Nrf-2-dependent antioxidant and anti-inflammatory effects underlie the protective effect of esculeoside A against retinal damage in streptozotocin-induced diabetic rats.

Esculeoside A (ESA) is a tomato-derived glycoside with antioxidant and anti-inflammatory properties. The protective effect of ESA against diabetic retinopathy is not well-investigated and was the core objective of this study. In addition, we tested if such protection involves the activation of Nrf2 signaling. Type 1 diabetes mellitus (T1DM) was induced in adult Wistar male rats by an intraperitoneal injection of streptozotocin (65 mg/kg). Non-diabetic and T1DM rats were divided into two subgroup groups given either the vehicle or ESA (100 mg)/kg. An additional T1DM group was given ESA (100 mg/kg) and an Nrf2 inhibitor (2 mg/kg) (n=8 rats/group). Treatments continued for 12 weeks. In this study, according to the histological features, ESA improved the structure of ganglionic cells and increased the number of cells of the inner nuclear and plexiform layers in the retinas of T1DM rats. Concomitantly, it reduced the retina levels of malondialdehyde (lipid peroxides), vascular endothelial growth factor, interleukin-6, tumor necrosis factor-α, Bax, and caspase-3. In the retinas of the control and diabetic rats, ESA boosted the levels of total glutathione, superoxide dismutase, heme-oxygenase-1, and Bcl2, reduced the mRNA levels of REDD1, and enhanced cytoplasmic and nuclear levels of Nrf2. However, ESA failed to alter the mRNA levels of Nrf2 and keap1, protein levels of keap1, plasma glucose, plasma insulin, serum triglycerides, cholesterol, and LDL-c in both the control and T1DM rats. In conclusion, ESA alleviates retinopathy in T1DM rats by suppressing REDD1-associated degradation and inhibiting the Nrf2/antioxidant axis.

Hyperlipidemia and Hypertension Are Associated With Intracerebral Hemorrhage Incidence: A Retrospective Study.

Introduction Stroke places a huge burden on the socioeconomic systems. Hemorrhagic stroke (HS) is the second most common type of stroke and the second leading cause of disability and death. The updated data on the prevalence of intracerebral hemorrhage (ICH) stroke and related physiological risk factors in Saudi Arabia were limited. The aim of this study was to identify the prevalence of ICH stroke and the related physiological risk factors. Methods This was a retrospective, hospital-based, and chart review study that utilized the BESTCare system at King Abdulaziz Medical City (KAMC), Riyadh, Saudi Arabia. Patients who attended the neurology department (inpatient/outpatient) between 2015 and 2020 were studied. The statistical tool JMP (JMP Inc., Cary, NC, USA) was used for data entry and analysis. Results Patient data (N = 1,870, 58.6 ± 13.87 years old) were screened for comorbidities, hypertension (66.1%), diabetes mellitus (DM) (57.7%), hyperlipidemia (28.4%), and history of an old stroke (22.3%). Ischemic stroke (IS) was more dominant than ICH stroke with ratios of 94.5% (n = 1767) versus 5.5% (n = 103), respectively. The prevalence of ICH stroke among the patients (n = 103) was 10.6%, 20.3%, 24.2%, and 28.1% in the age groups of <40, 41-50, 51-60, and 61-70 years old, respectively. There was a significant gender effect on the distribution of both IS and ICH (p = 0.003). ICH strokes were more prevalent in males than in females. Body mass index (BMI) has no significant effect on the prevalence of IS and ICH stroke (p = 0.081). ICH stroke was significantly associated with DM (p = 0.032), hypertension (p = 0.01), and hyperlipidemia (p = 0.002). Regression analyses show that only hypertension (positive association) and hyperlipidemia (negative association) were significantly associated with the incidence of ICH stroke. Conclusion IS was more prevalent than ICH stroke. ICH strokes were more prevalent in males than in females. Also, hypertension was the most common factor leading to ICH stroke, unlike hyperlipidemia, which was revealed to be protective against ICH stroke.

Resveratrol Modulates Bone Mineral Density and Bone Mineral Content in A Rat Model of Male Hypogonadism.

