period, thoracic aorta was isolated and divided into two parts; one part was immersed in 10% formalin for histopathological evaluations and the other was frozen by liquid nitrogen for assessment of malondialdehyde (MDA, the main product of lipid peroxidation), activity of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPX). RESULTS: Lipid deposition in tunica intimae and media, thickening and structural deformity of vascular tissues as well as the level of plasma glucose and aortic tissue levels of lipid peroxidation were significantly increased in diabetic rats compared to control ones (P < 0.05). Troxerutin significantly reduced the severity of all vascular histopathological damages in treated versus untreated diabetic rats. In addition, treatment of diabetic rats with troxerutin significantly decreased the levels of MDA (5.1 ± 0.3 vs. 9.3 ± 1.2 nmol/mL) (P < 0.01) and increased the activity of antioxidant enzyme GPX compared to untreated-diabetic groups. CONCLUSIONS: Troxerutin may reduce the vascular complications and tissue injuries induced by chronic diabetes in rat aorta through increasing the activity of tissue antioxidant system and reducing the level of lipid peroxidation.

Inhibition of mitochondrial permeability transition pore restores the cardioprotection by postconditioning in diabetic hearts.

BACKGROUND: Cardiovascular risk factors, including diabetes mellitus may attenuate the cardioprotection by postconditioning. This study aimed to investigate the cardioprotective effect of ischemic-postconditioning (IPostC) against ischemia/reperfusion injury in normal and chronically type-1 diabetic rats and the effect of mitochondrial permeability transition pore (mPTP) inhibition in this field. METHODS: Diabetes was induced by a single intra-peritoneal injection of streptozotocin (50 mg/kg) in Wistar male rats (250-300 g). After 8 weeks, the hearts of control and diabetic animals were isolated and mounted on a constant-pressure Langendorff apparatus. All hearts were subjected to 30 min regional ischemia followed by 45 min reperfusion (by occluding and re-opening of LAD coronary artery, respectively). At the end of ischemia, the hearts received IPostC, cyclosporine-A, or both or none of them. Myocardial creatine-kinase (CK) release as an index of tissue injury was measured spectrophotometery in coronary effluent in reperfusion phase. Infarct size was identified by triphenyltetrazolium chloride staining. Heart rate, left ventricular end-diastolic pressure (LVEDP), LV systolic pressure (LVSP), rate-pressure product (RPP) and coronary flow were recorded throughout the experiment. RESULTS: IPostC, applied at the onset of reperfusion, failed to improve myocardial LVEDP and RPP, or reduce tissue damage indicated by infarct size and CK release in diabetic hearts, while it significantly recovered these parameters toward the pre-ischemic values in control hearts (P < 0.05). In contrast, with simultaneous inhibition of mPTP using cyclosporine-A, the cardioprotective effects of IPostC on myocardial hemodynamics, infarct size and CK release were significantly restored in diabetic hearts (P < 0.05). CONCLUSIONS: The loss of cardioprotection by IPostC in diabetic state can be overcome by increasing the potency of protective IPostC through its co-application with mPTP inhibition.