The effectiveness of vitamin C on quinalphos ileal toxicity: a study of histological, ultrastructural, and oxidative stress markers.

There is a significant hazard of human exposure to the organophosphates which is a constant threat, and they are responsible for numerous cases of poisoning and mammalian toxicity annually in non-target wildlife. The antioxidants, including the vitamin C (Vit C), have a protective effect on some organophosphorus compounds-induced organ damage. Quinalphos (QP) is one of these compounds. The investigation's objective is to see if there was any effect of QP on the rat ileum which could be rectified by using Vit C. Three groups of 24 animals were created. As a control, the first group was given pure water. Second group subjected to oral gavages of QPs. Third group rats were given oral gavages of Vit C plus QPs for 10 days. The reaction of ileal enterocytes to food-borne QPs was marked by poorly organized microvilli, numerous vacuoles within them, disrupted nuclei with chromatin margination, disoriented mitochondria, and an expanded intercellular space. The absorptive columnar cell illustrated many vacuoles inside with herniation of microvilli, and normal goblet cells were also seen. Many Paneth cells towards the lumen of intestinal gland contained secretory granules of different sizes and shapes. The histological architecture of the ileal mucosa in the QP plus Vit C group was found to be close to those of healthy controls. The outcomes of this study suggest that administering Vit C in rats treated with QPs protects them from ill dysfunction caused by QP.

The possible effects of α-tocopherol against amiodarone-treated lungs in rats: vimentin detection, lipid peroxidation assay, and histological and ultrastructural evaluations.

The purpose of this study was to learn more about the pathogenesis of amiodarone (AD) on alveoli and also the possible preventive effect of α-tocopherol (α-T) against these hazards. Rats were divided into 4 groups, one of which acted as a control, the second received α-T, the third AD, and the fourth AD and α-T for 2 weeks. Light microscopy (LM), immunohistochemistry, transmission electron microscopy (TEM), and malondialdehyde (MDA) activity were analyzed in sections of lung tissue. Alveoli of lung tissue AD examined with LM showed dilatation of alveolar spaces, aggregation of red blood cells, and narrowing of alveolar septa. When stained with vimentin (VIM), alveoli showed a positive reaction in the majority and a moderate reaction in others. In the pneumocytes of the type II, some cytoplasmic vesicles had been deflated, whereas others contained lamellar bodies, a damaged nucleus, and vesicles in their heterochromatin. In the interstitial space, collagen fibers with aggregation of red blood cells and a disrupted blood-air barrier were detected. In rat lung alveoli treated with AD and α-T, the alveolar septum thickened and the alveolar spaces expanded as estimated. The alveoli of this group had more or less intact type I and II pneumocytes and a better appearance of the blood-air barrier. In the cells of the alveolar lining, the VIM staining leads to a diffuse positive response. Finally, lung parenchyma also improved, suggesting that α-T may help minimize the effects of AD.

Silymarin's defensive role against hepatotoxicity induced by amiodarone in albino rats / El efecto defensivo de silimarin contra la hepatotoxicidad inducida por amiodarona en ratas albinas

SUMMARY: Amiodarone (AMD), an orally powerful antidysrhythmic medication that has caused hepatotoxicity on long-term administration, is commonly used across the world. Silymarin ameliorative effects (SLM); this research elucidated the magnitude of the damage to the liver tissue in AMD. We divided 24 albino rats evenly into four groups given daily doses by gastric tube for eight weeks as follows; the 1st group acted as a control group; the 2nd group received SLM; the 3rd group received AMD; and the 4th group received AMD parallel to SLM. Liver tissues prepared for light, electron microscopic and serum samples screened for biomarkers (I)liver injury enzymes, alanine aminotransferase (ALT) and aspartate aminotransferase (AST); (II) oxidative and antioxidant stress, malondialdehyde (MDA) and superoxide dismutase (SOD); and (III) inflammatory markers, tumor necrosis factor-alpha (TNF-a) and interleukin-6 (IL-6). The findings showed that AMD caused hepatic histological changes that included congestion of the blood vessels, leucocytic infiltration and cytoplasmic vacuolation. Ultrastructural degeneration of the mitochondria, endoplasmic reticulum swelling, nuclear pyknosis and increased fat droplets and lysosomes were observed. The biochemical findings showed an increase in the AMD group's ALT and AST activities. The group of rats treated with AMD and SLM, increased the improvements in histology and ultrastructure, while the ALT and AST levels were reduced. Our findings collectively agreed that SLM has a protective impact on AMD hepatotoxicity which can be due to its antioxidant properties.

RESUMEN: La amiodarona (AMD) es un fuerte medicamento antiarrítmico administrado por vía oral que ha causado hepatotoxicidad en la administración a largo plazo utilizado con frecuencia en todo el mundo. Efectos de mejora de la silimarina (SLM); esta investigación analizó la magnitud del daño al tejido hepático en la DMAE. Dividimos 24 ratas albinas de manera uniforme en cuatro grupos que recibieron dosis diarias por sonda gástrica durante ocho semanas de la siguiente manera; el primer grupo fue designado como grupo control; el segundo grupo recibió SLM; el tercer grupo recibió AMD; y el cuarto grupo recibió AMD en paralelo a SLM. Se prepararon tejidos hepáticos para muestras de suero, microscopía de luz y electrónica y se analizaron para biomarcadores (I) enzimas de daño hepático, alanina aminotransferasa (ALT) y aspartato aminotransferasa (AST); (II) estrés oxidativo y antioxidante, malondialdehído (MDA) y superóxido dismutasa (SOD); y (III) marcadores inflamatorios, factor de necrosis tumoral alfa (TNF-a) e interleucina-6 (IL-6). Los hallazgos mostraron que la DMAE genera cambios histológicos hepáticos que incluyen congestión de los vasos sanguíneos, infiltración leucocítica y vacuolación citoplásmica. Se observó una degeneración ultraestructural de las mitocondrias, aumento del retículo endoplásmico, picnosis nuclear y aumento de gotitas de grasa y lisosomas. Los hallazgos bioquímicos mostraron un aumento en las actividades de ALT y AST del grupo AMD. El grupo de ratas tratadas con AMD y SLM, aumentó las mejoras en histología y ultraestructura, mientras que se redujeron los niveles de ALT y AST. Nuestros hallazgos coincidieron colectivamente en que SLM tiene un impacto protector sobre la hepatotoxicidad de AMD debido a sus propiedades antioxidantes.

