title: G-CSF and cognitive dysfunction in elderly diabetic mice with cerebral small vessel disease: Preventive intervention effects and underlying mechanisms.
abstract: OBJECTIVE
  Although cognitive dysfunction is a common neurological complication in elderly patients with diabetes, the mechanisms underlying this relationship remain unclear, and effective preventive interventions have yet to be developed. Thus, this study investigated the preventive effects and mechanisms of action associated with granulocyte colony-stimulating factor (G-CSF) on cognitive dysfunction in elderly diabetic mice with cerebral small vessel disease.
  
  
  METHODS
  This study included 40 male db/db diabetic and wild-type (WT) mice that were categorized into the following four groups at the age of 3 weeks: db/db group (DG), db/db+G-CSF group (DGG), WT group (WG), and WT+G-CSF group (WGG). The mice were fed normal diets for 4 months and then given G-CSF (75 μg/kg) via intraperitoneal injections for 1 month. At 7.5 months of age, the cognitive abilities of the mice were assessed with the Y-maze test and the Social Choice Test; body weight, blood pressure (BP), and blood glucose measurements were obtained throughout the study. Brain imaging and blood oxygen level-dependent (BOLD) contrast imaging analyses were performed with a small animal magnetic resonance imaging (MRI) system, autophagosome levels were detected with a transmission electron microscope (TEM), hippocampal neurons were assessed with hematoxylin and eosin (HE) staining, and protein expressions and distributions were evaluated using immunohistochemistry and Western blot analyses.
  
  
  RESULTS
  (i) The body weight and blood glucose levels of the DG and DGG mice were significantly higher than those of the WG and WGG mice; (ii) social choice and spatial memory capabilities were significantly reduced in DG mice but were recovered by G-CSF in DGG mice; (iii) the MRI scans revealed multiple lacunar lesions and apparent hippocampal atrophy in the brains of DG mice, but G-CSF reduced the number of lacunar lesions and ameliorated hippocampal atrophy; (iv) the MRI-BOLD scans showed a downward trend in whole-brain activity and reductions in the connectivities of the hippocampus and amygdala with subcortical structures in DG mice, but G-CSF clearly improved the altered brain activity as well as the connectivity of the hippocampus in DGG mice; (v) HE staining revealed fewer neurons in the hippocampus in DG mice; (vi) TEM analyses revealed significantly fewer autophagosomes in the hippocampi of DG mice, but G-CSF did not increase these numbers; (vii) there were significant reductions in mechanistic target of rapamycin (mTOR) and LC3-phosphatidylethanolamine conjugate (LC3)-II/I levels in the hippocampi of DG mice, whereas p62 was upregulated, and G-CSF significantly enhanced the levels of Beclin1, mTOR, and LC-II/I in DGG mice; and (viii) G-CSF significantly reversed increases in nuclear factor κB (NF-κB) protein levels in DG but not in WG mice.
  
  
  CONCLUSIONS
  In this study, aged diabetic mice were prone to cognitive dysfunction and cerebral small vessel disease. However, administration of G-CSF significantly improved cognitive function in elderly db/db diabetic mice, and this change was likely related to the regulation of autophagy and NF-κB signaling pathways.
authors.affiliation: Department of Geriatric Neurology, Huashan Hospital, Fudan University, Shanghai, China.|State Key Laboratory of Medical Neurobiology, Institute of Brain Science, Fudan University, Shanghai, China.
authors.forename: Zhu-Fei
authors.identifier: http://orcid.org/0000-0003-0778-6483
authors.initials: ZF
authors.lastname: Guan
authors.affiliation: Department of General Medicine, Ouyang Community Health Service Center, Hongkou District, Shanghai, China.
authors.forename: Ying-Hong
authors.initials: YH
authors.lastname: Tao
authors.affiliation: Department of Geriatric Neurology, Huashan Hospital, Fudan University, Shanghai, China.
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Medical Neurobiology, Institute of Brain Science, Fudan University, Shanghai, China.
authors.forename: Qi-Lin
authors.initials: QL
authors.lastname: Guo
authors.affiliation: Department of Neurosurgery, Shandong Provincial Hospital, Jinan, China.
authors.forename: Ying-Chao
authors.initials: YC
authors.lastname: Liu
authors.affiliation: Department of Geriatric Neurology, Huashan Hospital, Fudan University, Shanghai, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Geriatric Neurology, Huashan Hospital, Fudan University, Shanghai, China.
authors.forename: Yan-Mei
authors.initials: YM
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Medical Neurobiology, Institute of Brain Science, Fudan University, Shanghai, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Ji
authors.affiliation: Department of Emergency Neurology, Affiliated Hospital, Guiyang Medical University, Guiyang, China.
authors.forename: Guo-Feng
authors.initials: GF
authors.lastname: Wu
authors.affiliation: Department of Geriatric Neurology, Huashan Hospital, Fudan University, Shanghai, China.
authors.forename: Na-Na
authors.initials: NN
authors.lastname: Wang
authors.affiliation: Department of Geriatric Neurology, Huashan Hospital, Fudan University, Shanghai, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Yang
authors.affiliation: Department of Geriatric Neurology, Huashan Hospital, Fudan University, Shanghai, China.
authors.forename: Zhong-Yu
authors.initials: ZY
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Medical Neurobiology, Institute of Brain Science, Fudan University, Shanghai, China.
authors.forename: Jing-Chun
authors.initials: JC
authors.lastname: Guo
authors.affiliation: Department of Geriatric Neurology, Huashan Hospital, Fudan University, Shanghai, China.
authors.forename: Hou-Guang
authors.initials: HG
authors.lastname: Zhou
mesh_terms: D000375:Aging; D000818:Animals; D001786:Blood Glucose / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D059345:Cerebral Small Vessel Diseases / Q000097:blood / Q000150:complications* / Q000000981:diagnostic imaging; D002755:Choice Behavior; D003072:Cognition Disorders / Q000097:blood / Q000000981:diagnostic imaging / Q000209:etiology* / Q000517:prevention & control*; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000150:complications* / Q000000981:diagnostic imaging / Q000235:genetics; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology / Q000627:therapeutic use*; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D010100:Oxygen / Q000097:blood; D051381:Rats; D012919:Social Behavior; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism
chemical_list: D001786:Blood Glucose; D016179:Granulocyte Colony-Stimulating Factor; D008869:Microtubule-Associated Proteins; D010100:Oxygen; D058570:TOR Serine-Threonine Kinases; C526109:Anxa3 protein, rat; C546845:mTOR protein, rat
keywords: G-CSF; NF-κB; autophagy; cerebral small vessel disease; cognitive dysfunction; elderly diabetic mice