apelin-12-peptide and Disease-Models--Animal

Cerebral ischemia is a common neurological disease, and its pathological process remains elusive. This study focused on the protective mechanism of Apelin-12 protein on the nervous system of mice during cerebral ischemia-reperfusion injury through JNK and P38MAPK signaling pathway.. The mouse model with an ischemia-reperfusion injury in middle cerebral artery was prepared by the modified thread-occlusion method and divided into 4 groups randomly. Before implantation of the mice, we assessed the neurological function and evaluated the cerebral edema by the wet-dry weight method. Lactate dehydrogenase (LDH) kit was used to assess the degree of cell injury. Malondialdehyde (MDA) kit was used to measure the level of neuron MDA. Immunohistochemistry was performed to evaluate the neuronal cell in the ischemic brain. Protein expressions of JNK and P38MAPK and apoptosis-related molecules, including Bax, Bcl-2, caspase-3, and cleaved caspase-3, were measured by Western blot assay.. After focal cerebral ischemia-reperfusion, a significant decrease in neurobehavioral score, brain edema and neuron injury in mice occurred. Apelin-12 significantly improved the neurobehavioral score of the mice with ischemia-reperfusion injury, alleviated brain edema and the damage to neurons. In addition, Apelin-12 inhibited the morphological changes and apoptosis of neuronal cells in the ischemic penumbra of mice. Apelin-12 could downregulate the expression of Bax and caspase-3, inhibit the activity of caspase-3 and upregulate the expression of Bcl-2, an anti-apoptotic protein. A significant reduction in the protein expression of p-JNK and p-p38 was observed in the Apelin-12 group compared with that in the I/R or Vehicle group (p<0.05).. When an ischemia-reperfusion injury occurred, Apelin-12 can inhibit the JNK and P38MAPK signaling pathway of the apoptosis-related MAPKs family, thus offering protection to neurons.

Topics: Animals; Brain Ischemia; Disease Models, Animal; Intercellular Signaling Peptides and Proteins; JNK Mitogen-Activated Protein Kinases; Male; MAP Kinase Signaling System; Mice; Neuroprotective Agents; p38 Mitogen-Activated Protein Kinases; Reperfusion Injury

Introduction of isoproterenol (beta-adrenoreceptor agonist) into rats is one of the widespread experimental models of heart failure. It is caused by diffuse ischemic damage of cardiomyocytes, followed by development of substitutive fibrosis. Apelin is a natural regulator of the myocardial contractility. The effects of apelin molecule fragment, apelin-12 and its more stable synthetic analogue, apelin-12-2 on cardiac contractile function of rats with isoproterenol-induced myocardial lesion (IML) and control animals has been studied in this work using invasive (catheterization of the left ventricle) and non-invasive (echocardiography and impedansometry) methods. Infusion of both peptides was made by sequentially increasing rate from 0.5 to 50 µg/kg/min. In the control group, efficacy of apelin-12 was low while apelin-12-2 moderately but significantly increased indices of myocardial contractility and relaxability. These changes were more pronounced in rats with IML and, in addition, the heart rate and LV systolic pressure increased in this group. These results correlate well with echocardiographic studies which showed increases of LV end diastolic volume, stroke volume and ejection fraction by 17-38%. These alterations are probably due to improved Ca2+ transport in cardiomyocytes, as in experiments on isolated cardiomyocytes both apelins have facilitated and improved Ca2+ removal from myoplasma. The results allow to conclude that apelin-12-2 seems to be a promising candidate for further development as a therapeutic agent in heart failure.

Topics: Animals; Disease Models, Animal; Hemodynamics; Intercellular Signaling Peptides and Proteins; Isoproterenol; Male; Myocardial Contraction; Myocardial Infarction; Rats; Rats, Wistar

This study investigated the effects of peptide apelin-12 (H-Arg-Pro-Arg-Leu-Ser-His-Lys-Gly-Pro-Met-Pro-Phe-OH, A12) and its novel structural analog (H-(N(α)Me)Arg-Pro-Arg-Leu-Ser-His-Lys-Gly-Pro-Nle-Pro-Phe-OH, AI) on myocardial antioxidant enzyme activities, lipid peroxidation, and reactive oxygen species formation in ex vivo and in vivo models of myocardial ischemia/reperfusion (I/R) injury. Isolated working rat hearts were subjected to global ischemia and reperfusion. Infusion of 140 μM A12 or AI before global ischemia improved cardiac function recovery; increased the activity of Cu,Zn superoxide dismutase (Cu,Zn SOD), catalase (CAT), and glutathione peroxidase (GSH-Px); decreased malondialdehyde (MDA) content in reperfused heart; and reduced the formation of hydroxyl radical adduct of the spin trap 5,5-dimethyl-1-pyrroline-N-oxide in the myocardial effluent during early reperfusion compared with these indices in control. Anesthetized open-chest rats were subjected to the left anterior descending coronary artery occlusion and coronary reperfusion. Peptide A12 or its analog AI was injected intravenously at the onset of reperfusion at a dose of 0.35 μmol/kg. Treatment with A12 or AI significantly limited infarct size and reduced the activity of lactate dehydrogenase and creatine kinase MB isoenzyme in blood plasma at the end of reperfusion compared with control. These effects were accompanied by complete recovery of Cu,Zn SOD, CAT, and GSH-Px activities; and decrease in MDA content in the area at risk by the end of reperfusion. The study concluded that C-terminal fragment of native peptide apelin-12 and its synthesized analog is involved in the upregulation of cardiac antioxidant defense systems and attenuation of lipid peroxidation in myocardial I/R injury.