Grape seed extract protects against amiodarone - induced nephrotoxicity and ultrastructural alterations associated with the inhibition of biomarkers of inflammation and oxidative stress in rats.

Amiodarone (AMD) is one of the highly effective antiarrhythmic agents used for treating refractory arrhythmias. It is well known to have long-term administration side effects such as nephrotoxicity. The possible ameliorative effects of antioxidant grape seed extract; on the extent of tissue damage in AMD-induced nephrotoxicity has not been investigated before. Twenty-four albino rats were used in this study and divided into four groups (n = 6). The 1st group served as an untreated control group, under the same laboratory conditions, the 2nd group received (100 mg/kg/day) of grape seed extract (GSE), the 3rd group, AMD-treated group, received AMD (40 mg/kg/day) and the 4th group received both AMD and GSE in the same doses as the previous groups. AMD-treated group showed abnormal glomerular capillaries with wrinkling basement membranes damaged mesangial cells and distorted proximal tubules with plenty of lysosomes. Ultrastructural alterations were also observed in this group. This was also associated with a significant increase in biomarkers of kidney injury (creatinine), oxidative stress ((Decreased SOD and increased MDA) and biomarkers of inflammation IL-6) in comparison to the control group. Supplementation of GSE to AMD group for eight weeks counteracted these effects. It caused an improvement in histological and t ultrastructure changes of the renal tissues associated with decreased creatinine and biomarkers of oxidative stress and inflammation in comparison to AMD-treated group. We conclude that GSE protects against AMD-induced kidney injuries in rats, which is associated with the inhibition of biomarkers of inflammation and oxidative stress.

Exendin-4 Protects Against Myocardial Ischemia-Reperfusion Injury by Upregulation of SIRT1 and SIRT3 and Activation of AMPK.

This study evaluated if the cardioprotective effect of Exendin-4 against ischemia/reperfusion (I/R) injury in male rats involves modulation of AMPK and sirtuins. Adult male rats were divided into sham, sham + Exendin-4, I/R, I/R + Exendin-4, and I/R + Exendin-4 + EX-527, a sirt1 inhibitor. Exendin-4 reduced infarct size and preserved the function and structure of the left ventricles (LV) of I/R rats. It also inhibited oxidative stress and apoptosis and upregulated MnSOD and Bcl-2 in their infarcted myocardium. With no effect on SIRTs 2/6/7, Exendin-4 activated and upregulated mRNA and protein levels of SIRT1, increased levels of SIRT3 protein, activated AMPK, and reduced the acetylation of p53 and PGC-1α as well as the phosphorylation of FOXO-1. EX-527 completely abolished all beneficial effects of Exendin-4 in I/R-induced rats. In conclusion, Exendin-4 cardioprotective effect against I/R involves activation of SIRT1 and SIRT3. Graphical Abstract Exendin-4 could scavenge free radical directly, upregulate p53, and through upregulation of SIRT1 and stimulating SIRT1 nuclear accumulation. In addition, Exendin-4 also upregulates SIRT3 which plays an essential role in the upregulation of antioxidants, inhibition of reactive oxygen species (ROS) generation, and prevention of mitochondria damage. Accordingly, SIRT1 induces the deacetylation of PGC-1α and p53 and is able to bind p-FOXO-1. This results in inhibition of cardiomyocyte apoptosis through increasing Bcl-2 levels, activity, and levels of MnSOD; decreasing expression of Bax; decreasing cytochrome C release; and improving mitochondria biogenesis through upregulation of Mfn-2.

Exendin-4 Attenuates Remodeling in the Remote Myocardium of Rats After an Acute Myocardial Infarction by Activating ß-Arrestin-2, Protein Phosphatase 2A, and Glycogen Synthase Kinase-3 and Inhibiting ß-Catenin.

