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Piancino MG, Tortarolo A, Polimeni A, Bramanti E, Bramanti P. Altered mastication adversely impacts morpho-functional features of the hippocampus: A systematic review on animal studies in three different experimental conditions involving the masticatory function. PLoS One 2020; 15:e0237872. [PMID: 32817680 PMCID: PMC7446800 DOI: 10.1371/journal.pone.0237872] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 08/04/2020] [Indexed: 02/06/2023] Open
Abstract
Recent results have established that masticatory function plays a role not only in the balance of the stomatognathic system and in the central motor control, but also in the trophism of the hippocampus and in the cognitive activity. These implications have been shown in clinical studies and in animal researches as well, by means of histological, biochemical and behavioural techniques. This systematic review describes the effects of three forms of experimentally altered mastication, namely soft-diet feeding, molar extraction and bite-raising, on the trophism and function of the hippocampus in animal models. Through a systematic search of PubMed, Embase, Web of Science, Scopus, OpenGray and GrayMatters, 645 articles were identified, 33 full text articles were assessed for eligibility and 28 articles were included in the review process. The comprehensiveness of reporting was evaluated with the ARRIVE guidelines and the risk of bias with the SYRCLE RoB tool. The literature reviewed agrees that a disturbed mastication is significantly associated with a reduced number of hippocampal pyramidal neurons in Cornu Ammonis (CA)1 and CA3, downregulation of Brain Derived Neurotrophic Factor (BDNF), reduced synaptic activity, reduced neurogenesis in the Dentate Gyrus (DG), glial proliferation, and reduced performances in behavioural tests, indicating memory impairment and reduced spatial orientation. Moreover, while the bite-raised condition, characterized by occlusal instability, is known to be a source of stress, soft-diet feeding and molar extractions were not consistently associated with a stress response. More research is needed to clarify this topic. The emerging role of chewing in the preservation of hippocampal trophism, neurogenesis and synaptic activity is worthy of interest and may contribute to the study of neurodegenerative diseases in new and potentially relevant ways.
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Affiliation(s)
- Maria Grazia Piancino
- Department of Surgical Sciences, Dental School, University of Turin, Turin, Italy
- * E-mail:
| | - Alessandro Tortarolo
- Department of Surgical Sciences, Dental School, University of Turin, Turin, Italy
| | - Antonella Polimeni
- Department of Oral and Maxillo-Facial Science, Sapienza University of Rome, Rome, Italy
| | - Ennio Bramanti
- Department of Biomedical and Dental Sciences, Morphological and Functional Images, University of Messina, Messina, Italy
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Pang Q, Wu Q, Hu X, Zhang J, Jiang Q. Tooth loss, cognitive impairment and chronic cerebral ischemia. J Dent Sci 2020; 15:84-91. [PMID: 32257004 PMCID: PMC7109480 DOI: 10.1016/j.jds.2019.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 08/28/2019] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND/PURPOSE Vascular factor is an important risk factor in the process of cognitive impairment or dementia. Tooth loss could cause impairments of spatial learning and memory in mice, and nitric oxide (NO) and its synthase might be involved in the process. The objectives of this study were to investigate and compare the behavioral impairments between the Wistar rats with tooth loss and those with chronic ischemia and to determine the changes in nitric oxide (NO) and its synthases under those two conditions. MATERIALS AND METHODS The Morris water maze was used to test the spatial learning and memory abilities in the Wistar rats 8 weeks after the molar extraction procedure and the occlusion of 2 blood vessels to produce cerebral ischemia. The changes in NO and its synthases were evaluated using the Griess assay, Western blotting, and immunohistochemistry. RESULTS Similar impairments in the spatial learning and memory of Wistar rats were found after tooth loss and the induction of cerebral ischemia. The levels of NO and iNOS in the rat hippocampus increased, and the levels of eNOS decreased. Conclusion: For Wistar rats, the results of cognitive impairments related to tooth loss and those that occur due to chronic cerebral ischemia were statistically not significant and that NO, iNOS and eNOS in the hippocampus are involved in both cases.
