Obestatin inhibits apoptosis and astrogliosis of hippocampal neurons following global cerebral ischemia reperfusion via antioxidant and anti-inflammatory mechanisms

Document Type : Original Article


1 Department of Biology, Damghan Branch, Islamic Azad University, Damghan, Iran

2 School of Medicine, Shahroud University of Medical Sciences, Shahroud, Iran


Objective(s): Obestatin is a newly discovered peptide with antioxidant activities in different animal models. Recent studies have shown that Obestatin inhibits apoptosis following cardiac ischemia/reperfusion injury. Brain ischemia/reperfusion induces irreversible damage especially in the hippocampus area. This study aimed at examining the protective impact of Obestatin on apoptosis, protein expression and reactive astrogliosis level in hippocampal CA1 region of rat following transient global cerebral ischemia.
Materials and Methods: Forty-eight male Wistar rats were randomly assigned into 4 groups (sham, ischemia/reperfusion, ischemia/reperfusion+ Obestatin 1, and 5 µg/kg, n=12). Ischemia induced occlusion of both common carotid arteries for 20 min. Obestatin 1 and 5 µg/kg were injected intraperitoneally at the beginning of reperfusion period and 24 and 48 hr after reperfusion. Assessment of the antioxidant enzymes and tumor necrosis factor alpha (TNF-α) was performed by ELISA method. Caspase-3 and glial fibrillary acidic protein (GFAP) proteins expression levels were evaluated by immunohistochemical staining 7 days after ischemia.
Results: Based on the result of the current study, lower superoxide dismutase (SOD) and glutathione (GSH) (P<0.05) and higher malondialdehyde (MDA) and TNF-α levels were observed in the ischemia group than those of the sham group (P<0.01). Obestatin treatment could increase both SOD and GSH (P<0.05) and reduce MDA and TNF-α (P<0.05) versus the ischemia group. Moreover, obestatin could significantly decrease caspase-3 and GFAP positive cells in the CA1 region of hippocampus (P<0.01).
Conclusion: Obestatin exerts protective effects against ischemia injury by inhibition of astrocytes activation and decreases neuronal cell apoptosis via its antioxidant properties.