PURPOSE: This study tested if the protective anti-remodeling effect of GLP-1 agonist Exendin-4 after an acute myocardial infarction (MI) in rats involves inhibition of the Wnt1/ß-catenin signaling pathway. METHODS: Rats were divided into sham, sham + Exendin-4 (10 µg/day, i.p), MI, and MI + Exendin-4. MI was introduced to rats by permanent left anterior descending coronary artery (LAD) ligation. RESULTS: On day 7 post-infraction, MI rats showed LV dysfunction with higher serum levels of cardiac markers. Their remote myocardia showed increased mRNA and protein levels of collagen I/III with higher levels of reactive oxygen species (ROS) and inflammatory cytokines, as well as protein levels of Wnt1, phospho-Akt, transforming growth factor (TGF-ß1), Smad, phospho-Smad3, α-SMA, caspase-3, and Bax. They also showed higher protein levels of phospho-glycogen synthase kinase-3ß (p-GSK3ß), as well as total, phosphorylated, and nuclear ß-catenin with a concomitant decrease in the levels of cyclic adenosine monophosphate (cAMP), mRNA of manganese superoxide dismutase (MnSOD), and protein levels of Bcl-2, ß-arrestin-2, and protein phosphatase-2 (PP2A). Administration of Exendin-4 to MI rats reduced the infarct size and reversed the aforementioned signaling molecules without altering protein levels of TGF-1ß and Wnt1 or Akt activation. Interestingly, Exendin-4 increased mRNA levels of MnSOD, protein levels of ß-arrestin-2 and PP2A, and ß-catenin phosphorylation but reduced the phosphorylation of GSK3ß and Smad3, and total ß-catenin levels in the LV of control rats. CONCLUSION: Exendin-4 inhibits the remodeling in the remote myocardium of rats following acute MI by attenuating ß-catenin activation and activating ß-arrestin-2, PP2A, and GSK3ß. Graphical Abstract A graphical abstract that illustrates the mechanisms by which Exendin-4 inhibits cardiac remodeling in remote myocardium of left ventricle MI-induced rats. Mechanisms are assumed to occur in the cardiomyocytes and/or other resident cells such as fibroblast. Β-catenin activation and nuclear translocation are associated with increased synthesis of inflammatory cytokines and transforming growth factor ß-1 (TGF-ß1). GSK3ß is inhibited by phosphorylation at Ser9. Under normal conditions, ß-catenin is degraded in the cytoplasm by the active GSK3ß-dependent degradation complex (un-phosphorylated) which usually phosphorylates ß-catenin at Ser33/37/Thr41. After MI, TGF-ß1, and Wnt 1 levels are significantly increased, the overproduction of Wnt1 induces ß-catenin stabilization and nuclear translocation through increasing the phosphorylation of disheveled (DVL) protein which in turn phosphorylates and inhibits GSK3ß. TGF-ß1 stimulates the phosphorylation of Smad-3 and subsequent nuclear translocation to activate the transcription of collage 1/III and α-smooth muscle actin (α-SMA). Besides, TGF-ß1 stabilizes cytoplasmic ß-catenin levels indirectly by phosphorylation of Akt at Thr308-induced inhibition of GSK3ß by increasing phosphorylation of Ser9. Exendin-4, and possibly through G protein-coupled receptors (GPCRs), increases levels of cAMP and upregulates ß-arrestin-2 levels. Both can result in a positive inotropic effect. Besides, ß-arrestin-2 can stimulate PP2A to dephosphorylation Smad3 (inhibition) and GSK3ß (activation), thus reduces fibrosis and prevents the activation of ß-catenin and collagen deposition.

Antioxidant activity of selenium on bisphenol-induced apoptosis and testicular toxicity of Albino rats / Actividad antioxidante el selenio sobre la apoptosis inducid por bisfenol y toxicidad testicular en ratas albinas

SUMMARY: Bisphenol A (BPA) is an industrial chemical widely used to make polycarbonate plastics for packaging and epoxy resins. This study sought to examine how selenium (Se) affects BPA toxicity in terms of albino rats' histological structure, antioxidant enzymes and reproductive organs (seminiferous tubules). Twenty-four adult male rats were divided into four experimental groups: Group 1: Control; Group 2: Orally administered BPA; Group 3: Orally administered sodium selenite; Group 4: Treated daily with BPA followed by selenium (Se). All experiment done for 4 weeks. BPA exposure caused changes in the testicular histological structure, which consists apoptosis, and led to changes in several biochemical markers: Malondialdehyde, catalase, superoxide dismutase, and glutathione peroxidase. However, these BPA side effects may be ameliorated in rats treated with BPA-plus-Se. These protective effects of Se may attributable to its ability to remove potentially damaging oxidizing agents in living organisms. The results may confirm that Se countered the oxidant effects and increased the BPA-induced stress response in rats. So, Se promotes the healthy growth and development of mammals by protecting them from oxidative stress. As human are greatly exposed to BPA and it can accumulate in tissues, there is concern about human reproductive functions particularly for occupational workers exposed usually to greater levels of BPA. Thus, the use of BPA in multiple industries must be restricted and the inaccurate usage of plastic containers should be avoided to decrease the health hazards. Administration of Se may protect against the adverse effects of BPA on reproductive functions and structures.

RESUMEN: El bisfenol A (BPA) es un químico industrial ampliamente utilizado para fabricar plásticos de policarbonato para envases y resinas epoxi. Este estudio examinó el efecto de selenio (Se) en la toxicidad del BPA en términos de la estructura histológica, enzimas antioxidantes y los órganos reproductivos (túbulos seminíferos) de ratas albinas. Se dividieron veinticuatro ratas macho adultas en cuatro grupos experimentales: Grupo 1: control; Grupo 2: BPA administrado por vía oral; Grupo 3: BPA administrado por vía oral para; Grupo 4: tratado diariamente con BPA seguido de selenio (Se). El experimento se realizó durante cuatro semanas y se observó que la exposición al BPA provocó cambios en la estructura histológica testicular, incluyendo apoptosis, y alteraciones en varios marcadores bioquímicos:malondialdehído, catalasa, superóxido dismutasa y glutatión peroxidasa. Sin embargo, estos efectos secundarios del BPA pueden mejorar en ratas tratadas con BPA-plus-Se. Estos efectos protectores del Se pueden ser atribuidos a la capacidad de eliminar agentes oxidantes potencialmente dañinos en organismos vivos. Los resultados indicaron que se contrarrestaron los efectos oxidantes y aumentó la respuesta al estrés inducido por BPA en ratas, y favorece el crecimiento y desarrollo en los mamíferos al protegerlos del estrés oxidativo. Debido a la exposición al BPA en el ser humano, se puede acumular en los tejidos, por lo que existe una preocupación por el daño a las funciones reproductivas en particular de los trabajadores que generalmente están expuestos a niveles más altos de BPA. Por lo tanto, se debe restringir el uso de BPA en las industrias y evitar el uso incorrecto de envases de plástico para así disminuir los riesgos para la salud. La administración correcta de Se puede proteger contra los efectos adversos del BPA en las funciones y estructuras reproductivas.

