title: Relationship between [corrected] spatial memory in diabetic rats and protein kinase Cγ, caveolin-1 in the hippocampus and neuroprotective effect of catalpol.
abstract: BACKGROUND
  The mechanisms underlying diabetic encephalopathy are largely unknown, and no effective treatments are available. Catalpol has received much attention due to its numerous biological effects, especially in neuroprotective studies. The aim of this study was to investigate the effects of catalpol on cognitive functions in diabetic rats and the underlying mechanisms.
  
  
  METHODS
  A rat model of diabetes was established by streptozotocin injection, followed by intraperitoneal infusion of catalpol after 10 weeks. Two weeks later, the Morris water maze was used to test the spatial learning performance. Nissl staining was performed to evaluate the morphological changes in the hippocampus. Expression of protein kinase Cγ (PKCγ) and caveolin-1 (Cav-1) in the hippocampus were assessed by reverse transcription PCR and Western blotting. Activities of anti-oxidative enzymes such as glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) and levels of malonaldehyde (MDA) were measured using commercial kits.
  
  
  RESULTS
  Significant hippocampal neuronal injury was observed in rats with streptozotocin-induced diabetes. Moreover, cognitive dysfunction was associated with markedly increased oxidative stress in the brain. Catalpol treatment significantly attenuated cognitive deficits, neuronal damage, and oxidative stress in the brain of diabetic rats. Biochemical analyses showed that catalpol reversed the down-regulation of PKCγ and Cav-1 expression in the diabetic rats.
  
  
  CONCLUSIONS
  Spatial memory in diabetic rats is associated with the expression of PKCγ and Cav-1. Catalpol treatment markedly attenuated oxidative stress, reversed the alteration of PKCγ, Cav-1 and spatial memory deficits.
authors.affiliation: Department of Endocrinology, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, China.
authors.forename: Haicheng
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Institute of Integrative Medicine, Dalian Medical University, Dalian, Liaoning 116044, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Endocrinology, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, China; Department of Endocrinology, Friendship Hospital of Dalian, Dalian, Liaoning 116001, China.
authors.forename: Liyuan
authors.initials: L
authors.lastname: Ren
authors.affiliation: Department of Endocrinology, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, China; Department of Endocrinology, First People's Hospital of Shenyang, Shenyang, Liaoning 110041, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Endocrinology, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Xing
authors.affiliation: Department of Endocrinology, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Men
authors.affiliation: Department of Health Statistics, Dalian Medical University, Dalian, Liaoning 116044, China.
authors.forename: Guirong
authors.initials: G
authors.lastname: Song
authors.affiliation: Department of Endocrinology, First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, China. Email: dujianling63@163.com.
authors.forename: Jianling
authors.initials: J
authors.lastname: Du
mesh_terms: D000818:Animals; D051242:Caveolin 1 / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D057888:Iridoid Glucosides / Q000627:therapeutic use*; D008297:Male; D018696:Neuroprotective Agents / Q000627:therapeutic use*; D018384:Oxidative Stress / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D065852:Spatial Memory / Q000187:drug effects / Q000502:physiology*
chemical_list: D051242:Caveolin 1; D057888:Iridoid Glucosides; D018696:Neuroprotective Agents; C078040:catalpol; C087857:protein kinase C gamma; D011493:Protein Kinase C