Intraperitoneal Carbamylated erythropoietin improves memory and hippocampal apoptosis in beta-amyloid rat model of Alzheimer’s disease through stimulating autophagy and inhibiting necroptosis

Abstract

Introduction: Alzheimer’s disease (AD) is marked by the deposition of amyloid-β (Aβ) plaques and tau tangles. Although Erythropoietin (EPO) provides neuroprotective and memory-improving properties, its application has been limited due to the hematopoietic effects. Carbamylated Erythropoietin-Fc (CEPO-Fc) was developed as a non-erythropoietic EPO derivative that possesses neuroprotective potential. However, the molecular mechanisms behind the protective effects of CEPO-Fc’s in AD are still under consideration. Therefore, herein investigated the therapeutic properties of intraperitoneal (i.p.) dose of CEPO-Fc on Aβ-induced neurotoxicity in adult male Wistar rats. Methods: The rats received microinjections of Aβ25-35 (5 μg/2.5 μl, per side) in the dorsal hippocampus for four consecutive days. CEPO-Fc was injected intraperitoneally in two doses of 500 and 5000 IU during the next six days. Learning and memory performance were studied (days 10-13) using the Morris Water Maze task. Immunoblotting was also undertaken to assess the molecular levels of leading indicators of apoptosis (Bax, Bcl-2, and caspase-3), necroptosis (Phosphorylated-Receptor-interacting serine/threonine-protein kinase 3 (p-RIP3)), as well as autophagy (phosphorylated-Beclin-1 (p-Beclin-1) and phosphorylated-1A/1B-light chain 3 (p-LC3-II)) in the hippocampus. Results: Behavioral analysis indicated that CEPO-Fc 500 and 5000 IU reversed memory impairment. Moreover, the hippocampus’s molecular study showed upregulation of P-LC3-II/LC3-II and suppression of Bax/Bcl-2, Caspase-3, and P-RIP3/RIP3 processes. Conclusion: Our findings imply that the neuroprotective characteristics of CEPO-Fc in the AD rats are mediated through autophagy activation and regulation of apoptosis and necroptosis processes. These results suggest that an i.p. dose of CEPO-Fc could be used to protect against AD-induced neurotoxicity.