Main Subjects

1. Li J-B, Asakawa A, Cheng K, Li Y, Chaolu H, Tsai M, et al. Biological effects of obestatin. Endocr 2011;39:205-211.
2. Zhang JV, Ren P-G, Avsian-Kretchmer O, Luo C-W, Rauch R, Klein C, et al. Obestatin, a peptide encoded by the ghrelin gene, opposes ghrelin’s effects on food intake. Science 2005;310:996-999.
3. Pazos Y, Alvarez CJ, Camiña JP, Casanueva FF. Stimulation of extracellular signal-regulated kinases and proliferation in the human gastric cancer cells KATO-III by obestatin. Growth factors 2007; 25:373-384
4. Camiña JP, Campos JF, Caminos JE, Dieguez C, Casanueva FF. Obestatin‐mediated proliferation of human retinal pigment epithelial cells: regulatory mechanisms. J Cell Physiol 2007;211:1-9.
5. Granata R, Settanni F, Gallo D, Trovato L, Biancone L, Cantaluppi V, et al. Obestatin promotes survival of pancreatic β-cells and human islets and induces expression of genes involved in the regulation of β-cell mass and function. Diabetes 2008;57:967-979.
6. Granata R, Volante M, Settanni F, Gauna C, Ghé C, Annunziata M, et al. Unacylated ghrelin and obestatin increase islet cell mass and prevent diabetes in streptozotocin-treated newborn rats. J Mol Endocrinol 2010;45:9-17.
7. Alloatti G, Arnoletti E, Bassino E, Penna C, Perrelli MG, Ghé C, et al. Obestatin affords cardioprotection to the ischemic-reperfused isolated rat heart and inhibits apoptosis in cultures of similarly stressed cardiomyocytes. Am J Physiol Heart Circ Physiol 2010;299: 470-481.
8. Erşahin M, Özsavcı D, Şener A, Özakpınar ÖB, Toklu HZ, Akakin D, et al. Obestatin alleviates subarachnoid haemorrhage-induced oxidative injury in rats via its anti-apoptotic and antioxidant effects. Brain Inj 2013;27:1181-1189.
9. Koyuncuoğlu T, Vızdıklar C, Üren D, Yılmaz H, Yıldırım Ç, Atal SS, et al. Obestatin improves oxidative brain damage and memory dysfunction in rats induced with an epileptic seizure. Peptides 2017;90:37-47.
10.    Flynn R, MacWalter R, Doney A. The cost of cerebral ischaemia. Neuropharmacology 2008;55:250-256.
11.    Tuttolomondo A, Pecoraro R, Arnao V, Maugeri R, Iacopino DG, Pinto A. Developing drug strategies for the neuroprotective treatment of acute ischemic stroke. Expert Rev Neurother  2015;15: 1271-1281.
12.    Kim JY, Park J, Chang JY, Kim S-H, Lee JE. Inflammation after ischemic stroke: the role of leukocytes and glial cells. Exp neurobio 2016;25:241-251.
13.    Cordeau P, Lalancette-Hébert M, Weng YC, Kriz J. Live imaging of neuroinflammation reveals sex and estrogen effects on astrocyte response to ischemic injury. Stroke 2008;39:935-942.
14.    Shamsaei N, Khaksari M, Erfani S, Rajabi H, Aboutaleb N. Exercise preconditioning exhibits neuroprotective effects on hippocampal CA1 neuronal damage after cerebral ischemia. Neural Regen Res 2015;10:1245.
15.    Shafahi M, Vaezi G, Shajiee H, Sharafi S, Khaksari M. Crocin inhibits apoptosis and astrogliosis of hippocampus neurons against methamphetamine neurotoxicity via antioxidant and anti-inflammatory mechanisms. Neurochem Res 2018,43:2252-2259.
16.    Erfani S, Aboutaleb N, Oryan S, Shamsaei N, Khaksari M, Kalalian-Moghaddam H, et al. Visfatin inhibits apoptosis and necrosis of hippocampus CA3 cells following transient global ischemia/reperfusion in rats. Int J Pept Res Ther 2015;21:223-228.
17.    Ghanbari F, Khaksari M, Vaezi G, Hojati V, Shiravi A. Hydrogen sulfide protects hippocampal neurons against methamphetamine neurotoxicity via inhibition of apoptosis and neuroinflammation. J Mol Neurosci 2018:1-9.
18.    Erfani S, Moghimi A, Aboutaleb N, Khaksari M. Nesfatin-1 improve spatial memory impairment following transient global cerebral ischemia/reperfusion via inhibiting microglial and caspase-3 activation. J Mol Neurosci 2018,65:377-384.
19.    Wang C, Liu M, Pan Y, Bai B, Chen J. Global gene expression profile of cerebral ischemia-reperfusion injury in rat MCAO model. Oncotarget 2017;8:74607.
20.    Edwards JL, Vincent AM, Cheng HT, Feldman EL. Diabetic neuropathy: mechanisms to management. Pharmacol Ther 2008;120:1-34.
21.    Rolo AP, Palmeira CM. Diabetes and mitochondrial function: role of hyperglycemia and oxidative stress. Toxicol Appl Pharmacol  2006;212:167-178.
22.    de Zwart LL, Meerman JH, Commandeur JN, Vermeulen NP. Biomarkers of free radical damage: applications in experimental animals and in humans. Free Radic Biol Med 1999,26:202-226.
23.    Warner DS, Sheng H, Batinić-Haberle I. Oxidants, antioxidants and the ischemic brain. J Exp Biol 2004;207:3221-3231.
24.    Hol EM, Pekny M. Glial fibrillary acidic protein (GFAP) and the astrocyte intermediate filament system in diseases of the central nervous system. Curr Opin Cell Biol 2015;32:121-130.
25.    Bélanger M, Allaman I, Magistretti PJ. Brain energy metabolism: focus on astrocyte-neuron metabolic cooperation. Cell Metab 2011;14:724-738.
26.    Lucas SM, Rothwell NJ, Gibson RM. The role of inflammation in CNS injury and disease. Br J Pharmacol 2006;147:125-136.
27.    Burda JE, Sofroniew MV. Reactive gliosis and the multicellular response to CNS damage and disease. Neuron 2014;81:229-248.
28.    Morizawa YM, Hirayama Y, Ohno N, Shibata S, Shigetomi E, Sui Y, et al. Reactive astrocytes function as phagocytes after brain ischemia via ABCA1-mediated pathway. Nat Commun 2017;8:28-36.
29.    Kudabayeva M, Kisel A, Chernysheva G, Smol’yakova V, Plotnikov M, Khodanovich M. The increase in the number of astrocytes in the total cerebral ischemia model in rats. J Phys  2017;21:102-112.
30.    Li M, Li Z, Yao Y, Jin W-N, Wood K, Liu Q, et al. Astrocyte-derived interleukin-15 exacerbates ischemic brain injury via propagation of cellular immunity. Proc Natl Acad Sci 2017;114: 396-405.
31.    Wilms H, Sievers J, Rickert U, Rostami-Yazdi M, Mrowietz U, Lucius R. Dimethylfumarate inhibits microglial and astrocytic inflammation by suppressing the synthesis of nitric oxide, IL-1β, TNF-α and IL-6 in an in-vitro model of brain inflammation. J Neuro Inflamm 2010;7:30-41.
32.    Barone F, Arvin B, White R, Miller A, Webb C, Willette R, et al. Tumor necrosis factor-α: a mediator of focal ischemic brain injury. Stroke 1997;28:1233-1244.
33.    Pamukcu O, Kumral ZNO, Ercan F, Yegen BÇ, Ertem D. Anti-inflammatory effect of obestatin and ghrelin in dextran sulfate sodium–induced colitis in rats. J Pediatr Gastroenterol Nutr 2013;57:211-218.