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Affiliation(s)
- Qian Pang
- Department of Prosthodontics, Beijing Stomatology Hospital and School of Stomatology, Capital Medical University, Beijing, 100050, China
| | - Qianqian Wu
- Department of Stomatology, People's Hospital of Beijing Daxing District, Capital Medical University, Beijing, 102600, China
| | - Xingxue Hu
- Division of Restorative, Prosthetic and Primary Care Dentistry, College of Dentistry, Ohio State University, OH, 43210, USA
- Dental 28, Lexington, MA, 02420, USA
| | - Jianjun Zhang
- Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Qingsong Jiang
- Department of Prosthodontics, Beijing Stomatology Hospital and School of Stomatology, Capital Medical University, Beijing, 100050, China
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Katano M, Kajimoto K, Iinuma M, Azuma K, Kubo KY. Tooth loss early in life induces hippocampal morphology remodeling in senescence-accelerated mouse prone 8 (SAMP8) mice. Int J Med Sci 2020; 17:517-524. [PMID: 32174782 PMCID: PMC7053313 DOI: 10.7150/ijms.40241] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 01/15/2020] [Indexed: 11/05/2022] Open
Abstract
Long-term tooth loss is associated with the suppression of hippocampal neurogenesis and impairment of hippocampus-dependent cognition with aging. The morphologic basis of the hippocampal alterations, however, remains unclear. In the present study, we investigated whether tooth loss early in life affects the hippocampal ultrastructure in senescence-accelerated mouse prone 8 (SAMP8) mice, using transmission electron microscopy. Male SAMP8 mice were randomized into control or tooth-loss groups. All maxillary molar teeth were removed at 1 month of age. Hippocampal morphologic alterations were evaluated at 9 months of age. Tooth loss early in life induced mitochondrial damage and lipofuscin accumulation in the hippocampal neurons. A thinner myelin sheath and decreased postsynaptic density length were also observed. Our results revealed that tooth loss early in life may lead to hippocampal ultrastructure remodeling and subsequent hippocampus-dependent cognitive impairment in SAMP8 mice with aging.
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Affiliation(s)
- Masahisa Katano
- Department of Pediatric Dentistry, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu, 501-0296, Japan
| | - Kyoko Kajimoto
- Department of Pediatric Dentistry, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu, 501-0296, Japan
| | - Mitsuo Iinuma
- Department of Pediatric Dentistry, Asahi University School of Dentistry, 1851 Hozumi, Mizuho, Gifu, 501-0296, Japan
| | - Kagaku Azuma
- Department of Anatomy, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, Fukuoka, 807-8555, Japan
| | - Kin-Ya Kubo
- Graduate School of Human Life Science, Nagoya Women's University, 3-40 Shioji-cho, Mizuho-ku, Nagoya, Aichi, 467-8610, Japan
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De Cicco V, Tramonti Fantozzi MP, Cataldo E, Barresi M, Bruschini L, Faraguna U, Manzoni D. Trigeminal, Visceral and Vestibular Inputs May Improve Cognitive Functions by Acting through the Locus Coeruleus and the Ascending Reticular Activating System: A New Hypothesis. Front Neuroanat 2018; 11:130. [PMID: 29358907 PMCID: PMC5766640 DOI: 10.3389/fnana.2017.00130] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 12/15/2017] [Indexed: 12/25/2022] Open
Abstract
It is known that sensory signals sustain the background discharge of the ascending reticular activating system (ARAS) which includes the noradrenergic locus coeruleus (LC) neurons and controls the level of attention and alertness. Moreover, LC neurons influence brain metabolic activity, gene expression and brain inflammatory processes. As a consequence of the sensory control of ARAS/LC, stimulation of a sensory channel may potential influence neuronal activity and trophic state all over the brain, supporting cognitive functions and exerting a neuroprotective action. On the other hand, an imbalance of the same input on the two sides may lead to an asymmetric hemispheric excitability, leading to an impairment in cognitive functions. Among the inputs that may drive LC neurons and ARAS, those arising from the trigeminal region, from visceral organs and, possibly, from the vestibular system seem to be particularly relevant in regulating their activity. The trigeminal, visceral and vestibular control of ARAS/LC activity may explain why these input signals: (1) affect sensorimotor and cognitive functions which are not directly related to their specific informational content; and (2) are effective in relieving the symptoms of some brain pathologies, thus prompting peripheral activation of these input systems as a complementary approach for the treatment of cognitive impairments and neurodegenerative disorders.