Protective effect of dietary vitamin E (alpha; Tocopherol) on artemisinin induced oxidative liver tissue damage in rats / Efecto protector de la vitamina E en la dieta (alfa; tocoferol) sobre el daño oxidativo del tejido hepático inducido por artemisinina en ratas

This experiment was designed to study the effects of oral administration of artemether which is the most rapid-acting class of antimalarial drugs and the possible protective effect of vitamin E taken with it on the liver of albino rats. A total of twenty-four adult male albino rats were used in this study and were divided into four groups. Group one served as a control and rats in group two exposed to oral intake of artemether daily for fifteen days. The third and fourth groups treated with artemether plus low and high doses of vitamin E respectively. At the end of the experiment, the rats were sacrificed, and the livers were obtained and processed for histological, biochemical and statistical studies. Histological study of the hepatocytes of rats exposed to artemether showed nearly complete disintegration of most cellular contents except few numbers of mitochondria and rough endoplasmic reticulum. Also, the cytoplasm of these cells had few lysosomes, many vacuoles and irregular nuclei with abnormal distribution of chromatin and were shown. The hepatic sinusoids were dilated and filled with blood and vacuoles and bile ductules were abnormal in its structure. Treatment with low and high doses of vitamin E in concomitant with artemether ameliorated the hepatic histopathological lesions and its parenchyma attained nearly normal structure. As far as biochemical changes, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in rats treated with artemether were significantly elevated as compared to the control. Superoxide dismutase (SOD) and malondialdehyde (MDA) levels were significantly increased in the liver in rats treated with artemether. However, vitamin E ameliorated the rise in ALT and AST with decreased MDA concentration and levels of SOD as compared to the corresponding artemether group values. Results of the present suggest that artemether has a harmful and stressful effect on hepatic tissue and the treatment with vitamin E may alleviate this toxicity.

Este experimento fue diseñado para estudiar los efectos de la administración oral de arteméter, la clase de medicamentos antipalúdicos de acción rápida, y el posible efecto protector de la vitamina E en el hígado de ratas albinas. Se utilizaron un total de 24 ratas albinas machos adultas y se dividieron en cuatro grupos. El grupo uno sirvió como control y las ratas en el grupo dos recibieron la dosis oral de arteméter diariamente durante 15 días. Los grupos tres y cuatro fueron tratados con arteméter, más dosis bajas y altas de vitamina E, respectivamente. Al final del experimento, se sacrificaron las ratas y se obtuvieron y procesaron los hígados para estudios histológicos, bioquímicos y estadísticos. El estudio histológico de los hepatocitos de ratas expuestas a arteméter mostró una desintegración casi completa de la mayoría de los contenidos celulares, excepto algunos mitocondrias y retículo endoplásmico rugoso. Además, el citoplasma de estas células tenía pocos lisosomas, muchas vacuolas y núcleos irregulares con distribución anormal de cromatina. Los sinusoides hepáticos estaban dilatados y llenos de sangre y vacuolas, y los conductos biliares tenían una estructura anormal. El tratamiento con dosis bajas y altas de vitamina E en forma concomitante con arteméter mejoró las lesiones histopatológicas hepáticas y su parénquima alcanzó una estructura casi normal. En cuanto a los cambios bioquímicos, la alanina aminotransferasa (ALT) y la aspartato aminotransferasa (AST) en ratas tratadas con arteméter se elevaron significativamente en comparación con el control. Los niveles de superóxido dismutasa (SOD) y malondialdehído (MDA) aumentaron significativamente en el hígado en ratas tratadas con arteméter. Sin embargo, la vitamina E mejoró el aumento de ALT y AST con una disminución de la concentración de MDA y los niveles de SOD en comparación con los valores correspondientes del grupo de arteméter. Los resultados del presente estudio sugieren que el arteméter tiene un efecto dañino y estresante sobre el tejido hepático y el tratamiento con vitamina E puede aliviar esta toxicidad.

Ameliorative effect of vitamin E on biochemical and ultrastructural changes in artemether-induced renal toxicity in rats / Efecto paliativo de la vitamina E sobre los cambios bioquímicos y ultraestructurales en la toxicidad renal inducida por arteméter en ratas

This experiment was designed to study the administration of normal doses of one of recent antimalarial drug and coadministration of vitamin E on the kidney tissue. A total twenty-four adult male albino rats were used and divided into four groups: the first one served as a control, the second received artemether orally for three days consecutively. The rats of the third and fourth groups received the same dose of artemether concomitantly with 50 and 100 mg/kg vitamin E orally daily for 2 weeks. After the last dose, the rats were sacrificed and the kidney tissues with blood samples obtained and processed for light, electron microscopic and biochemical analysis. Histologically, artemether treated kidneys showed atrophied glomeruli with widened urinary space and kidney tubules were degenerated with disturbed contour and some vacuoles inside it. Ultrastructurally, the glomeruli of this group showed hypertrophic endothelial cells, irregularity of its basement membrane, disrupted foot processes and filtration slits. The kidney tubule cells showed loss of basal infoldings, cytoplasmic vacuolation, polymorphic damaged swollen mitochondria a loss of its microvilli towards its capillary lumen. Artemether plus vitamin E of the rat kidney groups showed improvement of morphological changes compared to the changes seen in artemether alone. These data were confirmed by biochemical findings with marked improvement of blood urea and creatinine levels and increase of anti-oxidant enzyme activities of glutathione peroxidase and superoxide dismutase in the vitamin E treated groups. The results of this study revealed that vitamins E can improve the adverse changes of artemether of rat renal tissue.

Este proyecto fue diseñado para estudiar la administración de dosis normales de uno de los medicamentos antipalúdicos y de la administración de vitamina E en el tejido renal. Se utilizaron 24 ratas albinas machos adultas divididas en cuatro grupos: el primero sirvió como control, el segundo recibió arteméter por vía oral durante tres días consecutivos. Las ratas del tercer y cuarto grupos recibieron la misma dosis de arteméter concomitantemente con 50 y 100 mg / kg de vitamina E por vía oral diariamente durante 2 semanas. Después de la última dosis, las ratas fueron sacrificadas y se obtuvo el tejido renal de cada muestra los cuales fueron procesados para análisis con microscopías de luz y electrónica, además de exámenes bioquímicos. Histológicamente, los riñones tratados con arteméter mostraron atrofia glomerular con espacio urinario ensanchado y túbulos renales degenerados con contorno alterado y algunas vacuolas en su interior. Ultraestructuralmente, los glomérulos de este grupo mostraron células endoteliales hipertróficas, irregularidad de su membrana basal, procesos alterados del pie y hendiduras de filtración. Las células del túbulo renal mostraron pérdida de inflexiones basales, vacuolación citoplasmática, mitocondrias dañadas y pérdida de sus microvellosidades hacia la luz capilar. Arteméter más vitamina E en los grupos de riñón de rata mostraron una mejora de los cambios morfológicos, en comparación con los cambios observados en arteméter solamente. Estos datos fueron confirmados por hallazgos bioquímicos con una marcada mejoría de los niveles de urea y creatinina en sangre y un aumento de las actividades enzimáticas antioxidantes de la glutatión peroxidasa y la superóxido dismutasa en los grupos tratados con vitamina E. Los resultados de este estudio revelaron que la vitamina E puede mejorar los cambios adversos del arteméter del tejido renal de la rata.

