title: Metformin Improves Functional Recovery After Spinal Cord Injury via Autophagy Flux Stimulation.
abstract: Spinal cord injury (SCI) is a severe neurological disease with few efficacious drugs. Autophagy is a cellular process to confront with stress after SCI and considered to be a therapeutic target of SCI. In this study, we investigated the therapeutic effect of metformin on functional recovery after SCI and its underlying mechanism of autophagy regulation. Using a rat model of traumatic SCI, we found improved function recovery which was paralleled by a reduction of apoptosis after metformin treatment. We further examined autophagy via detecting autophagosomes by transmission electron microscopy and immunofluorescence, as well as autophagy markers by western blot in each groups. The results showed that the number of autophagosomes and expression of autophagy markers such as LC3 and beclin1 were increased in SCI group, while autophagy substrate protein p62 as well as ubiquitinated proteins were found to accumulate in SCI group, indicating an impaired autophagy flux in SCI. But, metformin treatment attenuated the accumulation of p62 and ubiquitinated proteins, suggesting a stimulative effect of autophagy flux by metformin. Blockage of autophagy flux by chloroquine partially abolished the apoptosis inhibition and functional recovery effect of metformin on SCI, which suggested that the protective effect of metformin on SCI was through autophagy flux stimulation. Activation of AMPK as well as inhibition of its downstream mTOR signaling were detected under metformin treatment in vivo and in vitro; inhibition of AMPK signaling by compound C suppressed autophagy flux induced by metformin in vitro, indicating that AMPK signaling was involved in the effect of metformin on autophagy flux regulation. Together, these results illustrated that metformin improved functional recovery effect through autophagy flux stimulation and implied metformin to be a potential drug for SCI therapy.
authors.affiliation: Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China.|Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China.
authors.forename: Di
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China.|Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Xuan
authors.affiliation: Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China.|Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China.
authors.forename: Bin-Bin
authors.initials: BB
authors.lastname: Zheng
authors.affiliation: Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China.|Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China.
authors.forename: Yu-Long
authors.initials: YL
authors.lastname: Zhou
authors.affiliation: Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China.|Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Lin
authors.affiliation: Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China.|Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China.
authors.forename: Yao-Sen
authors.initials: YS
authors.lastname: Wu
authors.affiliation: Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China.|Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China.
authors.forename: Yi-Fei
authors.initials: YF
authors.lastname: Zhou
authors.affiliation: Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China.|Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China.
authors.forename: Yi-Xing
authors.initials: YX
authors.lastname: Huang
authors.affiliation: Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China.|Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China.
authors.forename: Quan
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China.|Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China.
authors.forename: Li-Yan
authors.initials: LY
authors.lastname: Shen
authors.affiliation: Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China.|Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China.
authors.forename: Cong
authors.initials: C
authors.lastname: Mao
authors.affiliation: Department of Orthopaedics, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310058, Zhejiang Province, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China.|Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China.
authors.forename: Xiang-Yang
authors.initials: XY
authors.lastname: Wang
authors.affiliation: Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China. fengnq@163.com.|Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China. fengnq@163.com.
authors.forename: Nai-Feng
authors.initials: NF
authors.lastname: Tian
authors.affiliation: Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China. spinexu@163.com.|Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China. spinexu@163.com.
authors.forename: Hua-Zi
authors.initials: HZ
authors.lastname: Xu
authors.affiliation: Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, 325000, Zhejiang Province, China. callmeroger@126.com.|Zhejiang Provincial Key Laboratory of Orthopaedics, Wenzhou, 325000, Zhejiang Province, China. callmeroger@126.com.|Chinese Orthopaedic Regenerative Medicine Society, Hangzhou, China. callmeroger@126.com.
authors.forename: Xiao-Lei
authors.initials: XL
authors.lastname: Zhang
mesh_terms: D000263:Adenylate Kinase / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D000071182:Autophagosomes / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D001343:Autophagy / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism; D008687:Metformin / Q000494:pharmacology / Q000627:therapeutic use*; D008954:Models, Biological; D009474:Neurons / Q000187:drug effects / Q000473:pathology; D016716:PC12 Cells; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function / Q000187:drug effects; D013119:Spinal Cord Injuries / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism
chemical_list: D008687:Metformin; D058570:TOR Serine-Threonine Kinases; D000263:Adenylate Kinase
keywords: AMPK; Apoptosis; Autophagy flux; Metformin; Spinal cord injury