apelin-13-peptide and Reperfusion-Injury

Topics: Animals; Autophagy; Endothelial Cells; Glucose; Mice; Oxygen; Proto-Oncogene Proteins c-akt; Reperfusion; Reperfusion Injury; Signal Transduction; TOR Serine-Threonine Kinases

The precise mechanisms whereby apelin-13 acts against ischemic stroke have remained in the dark. Hence, this study aims to examine the effects of apelin-13 on hypothalamic-pituitary-adrenal (HPA) axis over activation, Jak2-STAT3 signaling pathway, and inflammation following ischemic stroke.. Middle cerebral artery occlusion (MCAO) was used to induce the cerebral ischemic/reperfusion injury (I/RI). Thirty-five male Wistar rats (250-300 g, 8 weeks old) were randomly divided into sham, MCAO, and intravenous (IV) apelin-13 treated groups which received 10, 20, and 40 µg/kg 5 min before reperfusion (n = 7). Neurological status (modified Longa scoring scale), infarct volume, serum levels of malondialdehyde (MDA), total antioxidant capacity (TAC), interleukin 6 (IL-6), corticosterone, and the expressions of the Jak2/STAT3 were assessed.. Our results confirm that IV administration of all three doses of apelin-13 significantly improved neurological defects and reduced infarct volume following cerebral I/RI. Furthermore, we observed that acute stroke caused a rise in the expression of the Jak2/STAT3, IL-6, corticosterone, and MDA content, while apelin-13 could reduce the expression of the Jak2/STAT3 and the serum indices in a dose-dependent manner. The 40 µg/kg dose of apelin-13 was also more effective in reducing the infarct volume and improving TAC.. Our findings suggest that apelin-13 has protective effects against cerebral I/RI-related inflammation and also could attenuate the HPA axis over activation.

Topics: Animals; Brain Ischemia; Corticosterone; Hypothalamo-Hypophyseal System; Infarction, Middle Cerebral Artery; Inflammation; Interleukin-6; Ischemic Stroke; Janus Kinase 2; Male; Pituitary-Adrenal System; Rats; Rats, Wistar; Reperfusion Injury; Signal Transduction

Apelin has been reported to regulate mitochondrial function in myocardial ischemia-reperfusion injury and cerebral ischemia-reperfusion injury. However, the role of apelin-13 in lung ischemia-reperfusion injury (LIRI) remains unclear. This study established an experimental rat model to evaluate the underlying mechanisms of apelin-13 on LIRI. Twenty-four rats were randomly divided to sham operation group (group SM), ischemia/reperfusion group (group IR), and apelin-13 treatment group (group APL). The effects of apelin-13 on LIRI were determined histologically using H&E staining, while the wet/dry weight ratio was used to assess lung edema caused by LIRI. Inflammatory cytokines were also detected in Bronchoalveolar lavage (BAL) fluid by ELISA. The protein expression of UCP2 and the morphological changes of mitochondria were determined by western blotting and electromicroscopy, respectively. The results demonstrated the structural damage of lung tissues and lung edema in group IR. An increased level of inflammatory cytokines including IL-1β, IL-6 and TNF-α was observed in rats with LIRI using ELISA. After that, oxidative stress and morphological damage of mitochondria were also shown in group IR. Yet, the application of apelin-13 reversed all these deleterious effects in group APL. The protective effects of apelin-13 were indicated by decreased reactive oxygen species (ROS) and elevated UCP2 expression levels in rats. In conclusion, this study revealed that apelin-13 had protective effects against LIRI via attenuating lung edema, the production of inflammatory cytokines, oxidative stress and mitochondrial dysfunction.

Topics: Animals; Anti-Inflammatory Agents; Bronchoalveolar Lavage Fluid; Cytokines; Intercellular Signaling Peptides and Proteins; Lung; Male; Malondialdehyde; Mitochondria; Oxidative Stress; Protective Agents; Rats, Sprague-Dawley; Reperfusion Injury; Superoxide Dismutase; Uncoupling Protein 2

It has been reported that apelin-13 possesses neuroprotective effects against cerebral ischemia/reperfusion injury (IRI). Disabilities in sense, movement and balance are the major stroke complications which, result in a high rate of mortality. Here, effects of intravenous (IV) injection of apelin-13 on the severity of neural death, infarct volume, neurological defects and its association with nitric oxide (NO) were investigated. A rat model of cerebral IRI was created by middle cerebral artery occlusion (MCAO) for 60 min and restoration of blood flow for 23 h. Animals were randomly assigned into six groups: sham, ischemia (MCAO), vehicle (MCAO + PBS) and three treatment groups (MCAO + apelin-13 in 10, 20, 40 μg/kg doses, IV). All injections were carried out via tail vein injection 5 min before reperfusion. Neural loss and infarct volume were evaluated by Nissl and 2,3,5-triphenyltetrazolium chloride (TTC) staining, respectively. Neurological defects were scored by standard modified criteria. Serum NO was measured by colorimetric method. Apelin-13 in doses of 20 and 40 μg/kg significantly reduced neural death, infarct volume and disturbance of sensory-motor balance compared to control and vehicle groups (p < 0.05). Serum NO levels reduced in MCAO groups compared to sham. Apelin-13 restored serum NO levels at 20 μg/kg dose (p < 0.05). Our data showed beneficial effect of IV injection of apelin-13 on sensory-motor balance defects by reducing neural death and restoration of serum NO levels. The present study shows the validity of apelin-13 in treatment of ischemic stroke in different administration methods.