Exendin-4 Ameliorates Cardiac Remodeling in Experimentally Induced Myocardial Infarction in Rats by Inhibiting PARP1/NF-κB Axis in A SIRT1-Dependent Mechanism.

Sirt1 is a potent inhibitor of both poly(ADP-ribose) polymerases1 (PARP1) and NF-kB. This study investigated the cardioprotective effect of exendin-4 on cardiac function and remodeling in rats after an expreimentally-induced myocardial infarction (MI) and explored if this protection involves SIRT1/PARP1 axis. Rats were divided into five groups (n = 10/each): sham, sham + exendin-4 (25 nmol/kg/day i.p.), MI (induced by LAD occlusion), MI + exendin-4, and sham + exendin-4 + EX527 (5 mg/2×/week) (a SIRT1 inhibitor). All treatments were given for 6 weeks post the induction of MI. In sham-operated and MI-induced rats, exendin-4 significantly upregulated Bcl-2 levels, enhanced activity, mRNA, and levels of SIRT1, inhibited activity, mRNA, and levels of PARP1, and reduced ROS generation and PARP1 acetylation. In MI-treated rats, these effects were associated with improved cardiac architectures and LV function, reduced collagen deposition, and reduced mRNA and total levels of TNF-α and IL-6, as well as, the activation of NF-κB p65. In addition, exendin-4 inhibited the interaction of PARP1 with p300, TGF-ß1, Smad3, and NF-κB p65 and signficantly reduced mRNA and protein levels of collagen I/III and protein levels of MMP2/9. In conclusion, exendin-4 is a potent cardioprotective agent that prevents post-MI inflammation and cardiac remodeling by activating SIRT1-induced inhibition of PARP1.

Exendin-4 protects the hearts of rats from ischaemia/reperfusion injury by boosting antioxidant levels and inhibition of JNK/p66 Shc/NADPH axis.

Exendin-4, a glucagon-like peptide-1 receptor agonist, was shown to protect against cardiac ischaemia/reperfusion (I/R) injury by suppressing oxidative stress. p66 Shc, a pro-oxidant and an apoptotic protein, is activated in the infarcted left ventricles (LVs) after induction of I/R. This study investigated if the cardiac protective effect of Exendin-4 against I/R injury in rats involves inhibition of p66 Shc and to determine the underlying mechanisms behind this. Adult male rats (n = 12/group) were divided into four groups as a sham, a sham + Exendin-4, an I/R, and an I/R + Exendin-4. Exendin-4 was administered to rats 7 days before the induction of I/R. Ischaemia was induced by ligating the left anterior descending (LAD) coronary artery for 40 minutes followed by reperfusion for 10 minutes. The infarct myocardium was used for further analysis. Exendin-4 significantly reduced infarct area (by 62%), preserved LV function and lowered serum levels of LDH and CK-MB in I/R-induced rats. Also, it significantly reduced LV levels of ROS and MDA and protein levels of cytochrome-c and cleaved caspase-3 but significantly increased levels of glutathione (GSH) and manganese superoxide dismutase (MnSOD) in LVs of I/R rats indicating antioxidant and anti-apoptotic effects. Furthermore, it inhibited JNK and p66 Shc activation and downregulated protein levels of p66 Shc and NADPH oxidase with no effect on protein levels/activity of p53 and PKCßII. Of note, Exendin-4 also increased GSH and MnSOD in LVs of control rats. In conclusion, Exendin-4 cardioprotective effect in I/R hearts is mediated mainly by antioxidant effect and inhibition of JNK/P66 Shc/NADPH oxidase.

Vitamin C administration attenuated artemether induced hepatic injury in rats / La aAdministración de vitamina C atenúa la lesión hepática inducida por artemeter en ratas

This research was designed to investigate the potential protective effect of vitamin C supplementation against hepatocyte ultrastructural alterations induced by artemether (antimalarial drug) administration. Twenty-four adult male albino rats were used in this study and were divided into four groups (n=6). Group I served as a control and rats in group II administrated artemether (4 mg/kg B.W) orally for three consecutive days. Group III administered artemether plus a low dose of vitamin C (2.86 mg/kg/l water) while group IV received artemether plusa high dose of vitamin C (8.56 mg/kg). At the end of the experimental period (14 days), the harvested liver tissues were examined by transmission electron microscopy (TEM), and blood samples were assayed for biomarkers of liver injury and oxidative stress. Artemether significantly (p<0.05) augmented biomarkers of liver injury such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), and oxidative stress such as superoxide dismutase (SOD), Glutathione Peroxidase (GPX), and caused degeneration and damage of the rough endoplasmic reticulum and disrupted mitochondria. The blood sinusoids were also damaged with distortion of their canaliculi. Administration of vitamin C showed improvement of liver biomarkers, and liver parenchyma, especially in a high dose of vitamin C.We concludes that vitamin C is a partial protective agent against artemether-induced liver injury.