Topics: Anesthesia; Animals; Antioxidants; Biomarkers; Catalase; Creatine Kinase, MB Form; Cyclic N-Oxides; Disease Models, Animal; Electron Spin Resonance Spectroscopy; Glutathione Peroxidase; In Vitro Techniques; Intercellular Signaling Peptides and Proteins; L-Lactate Dehydrogenase; Male; Malondialdehyde; Myocardial Reperfusion Injury; Myocardium; Perfusion; Rats, Wistar; Recovery of Function; Superoxide Dismutase

Effects of apelin-12 H-Arg-Pro-Arg-Leu-Ser-His-Lys-Gly-Pro-Met-Pro-Phe-OH (A12) and its modified analogue H-(NMe)Arg-Pro-Arg-Leu-Ser-His-Lys-Gly-Pro-Nle-Pro-Phe-OH (I) on activity of antioxidant enzymes, formation of malonic dialdehyde (MDA) and generation of reactive oxygen species (ROS) were studied in ex vivo and in vivo models of myocardial ischemia and reperfusion (I/R) injury in Wistar rats. Preischemic infusion of peptide A12 or AI enhanced cardiac function recovery of isolated perfused heart and was accompanied by a marked attenuation of ROS generation detected by electron paramagnetic resonance (EPR) technique in myocardial effluent at early reperfusion compared with control. Intravenous administration (i.v.) of peptides in narcotized rats with regional myocardial ischemia limited infarct size and reduced activity of lactate dehydrogenase and MB-fraction of creatine kinase in plasma at the end of reperfusion. Treatment with peptide A12 prevented reduction or augmented activity of myocardial u/Zn superoxide dismutase, catalase and glutathione peroxidase by the end of reperfusion in both I/R models compared with control. Increased MDA content in the area at risk of rat heart in situ at the end of reperfusion was reduced to the initial value under the effect of i.v. A12 administration. Therefore, cardioprotective action of natural apelin-12 and its structural analog AI involve reduction of short-lived ROS generation and improvement of the antioxidant state of ischemic heart during reperfusion.

Topics: Animals; Disease Models, Animal; Intercellular Signaling Peptides and Proteins; Male; Malondialdehyde; Myocardial Ischemia; Myocardial Reperfusion Injury; Myocardium; Oxidative Stress; Rats; Rats, Wistar

Apelin 12 (A-12) was synthesized by the automatic solid phase method with the use of Fmoc technology. The synthesized peptide was purified by preparative HPLC and identified by 1H-NMR spectroscopy and mass spectrometry. Acute myocardial infarction was induced by 40-min LAD occlusion followed by 60-min reperfusion in narcotized Wistar rats. A-12 was administrated at the onset of the reperfusion at doses of 0.07, 0.35 and 0.70 micromole/kg; N(G)-nitro-L-arginine methyl ester (L-NAME), a NOS inhibitor, was applied at a dose of 10 mg/kg 10 min prior to reperfusion alone or before A-12 administration (0.35 micromole/kg); saline was used in control. The indicated A-12 doses induced a transient reduction of the arterial systolic blood pressure (ASBP) to 85, 58, and 56% of the initial level, respectively, which was accompanied by its recovery by the end of reperfusion. All A-12 doses significantly limited myocardial infarct size by 26, 40 and 33%, respectively, compared to the value in control. After administration of A-12 at dose of 0.35 micromol/kg, this effect was combined with reduction of MB-creatine kinase (MB-CK) and lactate dehydrogenase (LDH) activities in plasma at the end of reperfusion by 56 and 47%, respectively, compared to the values in control. Inhibition of NO formation by L-NAME increased SABP but did not affect myocardial infarct size compared with that in control. Coadministration of L-NAME and A-12 resulted in lesser reduction of ASBP during reperfusion than injection of A-12 alone. This intervention led to an increase in infarct size by 26% with concomitant 1.8- and 1.5-times elevation of MB-CK and LDH activities, respectively, compared to the values in the A-12 group. The results indicate that NO is involved as a mediator of the effects of A-12 on the overall protection consisting in a limitation of infarct size and reduction of postischemic cardiomyocyte membrane damage. Cardioprotective mechanisms of apelin action are discussed.

Topics: Animals; Cardiotonic Agents; Disease Models, Animal; Enzyme Inhibitors; Intercellular Signaling Peptides and Proteins; Male; Models, Cardiovascular; Monitoring, Physiologic; Myocardial Contraction; Myocardial Ischemia; Myocardial Reperfusion Injury; Myocytes, Cardiac; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Synthase; Rats; Rats, Wistar; Signal Transduction