Topics: Animals; Disease Models, Animal; Infarction, Middle Cerebral Artery; Injections, Intravenous; Intercellular Signaling Peptides and Proteins; Male; Motor Skills; Neuroprotective Agents; Nitric Oxide; Rats; Rats, Wistar; Reperfusion Injury

Topics: Animals; Cytoprotection; Dinoprostone; Dose-Response Relationship, Drug; Intercellular Signaling Peptides and Proteins; Male; Nitric Oxide; Peroxidase; Rats; Rats, Wistar; Receptor, Cholecystokinin B; Reperfusion Injury; Sensory Receptor Cells; Stomach; Vagus Nerve

This study aimed to explore the effect of Apelin-13 in protecting rats against spinal cord ischemia reperfusion injury (SCIR), as well as the related molecular mechanisms.. One week prior to the experiment, experimental Sprague-Dawley rats were injected with Apelin-13 and the autophagy activator rapamycin through the tail vein once a day for 7 consecutive days. The SCIR rat model was prepared through the abdominal aorta clamping method. At 72 h after injury, the spinal cord tissue water content, infarct volume, and normal neuron count were determined to evaluate the degree of spinal cord tissue injury in the rats. The Basso-Beattie-Bresnahan scoring standard was adopted for functional scoring of the rat hind leg, to reflect the post-injury motor function. At 72 h after injury, changes in mitochondrial membrane potential, reactive oxygen species content, and mitochondrial ATP were detected. ELISA was carried out to detect the malonaldehyde content, as well as catalase, superoxide dismutase, and glutathione catalase activities in spinal cord tissues at 72 h after injury. Quantitative chemistry was conducted to examine the contents of nitric oxide (NO) and endothelial nitric oxide synthase (eNOS) in spinal cord tissues. Finally, the expression of autophagy-related proteins, Beclin1, ATG5, and LC3, in spinal cord tissues was detected through the Western blotting assay.. Apelin-13 pretreatment alleviated SCIR, promoted motor function recovery, suppressed mitochondrial dysfunction, resisted oxidative stress, and inhibited autophagy in spinal cord tissues following ischemia reperfusion injury.. Apelin-3 exerts protection against SCIR by suppressing autophagy.

Topics: Animals; Autophagy; Disease Models, Animal; Dose-Response Relationship, Drug; Injections, Intravenous; Intercellular Signaling Peptides and Proteins; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Spinal Cord Ischemia; Structure-Activity Relationship

Topics: Apelin; Epidermal Growth Factor; Humans; Intercellular Signaling Peptides and Proteins; Reperfusion Injury; Signal Transduction

Apelin is a peptide hormone defined as a ligand for G-protein clamped receptor (APJ) receptor. It is indicated in the literature both apelin and APJ are synthesized on the peripheral tissues including the renal tissues. Which roles does the apelin play on the renal tissue has not been completely illuminated yet. This study is designed to determine the possible protective effect of apelin-13 on the kidney I/R injury. Adult male Sprague-Dawley rats were used in this study. In the sham group, right kidneys of the animals were dissected. In the I/R group, right kidney was dissected and ischemia of 45 min was performed, and then reperfusion was applied for 3 h. In the treatment groups, three different doses of apelin were injected at the beginning of the ischemia unlike the I/R group. BUN, Cre, Na, K, Cl, total protein and albumin from serum samples were determined and TNF-α, IL-1β, IL-6, TAS and TOS parameters were read with ELISA reader. MDA, SOD, CAT and GSH-Px enzyme activations from renal tissues were measured. In comparison with the sham and I/R groups, while the serum BUN, CRE, CI and TNF-α levels showed an increase in the groups on which the apelin-13 was applied, Na, total protein, albumin, TAS levels decreased. Serum TOS level of other groups showed an increase by comparison with the sham group. Our results showed that apelin-13 applied after I/R increased the antioxidant enzyme activity in a dose dependent manner, prevented the lipid oxidation and improved the renal functions.