OBJECTIVE: To determine whether resveratrol (Res) can correct osteoporosis induced in a rat model of male hypogonadism. METHODS: Thirty-two rats were randomly divided into 4 groups, 8 in each group; 1) a control sham group: underwent a similar surgical procedure for induction of orchiectomy (ORCD) without ligation of any arteries or veins or removal of the testis and epididymis; 2) a control + Res-treated group (Con+Res): underwent sham surgery similar to the control, but was then treated with Res, as described below; 3) an ORCD-induced group: bilateral ORCD surgery as described above, and 4) a ORCD+Res-treated group: bilateral ORCD surgery followed by Res treatment. Res treatment began 4 weeks after ORCD and continued for 12 weeks. After 12 weeks, bone mineral density (BMD) and bone mineral content (BMC) were measured in the tibia and femur of each rat's right hind leg. Blood levels of bone turnover indicators such as deoxypyridinoline (Dpd), N-telopeptide of type I collagen (NTX I), alkaline phosphatase (ALP), and osteocalcin (OC), as well as receptor activator of nuclear factor kappa B (RANK) and osteoprotegerin (OPG) were assessed. RESULTS: ORCD significantly decreased BMD (P<0.01) and significantly increased bone resorption, manifested by increased RANK. In addition, it inhibited serum levels of OPG and OC. Res treatment after ORCD effectively increased serum levels of bone formation markers such as OPG and OC, compared with testisectomized rats (P<0.05). CONCLUSION: Res could ameliorate bone loss induced by male hypogonadism, possible via restoration of the normal balance between RANK and OPG.

Ellagic acid protects against non-alcoholic fatty liver disease in streptozotocin-diabetic rats by activating AMPK.

CONTEXT: Ellagic acid (EA) is used in traditional medicine to treated hyperlipidaemia. OBJECTIVE: This study examined if AMPK mediates the anti-steatotic effect of ellagic acid (EA) in streptozotocin (STZ)-induced type 1 diabetes mellitus in rats. MATERIALS AND METHODS: Adult male Wistar rats (130 ± 10 g) were divided into 6 groups (n = 8 rats/group) as control, control + EA, control + EA + CC an AMPK inhibitor), T1DM, T1DM + EA, and T1DM + EA + CC. The treatments with EA (50 mg/kg/orally) and CC (200 ng/rat/i.p.) were given the desired groups for 12 weeks, daily. RESULTS: In T1DM-rats, EA reduced fasting glucose levels (44.8%), increased fasting insulin levels (92.8%), prevented hepatic lipid accumulation, and decreased hepatic and serum levels of total triglycerides (54% & 61%), cholesterol (57% & 48%), and free fatty acids (40% & 37%). It also reduced hepatic levels of ROS (62%), MDA (52%), TNF-α (62%), and IL-6 (57.2%) and the nuclear activity of NF-κB p65 (54%) but increased the nuclear activity of Nrf-2 (4-fold) and levels of GSH (107%) and SOD (87%). Besides, EA reduced downregulated SREBP1 (35%), SREBP2 (34%), ACC-1 (36%), FAS (38%), and HMG-CoAR (49%) but stimulated mRNA levels of PPARα (1.7-fold) and CPT1a (1.8-fold), CPT1b (2.9-fold), and p-AMPK (4-fold). All these events were prevented by the co-administration of CC. DISCUSSION AND CONCLUSIONS: These findings encourage the use of EA to treat hepatic disorders, and non-alcoholic fatty liver disease (NAFLD). Further in vivo and in vitro studies are needed to validate its potential in clinical medicine.

Resolvin D1 prevents cadmium chloride-induced memory loss and hippocampal damage in rats by activation/upregulation of PTEN-induced suppression of PI3K/Akt/mTOR signaling pathway.