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Affiliation(s)
- Vincenzo De Cicco
- Laboratory of Sensorimotor Integration, Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
| | - Maria P Tramonti Fantozzi
- Laboratory of Sensorimotor Integration, Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
| | | | - Massimo Barresi
- Institut des Maladie Neurodégénératives, University of Bordeaux, Bordeaux, France
| | - Luca Bruschini
- Department of Surgical, Medical, Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy
| | - Ugo Faraguna
- Laboratory of Sensorimotor Integration, Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, Pisa, Italy.,Department of Developmental Neuroscience, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Diego Manzoni
- Laboratory of Sensorimotor Integration, Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, Pisa, Italy
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Tramonti Fantozzi MP, De Cicco V, Barresi M, Cataldo E, Faraguna U, Bruschini L, Manzoni D. Short-Term Effects of Chewing on Task Performance and Task-Induced Mydriasis: Trigeminal Influence on the Arousal Systems. Front Neuroanat 2017; 11:68. [PMID: 28848404 PMCID: PMC5550729 DOI: 10.3389/fnana.2017.00068] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 07/24/2017] [Indexed: 12/19/2022] Open
Abstract
Trigeminal input to the ascending activating system is important for the maintenance of arousal and may affect the discharge of the noradrenergic neurons of the locus coeruleus (LC), whose activity influences both vigilance state and pupil size, inducing mydriasis. For this reason, pupil size evaluation is now considered an indicator of LC activity. Since mastication activates trigeminal afferent neurons, the aims of the present study, conducted on healthy adult participants, were to investigate whether chewing a bolus of different hardness may: (1) differentially affect the performance on a cognitive task (consisting in the retrieval of specific target numbers within numerical matrices) and (2) increase the dilatation of the pupil (mydriasis) induced by a haptic task, suggesting a change in LC activation. Results show that chewing significantly increased both the velocity of number retrieval (without affecting the number of errors) and the mydriasis associated with the haptic task, whereas simple task repetition did not modify either retrieval or mydriasis. Handgrip exercise, instead, significantly decreased both parameters. Effects were significantly stronger and longer lasting when subjects chewed hard pellets. Finally, chewing-induced improvements in performance and changes in mydriasis were positively correlated, which suggests that trigeminal signals enhanced by chewing may boost the cognitive performance by increasing LC activity.
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Affiliation(s)
| | - Vincenzo De Cicco
- Department of Translational Research and of New Surgical and Medical Technologies, University of PisaPisa, Italy
| | - Massimo Barresi
- Institut des Maladies Neurodégénératives, University of BordeauxBordeaux, France
| | | | - Ugo Faraguna
- Department of Translational Research and of New Surgical and Medical Technologies, University of PisaPisa, Italy.,Department of Developmental Neuroscience, IRCCS Foundation Stella MarisPisa, Italy
| | - Luca Bruschini
- Department of Surgical, Medical, Molecular Pathology and Critical Care Medicine, University of PisaPisa, Italy
| | - Diego Manzoni
- Department of Translational Research and of New Surgical and Medical Technologies, University of PisaPisa, Italy
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Association between Mastication, the Hippocampus, and the HPA Axis: A Comprehensive Review. Int J Mol Sci 2017; 18:ijms18081687. [PMID: 28771175 PMCID: PMC5578077 DOI: 10.3390/ijms18081687] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 07/31/2017] [Accepted: 08/01/2017] [Indexed: 12/29/2022] Open
Abstract
Mastication is mainly involved in food intake and nutrient digestion with the aid of teeth. Mastication is also important for preserving and promoting general health, including hippocampus-dependent cognition. Both animal and human studies indicate that mastication influences hippocampal functions through the end product of the hypothalamic-pituitary-adrenal (HPA) axis, glucocorticoid (GC). Epidemiologic studies suggest that masticatory dysfunction in aged individuals, such as that resulting from tooth loss and periodontitis, acting as a source of chronic stress, activates the HPA axis, leading to increases in circulating GCs and eventually inducing various physical and psychological diseases, such as cognitive impairment, cardiovascular disorders, and osteoporosis. Recent studies demonstrated that masticatory stimulation or chewing during stressful conditions suppresses the hyperactivity of the HPA axis via GCs and GC receptors within the hippocampus, and ameliorates chronic stress-induced hippocampus-dependent cognitive deficits. Here, we provide a comprehensive overview of current research regarding the association between mastication, the hippocampus, and HPA axis activity. We also discuss several potential molecular mechanisms involved in the interactions between mastication, hippocampal function, and HPA axis activity.