Topics: Acute Kidney Injury; Animals; Antioxidants; Apelin Receptors; Disease Models, Animal; Humans; Intercellular Signaling Peptides and Proteins; Kidney; Kidney Function Tests; Male; Oxidative Stress; Rats; Rats, Sprague-Dawley; Receptors, G-Protein-Coupled; Reperfusion Injury

Renal ischemia/reperfusion (I/R) injury is the most common cause of acute kidney injury, having a high rate of mortality and no effective therapy currently available. Apelin-13, a bioactive peptide, has been shown to inhibit the early lesions of diabetic nephropathy in several mouse models by us and others. To test whether apelin-13 protects against renal I/R induced injury, male rats were exposed to renal I/R injury with or without apelin-13 treatment for 3 days. Apelin-13 treatment markedly reduced the injury-induced tubular lesions, renal cell apoptosis, and normalized the injury induced renal dysfunction. Apelin-13 treatment inhibited the injury-induced elevation of inflammatory factors and Tgf-β1, as well as apoptosis. Apelin-13 treatment also inhibited the injury-induced elevation of histone methylation and Kmt2d, a histone methyltransferase of H3K4me2, following renal I/R injury. Furthermore, in cultured renal mesangial and tubular cells, apelin-13 suppressed the injury-induced elevation of Tgf-β1, apoptosis, H3K4me2 and Kmt2d under the in vitro hypoxia/reperfusion (H/R) conditions. Consistently, over-expression of apelin significantly inhibited H/R-induced elevation of TGF-β1, apoptosis, H3K4me2 and Kmt2d. The present study therefore suggests apelin-13 may be a therapeutic candidate for treating acute kidney injury.

Topics: Animals; Apoptosis; Cell Line; Histones; Intercellular Signaling Peptides and Proteins; Kidney; Male; Rats; Rats, Wistar; Reperfusion Injury; Transforming Growth Factor beta1

To investigate the protective effect of Apelin-13 on focal cerebral ischemia-reperfusion injury in rats.. Focal transient cerebral ischemia-reperfusion injury was induced in male SD rats using modified suture occlusion technique. The rats were randomly divided into 5 groups: Sham group, Model group, Apelin-low dose (A) group, Apelin-middle dose (B) group and Apelin-high dose (C) group. Apelin-13 was injected into lateral cerebral ventricle, and the neurological function score, brain edema, infarct volume, apoptosis, malondialdehyde (MDA), superoxide dismutase (SOD) and extracellular regulated kinase1/2 (ERK1/2) protein were measured.. Neurological function scores, percentage of brain water content, infarct volumes and TUNEL-positive cells in B and C groups were lower than those in Model group (P<0.05). The level of MDA in the tissue bomogenate of brain tissue in the surrounding area of ischemia of B and C groups was lower than that of Model group, while the activity of SOD was higher (P<0.05). There was no significant difference in ERK1/2 protein expression among the groups (P>0.05). P-ERK1/2 increased in Model group and A, B, and C groups compared with Sham group (P<0.05), and that of A, B, and C group was higher than that of Model group (P<0.05).. Apelin-13 may play an important role by inhibiting oxidative stress to protect against focal cerebral ischemia-reperfusion injury; ERK1/2 signaling pathway may be involved in the protective mechanism of Apelin-13.

Topics: Animals; Apoptosis; Brain Edema; Brain Ischemia; Intercellular Signaling Peptides and Proteins; Male; Malondialdehyde; Oxidative Stress; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Signal Transduction; Superoxide Dismutase

Apelin has been proved to protect the heart against ischemia/reperfusion (I/R) injury via the activation of phosphatidylinositol 3-kinase (PI3K)/Akt and extracellular signal-regulated kinase (ERK) signaling pathways. Whether this protective effect applies to brain I/R injury needed to be explored. We therefore investigated the potential neuroprotective role of Apelin-13 and the underlying mechanisms. Focal transient cerebral I/R model in male ICR mice was induced by 60min of ischemia followed by reperfusion. Apelin-13 intracerebroventricular injection was performed 15 min before reperfusion. Neurological function, infarct volume, brain edema and apoptosis were measured at 24h after stroke. To further test the mechanism of Apelin-13, PI3K inhibitor LY294002 and ERK1/2 inhibitor PD98059 were injected into the lateral cerebral ventricle 15min before ischemia. Compared with the Vehicle group, Apelin-13 significantly ameliorated neurological deficit, infarct volume, brain edema and reduced TUNEL-positive cells. Bax, caspase-3 and cleaved caspase-3 were down-regulated and Bcl-2 up-regulated. While, the effect of Apelin-13 on Bax, Bcl-2, caspase-3 and cleaved caspase-3 was attenuated by LY294002 and PD98059. Apelin protected the brain against I/R insult injury, and this effect may be through activation of PI3K/Akt and ERK1/2 signaling pathways.

Topics: Animals; Apoptosis; Brain; Brain Edema; Brain Infarction; Brain Ischemia; Caspase 3; Chromones; Enzyme Activation; Flavonoids; Gene Expression Regulation; Intercellular Signaling Peptides and Proteins; Male; Mice, Inbred ICR; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Morpholines; Neuroprotective Agents; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; Reperfusion Injury; Signal Transduction