title: Downstream modulation of extrinsic apoptotic pathway in streptozotocin-induced Alzheimer's dementia in rats: Erythropoietin versus curcumin.
abstract: Erythropoietin and curcumin showed promising neuroprotective effects in various models of Alzheimer's dementia. This study was designed to compare the beneficial effects of erythropoietin and/or curcumin in intracerebro-ventricular (ICV) streptozotocin-induced Alzheimer's like disease in rats. Rats received ICV injection of either saline (control, n=8 rats), or streptozotocin. Three weeks following surgery, streptozotocin-injected rats were assigned into 4 groups (8 rats each); vehicle, curcumin (80mg/kg/day, orally), erythropoietin (500 IU/kg every other day, intraperitoneally) and combined (curcumin and erythropoietin)-treated groups. After 3 months of treatment, rats were subjected to neurobehavioral testing, and then killed for biochemical and histological assessment of hippocampus. Fas ligand protein and caspase-8 activity as mediators of extrinsic apoptotic pathway, oxidative stress markers (malondialdehyde and reduced glutathione) and β-amyloid (1-40 and 1-42) peptides were measured. The results showed that administration of erythropoietin suppressed extrinsic apoptosis better than curcumin, while curcumin was more effective in combating oxidative stress in ICV-streptozotocin injected rats. Both erythropoietin and curcumin treatments (individually or combined) equally reduced the hippocampal β-amyloid accumulation and improved cognitive impairment in Morris water maze and passive avoidance tasks. The combined treatment was the most effective in ameliorating apoptosis and oxidative stress rather than behavioral responses or β-amyloid burden. In conclusion, ICV-streptozotocin-induced Alzheimer's dementia activates hippocampal Fas ligand-mediated apoptosis, which could be reduced by erythropoietin and/or curcumin treatment. Curcumin supplementation alone could ameliorate cognitive deficits and reverse biochemical alterations in ICV-streptozotocin Alzheimer's rat model without the hazardous polycythemic effect of long-term erythropoietin injection.
authors.affiliation: Department of Medical Physiology, Faculty of Medicine, Al-Moassat Hospital, University of Alexandria, Egypt. Electronic address: doaa.abdelhady@alexmed.edu.eg.
authors.forename: Doaa M
authors.initials: DM
authors.lastname: Samy
authors.affiliation: Department of Clinical Pharmacology, Faculty of Medicine, Al-Moassat Hospital, University of Alexandria, Egypt. Electronic address: cherine.ismail@alexmed.edu.eg.
authors.forename: Cherine A
authors.initials: CA
authors.lastname: Ismail
authors.affiliation: Department of Medical Biochemistry, Faculty of Medicine, Al-Moassat Hospital, University of Alexandria, Egypt. Electronic address: rasha.nassra@alexmed.edu.eg.
authors.forename: Rasha A
authors.initials: RA
authors.lastname: Nassra
authors.affiliation: Department of Histology and Cell Biology, Faculty of Medicine, Al-Moassat Hospital, University of Alexandria, Egypt. Electronic address: elsaayghs@gmail.com.
authors.forename: Teshreen M
authors.initials: TM
authors.lastname: Zeitoun
authors.affiliation: Department of Chemical Pathology, Medical Research Institute, University of Alexandria, Egypt. Electronic address: azhar.mohmd@yahoo.com.
authors.forename: Azhar M
authors.initials: AM
authors.lastname: Nomair
mesh_terms: D000544:Alzheimer Disease / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology* / Q000503:physiopathology; D016229:Amyloid beta-Peptides / Q000378:metabolism; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects*; D001522:Behavior, Animal / Q000187:drug effects; D003474:Curcumin / Q000494:pharmacology* / Q000627:therapeutic use; D004921:Erythropoietin / Q000494:pharmacology* / Q000627:therapeutic use; D006400:Hematocrit; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D012153:Retention, Psychology / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects*; D065853:Spatial Learning / Q000187:drug effects; D013311:Streptozocin / Q000494:pharmacology*
chemical_list: D016229:Amyloid beta-Peptides; D000975:Antioxidants; D004921:Erythropoietin; D013311:Streptozocin; D003474:Curcumin
keywords: Alzheimer’s; Beta-amyloid 40 (PubChem CID: 57339250); Beta-amyloid 42 (PubChem CID: 57339251); Beta-amyloid peptides; Curcumin; Curcumin (PubChem CID: 969516); Erythropoietin; Extrinsic apoptosis; Malondialdehyde (PubChem CID: 10964); Reduced glutathione (PubChem CID: 7048684); Streptozotocin; Streptozotocin (PubChem CID: 29327)