This study evaluated the protective effect of resolvin D1 (RVD1) against cadmium chloride (CdCl2 )-induced hippocampal damage and memory loss in rats and investigated if such protection is mediated by modulating the PTEN/PI3K/Akt/mTOR pathway. Adult male Wistar rats (n = 18/group) were divided as control, control + RVD1, CdCl2 , CdCl2  + RVD1 and CdCl2  + RVD1 + bpV(pic), a PTEN inhibitor. All treatments were conducted for 4 weeks. Resolvin D1 improved the memory function as measured by Morris water maze (MWM), preserved the structure of CA1 area of the hippocampus, and increased hippocampal levels of RVD1 in the CdCl2 -treated rats. Resolvin D1 also suppressed the generation of reactive oxygen species (ROS), tumour necrosis factor-α and interleukine-6 (IL-6), inhibited nuclear factor κB (NF-κB) p65, stimulated levels of glutathione (GSH), manganese superoxide dismutase (MnSOD), and Bcl2 but reduced the expression of Bax and cleaved caspase 3 in hippocampi of CdCl2 -treated rats. Concomitantly, it stimulated levels and activity of PTEN and reduced the phosphorylation (activation) of PI3K, Akt and mTOR in hippocampi of CdCl2 -treated rats. In conclusion, RVD1 attenuates CdCl2 -induced memory loss and hippocampal damage in rats mainly by activating PTEN-induced suppression of PI3K/Akt/mTOR, an effect that seems secondary to its' anti-oxidant and anti-inflammatory potential.

Quercetin prevents cadmium chloride-induced hepatic steatosis and fibrosis by downregulating the transcription of miR-21.

This study investigated if cadmium chloride (CdCl2 )-induced hepatic steatosis and fibrosis and the protective effect of quercetin (QUR) are mediated modulating the activity of miR-21, a known hepatic lipogenic and fibrotic miRNA. Male rats (n = 8/group) were divided as control, control + QUR (50 mg/kg; orally), CdCl2 (10 moml/L; drinking water), CdCl2 + miR-21 antagomir (inhibitor) (16 mg/kg/first 3 days), and CdCl2 + QUR (50 mg/kg). Treatments were conducted for 20 weeks, daily. All treatments showed no effect on fasting glucose and insulin levels. Administration of either miR-21 or QUR prevented CdCl2 -induced hepatic damage, as well as lipid droplets and collagen deposition. They also reduced serum levels of ALT and AST and decreased serum and hepatic levels of total cholesterol, triglycerides, and low-density lipoproteins in CdCl2 -treated rats. Concomitantly, they reduced hepatic levels of reactive oxygen species, malondialdehyde, interleukin-6, and tumor necrosis factor-α, suppressed the activation of NF-kb P65, and increased hepatic levels of nuclear factor erythroid 2-related factor 2 (Nrf2), glutathione (GSH), and superoxide dismutase (SOD). These effects were associated with reduced expression of SREBP1, TGF-ß1, Smad3, and collagen1 A and increased expression of PPARα, CPT1, and smad7. Interestingly, QUR significantly lowered levels of miR-21 and increased the protein levels and activity of Nrf2, as well as levels of GSH and SOD in the livers of both the control and CdCl2 -treated rats. Of note, levels of Nrf2 were negatively correlated with the transcription of miR-21. In conclusion: QUR prevents CdCl2 -induced hepatic steatosis and fibrosis mainly through attenuating its ability to upregulate miR-21, at least, by upregulation of Nrf2.

Opposite Modulatory Effects of Crataegus aronia Aqueous Extract on Platelet Aggregation in Rats.

OBJECTIVES: To reveal the mechanisms behind the dual effects of Crataegus aronia (C. aronia) aqueous extract on platelet aggregation by focusing on function, regulation, expression, and signaling of platelets P2Y12 receptors. METHODS: Adult male Wistar rats (120 ± 10 g) were classified as control received the vehicle, C. aronia (200 mg/kg), and C. aronia (2,000 mg/kg)-treated rats. After treatments for consecutive 7 days, hematological and molecular experiments were conducted to detect alterations in platelet aggregation, thromboxane B2 (THXB2) and intracellular reactive oxygen species (ROS) content; protein levels of P2Y12, p-Akt, cyclic adenosine monophosphate (cAMP), phosphorylated vasodilator-stimulated-phosphoprotein (p-VASP), nuclear factor κB (NF-κB), P-selectin, and etc. in platelets were determined by Western blot; mRNA expressions of P2Y12 and some inflammatory markers were determined by real-time polymerase chain reaction. RESULTS: At a concentration of 200 mg/kg, C. aronia inhibited platelet aggregation through multiple interconnected mechanisms including downregulation P2Y12 synthesis and expression, stimulating intracellular cAMP levels and protein levels of p-VASP, inhibiting platelets THXB2 release and protein levels of P-selectin. Also, it inhibited platelets level of ROS and of NF-κB, a major signaling pathway that stimulates the expression of P2Y12 and THXA2 synthesis. Opposite findings were seen in platelets of rats received C. aronia at a concentration of 2,000 mg/kg. Interestingly, co-administration of N-acetylcysteine prevented all hematological and molecular alterations exerted by the high dose of the extract and inhibited platelet aggregation. CONCLUSION: Oral administration of C. aronia at low dose inhibits platelet aggregation by reducing THXB2 release, expression of P-selectin and activating cAMP and Akt signaling through two major mechanisms including downregulation of P2Y12 and inhibition of ROS-induced activation of NF-κB, an effect that is observed to be in the opposite direction with its high dose.