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Kondo H, Uchida M, Ichihashi Y, Suzuki A, Hayashi S, Iinuma M, Azuma K, Kubo KY. Maternal occlusal disharmony during pregnancy induces spatial memory deficits associated with the suppression of hippocampal neurogenesis in adult mouse offspring. PEDIATRIC DENTAL JOURNAL 2017. [DOI: 10.1016/j.pdj.2016.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Kojo A, Yamada K, Yamamoto T. Glucose transporter 5 (GLUT5)-like immunoreactivity is localized in subsets of neurons and glia in the rat brain. J Chem Neuroanat 2016; 74:55-70. [PMID: 27036089 DOI: 10.1016/j.jchemneu.2016.03.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 03/24/2016] [Accepted: 03/24/2016] [Indexed: 12/13/2022]
Abstract
This study aimed at examining the distribution of glucose transporter 5 (GLUT5), which preferentially transports fructose, in the rat brain by immunohistochemistry and Western blotting. Small immunoreactive puncta (less than 0.7μm) were sparsely distributed all over the brain, some of which appeared to be associated with microglial processes detected by an anti-ionized calcium-binding adapter molecule 1 (Iba-1) monoclonal antibody. In addition, some of these immunoreactive puncta seemed to be associated with tanycyte processes that were labeled with anti-glial fibrillary acidic protein (GFAP) monoclonal antibody. Ependymal cells were also found to be immunopositive for GLUT5. Furthermore, several noticeable GLUT5 immunoreactive profiles were observed. GLUT5 immunoreactive neurons, confirmed by double staining with neuronal nuclei (NeuN), were seen in the entopeduncular nucleus and lateral hypothalamus. Cerebellar Purkinje cells were immunopositve for GLUT5. Dense accumulation of immunoreactive puncta, some of which were neuronal elements (confirmed by immunoelectron microscopy), were observed in the optic tract and their terminal fields, namely, superior colliculus, pretectum, nucleus of the optic tract, and medial terminal nucleus of the optic tract. In addition to the associated areas of the visual system, the vestibular and cochlear nuclei also contained dense GLUT5 immunoreactive puncta. Western blot analysis of the cerebellum indicated that the antibody used recognized the 33.5 and 37.0kDa bands that were also contained in jejunum and kidney extracts. Thus, these results suggest that GLUT5 may transport fructose in subsets of the glia and neurons for an energy source of these cells.
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Affiliation(s)
- Akiko Kojo
- Division of Medical Nutrition, Faculty of Healthcare, Tokyo Healthcare University, Setagaya-ku, Tokyo 154-8568, Japan
| | - Kentaro Yamada
- Department of Oral Science, Division of Neuroscience and Brain Functions, Kanagawa Dental University, Yokosuka 238-8580, Japan
| | - Toshiharu Yamamoto
- Department of Oral Science, Division of Neuroscience and Brain Functions, Kanagawa Dental University, Yokosuka 238-8580, Japan.
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De Cicco V, Barresi M, Tramonti Fantozzi MP, Cataldo E, Parisi V, Manzoni D. Oral Implant-Prostheses: New Teeth for a Brighter Brain. PLoS One 2016; 11:e0148715. [PMID: 26919258 PMCID: PMC4771091 DOI: 10.1371/journal.pone.0148715] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 12/15/2015] [Indexed: 12/22/2022] Open
Abstract
Several studies have demonstrated that chewing can be regarded as a preventive measure for cognitive impairment, whereas masticatory deficiency, associated with soft-diet feeding, is a risk factor for the development of dementia. At present the link between orofacial sensorimotor activity and cognitive functions is unknown. In subjects with unilateral molar loss we have shown asymmetries in both pupil size and masticatory muscles electromyographic (EMG) activity during clenching: the molar less side was characterized by a lower EMG activity and a smaller pupil. Since implant-prostheses, greatly reduced both the asymmetry in EMG activity and in pupil's size, trigeminal unbalance, leading to unbalance in the activity of the Locus Coeruleus (LC), may be responsible for the pupil's asymmetry. According to the findings obtained in animal models, we propose that the different activity of the right and left LC may induce an asymmetry in brain activity, thus leading to cognitive impairment. According to this hypothesis, prostheses improved the performance in a complex sensorimotor task and increased the mydriasis associated with haptic tasks. In conclusion, the present study indicates that the implant-prosthesis therapy, which reduces the unbalance of trigeminal proprioceptive afferents and the asymmetry in pupil's size, may improve arousal, boosting performance in a complex sensorimotor task.