Esta investigación fue diseñada para investigar el posible efecto protector de la vitamina C contra las alteraciones ultraestructurales de los hepatocitos, inducidas por la administración de arteméter (medicamento antipalúdico). En el estudio se utilizaron 24 ratas albinas macho adultas y se dividieron en cuatro grupos (n = 6). El grupo I fue designado como control y las ratas en el grupo II se adminstró Arteméter (4 mg / kg de peso corporal) por vía oral durante tres días consecutivos. En el grupo III se administró arteméter, además de una dosis baja de vitamina C (2,86 mg / kg / l de agua) mientras que el grupo IV recibió arteméter más una dosis alta de vitamina C (8,56 mg / kg). Al final del período experimental (14 días), los tejidos hepáticos recolectados se examinaron por microscopía electrónica de transmisión (MET), y las muestras de sangre se analizaron en busca de biomarcadores de daño hepático y estrés oxidativo. El arteméter aumentó significativamente (p <0,05) los biomarcadores de daño hepático como alanina aminotransferasa (ALT), aspartato aminotransferasa (AST) y estrés oxidativo como superóxido dismutasa (SOD), glutatión peroxidasa (GPX) y causó degeneración y daño de la retículo endoplásmico rugoso y mitocondrias alteradas. Los sinusoides sanguíneos también fueron dañados con la distorsión de sus canalículos. La administración de vitamina C mostró una mejoría de los biomarcadores hepáticos y el parénquima hepático, especialmente en una dosis alta de vitamina C. Concluimos que la vitamina C es un agente protector parcial contra la lesión hepática inducida por arteméter.

Chronic consumption of a high-fat diet rich in corn oil activates intrinsic cell death pathway and induces several ultrastructural changes in the atria of healthy and type 1 diabetic rat.

This study investigates the effect of chronic consumption of a high-fat diet rich in corn oil (CO-HFD) on atrial cells ultrastructure, antioxidant levels and markers of intrinsic cell death of both control and type 1 diabetes mellitus (T1DM)-induced rats. Adult male rats (10 rats/group) were divided into four groups: control fed standard diet (STD) (3.82 kcal/g, 9.4% fat), CO-HFD (5.4 kcal/g, 40% fat), T1DM fed STD, and T1DM + CO-HFD. CO-HFD and T1DM alone or in combination impaired systolic and diastolic functions of rats and significantly reduced levels of GSH and the activity of SOD, enhanced lipid peroxidation, increased protein levels of P53, Bax, cleaved caspase-3, and ANF and decreased levels of Bcl-2 in their atria. Concomitantly, atrial cells exhibited fragmentation of the myofibrils, disorganized mitochondria, decreased number of atrionatriuretic factor (ANF) granules, and loss of gap junctions accompanied by changes in capillary walls. Among all treatments, the severity of all these findings was more severe in T1DM and most profound in the atria of T1DM + CO-HFD. In conclusion, chronic consumption of CO-HFD by T1DM-induced rats elicits significant biochemical and ultrastructural damage to rat atrial cells accompanied by elevated oxidative stress and mitochondria-mediated cell death.

A high-fat diet rich in corn oil induces cardiac fibrosis in rats by activating JAK2/STAT3 and subsequent activation of ANG II/TGF-1ß/Smad3 pathway: The role of ROS and IL-6 trans-signaling.

This study compared the effect of low-fat diet (LFD) and high-fat diet rich in corn oil (HFD-CO) on left ventricular (LV) fibrosis in rats and examined their effect of angiotensin II (ANG II), JAK/STAT, and TGF-1ß/smad3 pathways. As compared to LFD which didn't affect any of the measured parameters, HFD-CO-induced type 2 diabetes phenotype and increased LV collagen synthesis. Mechanistically, it increased LV levels of ROS, ANG II, ACE, IL-6, s-IL-6Rα, TGF-ß1, Smad-3, and activities of JAK1/2 and STAT1/3. AG490, a JAK2 inhibitor, partially ameliorated these effect while Losartan, an AT1 inhibitor completely abolished collagen synthesis. However, with both treatments, levels of ANG II, IL-6, and s-IL-6Rα, and activity of JAK1/STAT3 remained high, all of which were normalized by co-administration of NAC or IL-6 neutralizing antibody. In conclusion: HFD-CO enhances LV collage synthesis by activation of JAK1/STAT3/ANG II/TGF-1ß/smad3 pathway. PRACTICAL APPLICATIONS: We report that chronic consumption of a high-fat diet rich in corn oil (HFD-CO) induces diabetes mellitus phenotype 2 associated with left ventricular (LV) cardiac fibrosis in rats. The findings of this study show that HFD-CO, and through the increasing generation of ROS and IL-6 levels and shedding, could activate LV JAK1/2-STAT1/3  and  renin-angiotensin system (RAS) signaling pathways, thus creating a positive feedback between the two which ultimately leads to activation of TGF-1ß/Smad3 fibrotic pathway. Herein, we also report a beneficial effect of the antioxidant, NAC, or IL-6 neutralizing antibody in preventing such adverse effects of such HFD-CO. However, this presents a warning message to the current sudden increase in idiopathic cardiac disorders, especially with the big shift in our diets toward n-6 PUFA.

Fas/FasL-mediated cell death in rat's diabetic hearts involves activation of calcineurin/NFAT4 and is potentiated by a high-fat diet rich in corn oil.