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.

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.

Exposure to cell phones reduces heart rate variability in both normal-weight and obese normotensive medical students.

BACKGROUND: We investigated and compared the effect of the radiofrequency electromagnetic field (RF-EM) emitted by a cell phone on the electrocardiogram and heart rate variability (HRV) of normotensive normal-weight and obese medical students. METHOD: Twenty medical student volunteers, normal weight (age = 23 ± 2, BMI = 23.05 ± 1.72) or obese (age = 24 ± 2, BMI = 32.39 ± 4.78), were exposed to a cell phone (1) close to the heart in silent mode, no ringing or vibrating; (2) close to the heart in ring and vibration mode; (3) next to the ear (brain) while listening; and (4) next to the ear while listening and speaking. RESULTS: The average basal HR of obese students significantly increased, while the PR interval; time domains, including standard deviation (SD) of all normal R-R intervals (SDNN), mean of the SD of all normal R-R intervals (SDNNi), SD of the average of normal R-R intervals (SDANN), and percentage of R-R intervals at least 50 ms different from the previous interval (pNN50); and high-power frequency (HF) decreased. The LF/HF ratio also significantly increased. The SDNN, SDNNi, SDANN, pNN50, and HF levels significantly decreased and the LF/HF significantly increased in normal-weight and obese individuals only when the phone was near the apex of the heart in ring and vibration mode. All changes were more profound in obese students. CONCLUSION: Keeping the phone in a chest pocket reduced the HRV of normal-weight and obese medical students and exaggerated the effect of obesity on sympathetic activation.

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.

Melatonin Improves Memory Deficits in Rats with Cerebral Hypoperfusion, Possibly, Through Decreasing the Expression of Small-Conductance Ca2+-Activated K+ Channels.

This study investigated the expression pattern, regulation of expression, and the role of hippocampal small-conductance Ca2+-activated K+ (SK) channels in memory deficits after cerebral hypoperfusion (CHP) with or without melatonin treatment, in rats. Adults male Wistar rats (n = 20/group) were divided into (1) a sham (2) a sham + melatonin (3) a two-vessel occlusion (2-VO) model, and (4) a 2-VO + melatonin. Melatonin was administered (i.p.) to all rats at a daily dose of 10 mg kg-1 for 7 days starting at the time of 2-VO-induction. In contrast to 2-VO rats, melatonin increased the latency of the passive avoidance learning test and decreased time to find the hidden platform in Water Morris Test in all tested rats. In addition, it concomitantly downregulated SK1, SK2, and SK3 channels, downregulated mRNA levels of TNFα and IL-1ß, enhanced BDNF levels and activity of PKA levels, and restored the levels of cholinergic markers in the hippocampi of the treated-rats. Mechanistically, melatonin significantly prevented CHP-induced activation of ERK1/2, JNK, and P38 MAPK at least by inhibiting ROS generation and enhancing the total antioxidant potential. In cultured hypoxic hippocampal neurons, individual blockage of MAPK signaling by the MEK1/2 inhibitor (U0126), but not by the P38 inhibitor (SB203580) or JNK inhibitor (SP600125), completely prevented the upregulation of all three kinds of SK channels. These data clearly confirm that upregulation of SK channels plays a role in CHP-induced memory loss and indicate that melatonin reverses memory deficits after CHP in rats, at least by, downregulation of SK1, SK2, and SK3 channels in their hippocampi.