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Affiliation(s)
- Vincenzo De Cicco
- Department of Translational Research, University of Pisa, Pisa, Italy
| | - Massimo Barresi
- Department of Drug Sciences, University of Catania, Catania, Italy
| | | | | | | | - Diego Manzoni
- Department of Translational Research, University of Pisa, Pisa, Italy
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Pang Q, Hu X, Li X, Zhang J, Jiang Q. Behavioral impairments and changes of nitric oxide and inducible nitric oxide synthase in the brains of molarless KM mice. Behav Brain Res 2014; 278:411-6. [PMID: 25447296 DOI: 10.1016/j.bbr.2014.10.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 10/14/2014] [Accepted: 10/17/2014] [Indexed: 01/24/2023]
Abstract
More studies showed that as a common disorder in senior population, loss of teeth could adversely affect human cognitive function, and nitric oxide (NO) might play an important role in the cognitive function. However, the underlying mechanism has not yet been well-established. The objectives of this study are to evaluate behavior changes of KM mice after loss of molars, and levels of NO and inducible nitric oxide synthase (iNOS) in the brain in molarless condition. It is hypothesized that loss of molars of the mice tested results in the cognitive impairments and that the process is mediated by NO in the brain through the signaling pathways. Morris water maze is used to test the behavioral changes after 8 weeks of the surgery. The changes of NO and iNOS are evaluated by using Griess assay, western blot, and immunohistochemistry method. The results show that 8 weeks after loss of molars, the spatial learning and memory of KM mice impair and the levels of NO and iNOS in mice hippocampus increase. These findings suggest that molar extraction is associated with the behavioral impairment, and that the changes of NO and iNOS in the hippocampus may be involved in the behavioral changes in the molarless condition.
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Affiliation(s)
- Qian Pang
- Department of Prosthodontics, Beijing Stomatology Hospital and School of Stomatology, Capital Medical University, Beijing 100050, China
| | - Xingxue Hu
- Advanced Standing Program, Boston University Henry M. Goldman School of Dental Medicine, 100 East Newton Street, Boston, MA 02118, USA
| | - Xinya Li
- Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Jianjun Zhang
- Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Qingsong Jiang
- Department of Prosthodontics, Beijing Stomatology Hospital and School of Stomatology, Capital Medical University, Beijing 100050, China.
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Patten A, Moller D, Graham J, Gil-Mohapel J, Christie B. Liquid diets reduce cell proliferation but not neurogenesis in the adult rat hippocampus. Neuroscience 2013; 254:173-84. [DOI: 10.1016/j.neuroscience.2013.09.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 09/11/2013] [Accepted: 09/11/2013] [Indexed: 12/22/2022]
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Frota de Almeida MN, de Siqueira Mendes FDCC, Gurgel Felício AP, Falsoni M, Ferreira de Andrade ML, Bento-Torres J, da Costa Vasconcelos PF, Perry VH, Picanço-Diniz CW, Kronka Sosthenes MC. Spatial memory decline after masticatory deprivation and aging is associated with altered laminar distribution of CA1 astrocytes. BMC Neurosci 2012; 13:23. [PMID: 22376223 PMCID: PMC3355053 DOI: 10.1186/1471-2202-13-23] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 02/29/2012] [Indexed: 01/27/2023] Open
Abstract
Background Chewing imbalances are associated with neurodegeneration and are risk factors for senile dementia in humans and memory deficits in experimental animals. We investigated the impact of long-term reduced mastication on spatial memory in young, mature and aged female albino Swiss mice by stereological analysis of the laminar distribution of CA1 astrocytes. A soft diet (SD) was used to reduce mastication in the experimental group, whereas the control group was fed a hard diet (HD). Assays were performed in 3-, 6- and 18-month-old SD and HD mice. Results Eating a SD variably affected the number of astrocytes in the CA1 hippocampal field, and SD mice performed worse on water maze memory tests than HD mice. Three-month-old mice in both groups could remember/find a hidden platform in the water maze. However, 6-month-old SD mice, but not HD mice, exhibited significant spatial memory dysfunction. Both SD and HD 18-month-old mice showed spatial memory decline. Older SD mice had astrocyte hyperplasia in the strata pyramidale and oriens compared to 6-month-old mice. Aging induced astrocyte hypoplasia at 18 months in the lacunosum-moleculare layer of HD mice. Conclusions Taken together, these results suggest that the impaired spatial learning and memory induced by masticatory deprivation and aging may be associated with altered astrocyte laminar distribution and number in the CA1 hippocampal field. The underlying molecular mechanisms are unknown and merit further investigation.
