title: Molar loss and powder diet leads to memory deficit and modifies the mRNA expression of brain-derived neurotrophic factor in the hippocampus of adult mice.
abstract: It is known that tooth loss is known to be a risk factor for Alzheimer's disease and soft diet feeding induces memory impairment. Recent studies have shown that brain-derived neurotrophic factor (BDNF) is associated with tooth loss or soft diet in young animal model, and that BDNF expression is decreased in patients with Alzheimer's disease. However, single or combined effect of tooth loss and/or soft diet on brain function has not fully understood. Here we examined the effect of molar loss and powder diet on memory ability and the expression of BDNF mRNA in the hippocampus of adult C57BL/6J mice. Twenty eight-weeks-old C57BL/6J mice were divided into intact molar group and extracted molar group. They were randomly divided into the I/S group (Intact upper molar teeth/Solid diet feeding), the E/S group (Extracted upper molar teeth/Solid diet feeding), the I/P group (Intact upper molar teeth/Powder diet feeding), and the E/P group (Extracted upper molar teeth/Powder diet feeding). The observation periods were 4 and 16-week. To analyze the memory ability, the step-through passive avoidance test was conducted. BDNF-related mRNA in the hippocampus was analyzed by real-time polymerase chain reaction (RT-PCR).
  
  
  
  At 4 weeks later, we performed memory test and isolated brains to analyze. There were no differences in memory function and BDNF mRNA level between these four groups. However, at 16 weeks later, E/S and E/P group showed memory impairment, and decreased level of BDNF mRNA. Whereas, the powder diet had no effect on memory function and BDNF mRNA level even at 16 weeks later.
  
  
  
  These results suggest that the effect of molar loss and powder diet on memory function and BDNF mRNA levels were different, molar loss may have a greater long-term effect on memory ability than powder diet does.
authors.affiliation: Department of Advanced Prosthodontics, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Takeda
authors.affiliation: Department of Advanced Prosthodontics, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan. hiroshi-o@hiroshima-u.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Oue
authors.affiliation: Department of Advanced Prosthodontics, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Okada
authors.affiliation: Department of Advanced Prosthodontics, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kawano
authors.affiliation: Department of Advanced Prosthodontics, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Koretake
authors.affiliation: Department of Biochemistry, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Michikawa
authors.affiliation: Department of Advanced Prosthodontics, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Akagawa
authors.affiliation: Department of Advanced Prosthodontics, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Tsuga
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000502:physiology; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics / Q000378:metabolism*; D004032:Diet / Q000009:adverse effects*; D004195:Disease Models, Animal; D006624:Hippocampus / Q000378:metabolism* / Q000473:pathology; D007031:Hypothalamus / Q000378:metabolism; D008297:Male; D008568:Memory / Q000502:physiology; D008569:Memory Disorders / Q000209:etiology* / Q000378:metabolism* / Q000473:pathology; D008810:Mice, Inbred C57BL; D008963:Molar; D012333:RNA, Messenger / Q000378:metabolism; D011897:Random Allocation; D020813:Receptor, trkB / Q000378:metabolism; D013997:Time Factors; D016388:Tooth Loss / Q000150:complications* / Q000378:metabolism / Q000473:pathology / Q000523:psychology
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D012333:RNA, Messenger; D020813:Receptor, trkB
keywords: Brain-derived neurotrophic factor; Memory deficit; Molar loss; Powder diet