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.

Crataegus Aronia protects and reverses vascular inflammation in a high fat diet rat model by an antioxidant mechanism and modulating serum levels of oxidized low-density lipoprotein.

CONTEXT: Crataegus aronia (Willd.) Bosc (Rosaceae) (syn. Azarolus L) is traditionally used to treat cardiovascular disorders. OBJECTIVES: To investigate C. aronia protection against a high-fat diet (HFD)-induced vascular inflammation in rats. MATERIALS AND METHODS: Wistar Male rats (180-220 g) were divided (n = 10/group) as control fed a standard diet (STD), STD + C. aronia (200 mg/kg, orally), HFD, HFD + C. aronia and HFD post-treated with C. aronia. Simvastatin (20 mg/kg) was co- or post-administered as a positive control drug. HFD was given for 8 weeks, and all other treatments were administered for 4 weeks. RESULTS: Most significantly, co-administration of C. aronia to HFD-fed rats reduced the thickness of aorta tunica media (90 ± 5 vs. 160 ± 11.3 µm) and adventitia (54.3 ± 3.8 vs. 93.6 ± 9.4 µm). It also lowered protein levels of TNF-α (0.51 ± 0.15 and 0.15 ± 0.16 vs. 0.1 ± 0.09%) and IL-6 (0.52 ± 0.19 vs. 1.0 ± 0.2%) in their aorta or serum (5.9 ± 0.91 vs. 12.98 ± 1.3 ng/mL and 78.1 ± 6.7 vs. 439 ± 78 pg/mL, respectively). It also lowered all serum lipids and increased aorta levels of GSH levels (70.4 ± 4.0 vs. 40.7 µM) and activity of SOD (5.7 ± 0.7 vs. 2.9 ± 0.6 U/mg) and decreased serum levels of ox-LDL-c (566.7 ± 46 vs. 1817 ± 147 ng/mL). Such effects were more profound than all other treatments. CONCLUSIONS: C. aronia inhibits the HFD-induced vascular inflammation and its use in clinical trials is recommended.

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.

Possible mechanisms underlying fatty liver in a rat model of male hypogonadism: A protective role for testosterone.

AIMS: To investigate the effects of testosterone (Test) deficiency and testosterone replacement therapy (TRT) on the development of non-alcoholic fatty liver disease (NAFLD) and associated peripheral insulin resistance (IR) in male rats and to illustrate the underlying mechanisms of action. MATERIALS AND METHODS: male Sprague Dawley rats were divided into 3 groups as follows: 1) sham-operated group (n = 11), 2) ORCD-induced group (n = 9) exposed to orchidectomy (ORCD), achieved by complete surgical removal of testicles, and 3) ORCD + Test treated group (n = 10) (11 ng/mL Test propionate, 3x/week, S.C.). RESULTS: Data revealed significant increases in final body, liver, visceral and subcutaneous fats weights with significant increases in fasting plasma glucose and insulin levels and HOMA-IR. Additionally, ORCD rats had higher UAC for measured glucose levels and insulin levels during OGTT and higher AUC for measured glucose levels during ITT. Interesting, higher serum and hepatic levels of TGs and CHOL and higher serum levels of LDL were seen in ORCD-induced rats. Mechanistically, significant increases in mRNA levels of SREBP-1, SREBP-2, ACC-1, FAS, HMGCOAR and HMGCOAS with significant increases in protein levels of both precursor and mature SREBP-1 and SREBP-2, PPAR-α, p-PPAR-α, CPT-1 and UCP-2 and significant lower protein levels p-AMPK and p-ACC-1 were detected in livers of ORCD rats. Test administration to ORCD-induced rats significantly ameliorated all of the above mentioned biochemical endpoints and reversed the effect of ORCD on mRNA and protein levels of these targets. In conclusion, Test deficiency could be an independent risk factor for the development of NAFLD by upregulation of lipid synthesis and disturb fatty acids oxidation whereas Test therapy is a protective strategy.