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Affiliation(s)
- Marina Negrão Frota de Almeida
- Universidade Federal do Pará-UFPA, Instituto de Ciências Biológicas, Laboratório de Investigações em Neurodegeneração e Infecção, Hospital Universitário João de Barros Barreto, Belém, PA, Brazil
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Occlusal disharmony increases amyloid-β in the rat hippocampus. Neuromolecular Med 2011; 13:197-203. [PMID: 21751079 DOI: 10.1007/s12017-011-8151-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Accepted: 06/25/2011] [Indexed: 12/20/2022]
Abstract
Amyloid-β plays a causative role in Alzheimer's disease. Occlusal disharmony causes chronic psychological stress, and psychological stress increases amyloid-β accumulation. The purpose of the present study was to investigate whether occlusal disharmony-induced psychological stress affects the accumulation of amyloid-β and its related gene expressions in the rat hippocampus. Eight-week-old male Wistar rats (n = 18) were divided into three groups of six rats each: (1) a control group that received no treatment for 8 weeks; (2) an occlusal disharmony group that underwent cutoff maxillary molar cusps for 8 weeks; and (3) a recovered group that underwent cutoff maxillary molar cusps for 4 weeks followed by recovery for 4 weeks. Occlusal disharmony increased plasma corticosterone levels in a time-dependent manner. Levels of amyloid-β 40 and 42, glucocorticoid receptor (Gr) protein, and cleaved caspase 3 (Casp3) as well as gene expressions of amyloid precursor protein, beta-secretase, Casp3, and Gr in the hippocampus in the occlusal disharmony group were significantly higher than those in the control group (P < 0.016). These findings were significantly improved by recovery of occlusion (P < 0.016). These results indicate that psychological stress induced by occlusal disharmony reversibly induces amyloid-β 40 and 42 in the rat hippocampus through the glucocorticoid signal.
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Yoo DY, Yoo KY, Choi JW, Kim W, Lee CH, Choi JH, Park JH, Won MH, Hwang IK. Time course of postnatal distribution of doublecortin immunoreactive developing/maturing neurons in the somatosensory cortex and hippocampal CA1 region of C57BL/6 mice. Cell Mol Neurobiol 2011; 31:729-36. [PMID: 21360195 DOI: 10.1007/s10571-011-9670-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 02/18/2011] [Indexed: 11/25/2022]
Abstract
In this study, we observed neuroblast differentiation in the somatosensory cortex (SSC) and hippocampal CA1 region (CA1), which is vulnerable to oxidative stress, of the mouse at various early postnatal days (P) 1, 7, 14, and 21 using doublecortin (DCX, a marker for neuroblasts). Cresyl violet and NeuN (Neuronal Nuclei) staining showed development of layers as well as neurons in the SSC and CA1. At P1, DCX-positive neuroblasts expressed strong DCX immunoreactivity in both the SSC and CA1. Thereafter, DCX immunoreactivity was decreased with time. At P7, many DCX-immunoreactive neuroblasts were well detected in the SSC and CA1. At P14, some DCX-positive neuroblasts were found in the SSC and CA1: The immunoreactivity was weak. At P21, DCX immunoreactivity was hardly found in cells in the SSC and CA1. These results suggest that DCX-positive neuroblasts were significantly decreased in the mouse SSC and CA1 from P14.
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Affiliation(s)
- Dae Young Yoo
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, South Korea
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15
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Occlusal disharmony induces BDNF level in rat submandibular gland. Arch Oral Biol 2011; 56:35-40. [DOI: 10.1016/j.archoralbio.2010.09.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 08/19/2010] [Accepted: 09/06/2010] [Indexed: 11/17/2022]
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