This study investigated if calcineurin/nuclear factor of activated T cells (NFAT) axis mediates the cardiac apoptosis in rats with type 1 diabetes mellitus (T1DM)-induced rats or administered chronically high-fat diet rich in corn oil (CO-HFD). Also, it investigated the impact of chronic administration of CO-HFD on Fas/Fas ligand (Fas/FasL)-induced apoptosis in the hearts of T1DM-induced rats. Adult male Wistar rats (140-160 g) were classified as control: (10% fat) CO-HFD: (40% fat), T1DM, and T1DM + CO-HFD (n=20/each). In vitro, cardiomyocytes were cultured in either low glucose (LG) or high glucose (HG) media in the presence or absence of linoleic acid (LA) and other inhibitors. Compared to the control, increased reactive oxygen species (ROS), protein levels of cytochrome C, cleaved caspase-8 and caspase-3, myocardial damage and impeded left ventricular (LV) function were observed in the hearts of all treated groups and maximally in T1DM + CO-HFD-treated rats. mRNA of all NFAT members (NFAT1-4) were not affected by any treatment. CO-HFD or LA significantly up-regulated Fas levels in both LVs and cultured cardiomyocytes in a ROS dependent mechanism and independent of modulating intracellular Ca2+ levels or calcineurin activity. T1DM or hyperglycemia significant up-regulated mRNA and protein levels of Fas and FasL by activating Ca2+/calcineurin/NFAT-4 axis. Furthermore, Fas/FasL cell death induced by recombinant FasL (rFasL) or HG media was enhanced by pre-incubating the cells with LA. In conclusion, activation of the Ca2+/calcineurin/NFAT4 axis is indispensable for hyperglycemia-induced Fas/FasL cell death in the cardiomyocytes and CO-HFD sensitizes this by up-regulation of Fas.

Ghrelin prevents cardiac cell apoptosis during cardiac remodelling post experimentally induced myocardial infarction in rats via activation of Raf-MEK1/2-ERK1/2 signalling.

CONTEXT: Mechanisms by which ghrelin affords its cardioprotection in mammals remained unclear. OBJECTIVE: To examine if ghrelin confers cardio-protection during cardiac remodelling post-MI by modulating the RAF-1-MEK1/2-ERK1/2 signalling pathway. MATERIALS AND METHODS: Rats were divided into control, sham, sham + ghrelin, myocardial infarction (MI), and MI + ghrelin groups. Ghrelin (100 µg/kg) was administered for 21 days, starting one-day post-MI. RESULTS: Ghrelin enhanced cardiac contractility and the activities of antioxidant enzymes, lowered serum levels of enzyme markers of cardiac dysfunction, and lowered inflammatory mediator levels. Ghrelin increased levels of phospho-Raf-1 (Ser338), phospho-MEK1/2 (Ser217/221), phospho-ERK1/2 (Thr202/Tyr204), and of their downstream target p-BAD (Ser112) and inhibited the cleavage of caspase-3. Concomitantly, ghrelin prevented the increases in the levels of fibrotic markers, including α-smooth muscle actin (α-SMA), metalloproteinase-9 (MPP-9), and type III collagen. CONCLUSION: Post-MI in rats, ghrelin stimulated Raf-1-MEK1/2-ERK1/2-BAD signalling in the LV infarct areas, accounting for its anti-apoptotic effect, enhancing cardiac function, and inhibiting cardiac fibrosis during cardiac remodelling.

Acylated ghrelin protects aorta damage post-MI via activation of eNOS and inhibition of angiotensin-converting enzyme induced activation of NAD(P)H-dependent oxidase.

NAD(P)H dependent oxidase derived-reactive oxygen species (ROS) due to activation of the renin-angiotensin-aldosterone system (RAAS) in blood vessels postmyocardial infarction MI or during the HF leads to endothelium dysfunction and enhanced apoptosis. Acylated ghrelin (AG) is a well-reported cardioprotective and antiapoptotic agent for the heart. AG receptors are widely distributed in most of blood vessels, suggesting a role in the regulation of endothelial function and survival. This study investigated if AG can protect aorta of rats' postmyocardial infarction (MI)-induced damage and endothelial dysfunction. Adult male rats were divided into four groups of (1) Sham, (2) Sham + AG, (3) MI, and (4) MI + AG. Vehicle (normal saline) or AG (100 µ/kg) was administered to rats for 21 consecutive days, after which, numerous biochemical markers were detected by blot. Both histological and electron microscope studies were carried on aortic samples from MI-induced rats. AG increased protein levels of both total and phosphorylated forms of endothelial nitric oxide synthase (eNOS and p-eNOS, respectively). Only in MI-treated rats, AG prevented the decreases in the levels of reduced glutathione (GSH) and superoxide dismutase (SOD) and lowered levels of malondialdehyde (MDA) and glutathione disulfide (GSSG). Concomitantly, it lowered the increased protein levels of angiotensin-converting enzyme (ACE), p22phox and cleaved caspase-3 and prevented the aorta histological and ultrustructural abnormalities induced by MI.

Ghrelin improves the fine structure of atrial natriuretic factor (ANF) granules and intercalated disc junctions in experimentally-induced myocardial infarction in rats / La grelina mejora las estructuras finas de los gránulos de factor natriurético atrial (ANF) y las uniones intercaladas de disco en el infarto de miocardio inducido experimentalmente en ratas

Ghrelin is a novel growth hormone-releasing peptide administered to treat myocardial infarction (MI). However, the underlying mechanism of its protective effects against MI remains unclear. A total of sixty healthy Sprague Dawley male rats were included. The first one is the sham-operated control group were the rats that underwent the same surgical used to induce MI but without tying the left anterior descending coronary artery (LAD) and received normal saline (0.5 ml) as vehicle; the second MI model group were rats with LAD ligation and received normal saline (0. 5 ml) and the third one is MI+ghrelin group were rats that were exposed to surgery to induce MI but received ghrelin (100 µ/kg, orally, 2x/day). At the end of the experiment after 21 days post-MI, rats were sacrificed and processed for ultrastructural demonstration. Our experiment showed that ghrelin inhibited cardiomyocyte apoptosis. Concomitant administration of ghrelin with MI treated rats of this study appeared to show a considerable protection of the atrial tissues. This study revealed that the sarcoplasm was occupied by normal myofibrils with clear striations and others appeared with minor disruption. Normal distribution of atrionatriuretic factor (ANF) granules and well preserved mitochondrial integrity (preserved cristae, normal size and shape), nucleus chromatin arrangement and striated pattern of clear bands (Z and H) compared to the MI group. Intact intercalated disc with clear identification of fully formed fascia adherence and desmosomes with a reconstruction of gap junction (nexus) was also noticed. Atrial myocytes after myocardial infarction is often associated with subsequent heart failure, which could lead to a fatal outcome. In a rat model of experimental myocardial infarction, peripheral ghrelin administration attenuated myocyte dysfunction, well-preserved desmosome, adherent and gap junction of the intercalated disc and normally distributed ANF granules.

La grelina es un nuevo péptido liberador de hormona de crecimiento administrado para tratar el infarto de miocardio (IM). Sin embargo, el mecanismo subyacente de sus efectos protectores contra el IM aún no se conocen. Se incluyeron un total de 60 ratas macho Sprague Dawley saludables. En el grupo control se incluyeron ratas que fueron sometidas a una cirugía utilizada para inducir el IM, pero sin ligar la arteria coronaria descendente anterior izquierda (ACDAI) y recibieron suero fisiológico normal (0,5 ml) como vehículo; el segundo grupo modelo de IM fueron ratas con ligadura de ACDAI y recibieron suero fisiológico normal (0,5 ml); el tercer grupo estuvo formado por ratas con IM + grelina, expuestas a la cirugía para inducir IM pero luego recibieron grelina (100 m/kg, oralmente, 2x/día). Al final del experimento, 21 días después del infarto de miocardio, los animales fueron sacrificados y procesados para el estudio ultraestructural. Nuestro experimento mostró que la grelina inhibe la apoptosis de los cardiomiocitos. La administración concomitante de grelina en ratas con IM parece indicar una protección considerable de los tejidos atriales. Además, el estudio reveló que el sarcoplasma estaba ocupado por miofibrillas normales con estriaciones claras y otras con una alteración menor. Se encontró una distribución normal de los gránulos del factor natriurético atrial (FNA) e integridad mitocondrial bien conservada (crestas conservadas, tamaño y forma normales), disposición de la cromatina del núcleo y patrón estriado de bandas claras (Z y H) en comparación con el grupo IM. También se observó un disco intercalado intacto con una clara identificación de la adherencia de la fascia completamente formada y desmosomas con una reconstrucción de la unión gap (nexo). Los miocitos atriales, después de un infarto de miocardio, a menudo se asocian con insuficiencia cardíaca posterior, que podría conducir a un desenlace fatal. En un modelo de rata de infarto de miocardio experimental, la administración de grelina periférica atenuó la disfunción de miocitos, con conservación del desmosoma, adherencia y unión de la brecha del disco intercalado y una distribución normal de los los gránulos de FNA.

Subacute ghrelin administration inhibits apoptosis and improves ultrastructural abnormalities in remote myocardium post-myocardial infarction.

This study investigated the effect of ghrelin on cardiomyocytes function, apoptosis and ultra-structural alterations of remote myocardium of the left ventricle (LV) of rats, 21 days post myocardial infarction (MI). Rats were divided into 4 groups as a control, a sham-operated rats, a sham-operated+ghrelin, an MI + vehicle and an MI + ghrelin-treated rats. MI was induced by LAD ligation and then rats were recievd a concomitant doe of either normal saline as a vehicle or treated with ghrelin (100 µg/kg S.C., 2x/day) for 21 consecutive days. Ghrelin enhanced myocardial contractility in control rats and reversed the decreases in myocardial contractility and the increases in the serum levels of CK-MB and LDH in MI-induced rats. Additionally, it inhibited the increases in levels of Bax and cleaved caspase 3 and increased those for Bcl-2 in the remote myocardium of rat's LV, post-MI. At ultra-structural level, while ghrelin has no adverse effects on LV myocardium obtained from control or sham-treated rats, ghrelin post-administration to MI-induced rats reduced vascular formation, restored normal microfilaments appearance and organization, preserved mitochondria structure, and prevented mitochondrial swelling, collagen deposition and number of ghost bodies in the remote areas of their LV. Concomitantly, in remote myocardium of MI-induced rats, ghrelin enhanced endoplasmic reticulum intracellular organelles count, decreased number of atrophied nuclei and phagocytes, diminished the irregularity in the nuclear membranes and inhibited chromatin condensation. In conclusion, in addition to the physiological, biochemical and molecular evidence provided, this is the first study that confirms the anti-apoptotic effect of ghrelin in the remote myocardium of the LV during late MI at the level of ultra-structural changes.

Cardioprotective effect of ghrelin against myocardial infarction-induced left ventricular injury via inhibition of SOCS3 and activation of JAK2/STAT3 signaling.

The molecular mechanisms through which ghrelin exerts its cardioprotective effects during cardiac remodeling post-myocardial infarction (MI) are poorly understood. The aim of this study was to investigate whether the cardioprotection mechanisms are mediated by modulation of JAK/STAT signaling and what triggers this modulation. Rats were divided into six groups (n = 12/group): control, sham, sham + ghrelin (100 µg/kg, s.c., daily, starting 1 day post-MI), MI, MI+ ghrelin, and MI+ ghrelin+ AG490, a potent JAK2 inhibitor (5 mg/kg, i.p., daily). All treatments were administered for 3 weeks. Administration of ghrelin to MI rats improved left ventricle (LV) architecture and restored cardiac contraction. In remote non-infarcted areas of MI rats, ghrelin reduced cardiac inflammation and lipid peroxidation and enhanced antioxidant enzymatic activity. In addition, independent of the growth factor/insulin growth factor-1 (GF/IGF-1) axis, ghrelin significantly increased the phosphorylation of JAK2 and Tyr702 and Ser727 residues of STAT3 and inhibited the phosphorylation of JAK1 and Tyr701 and Ser727 residues of STAT1, simultaneously increasing the expression of BCL-2 and decreasing in the expression of BAX, cleaved CASP3, and FAS. This effect coincided with decreased expression of SOCS3. All these beneficial effects of ghrelin, except its inhibitory action on IL-6 expression, were partially and significantly abolished by the co-administration of AG490. In conclusion, the cardioprotective effect of ghrelin against MI-induced LV injury is exerted via activation of JAK2/STAT3 signaling and inhibition of STAT1 signaling. These effects were independent of the GF/IGF-1 axis and could be partially mediated via inhibition of cardiac IL-6.