RESUMO
OBJECTIVES: The present study aimed to identify the effect of memory-related genes on male rats tested for spatial memory with either molar teeth extraction or its restoration by occlusal support using experimental dentures. DESIGN: Memory-related genes were detected from hippocampi of male Wistar rats (exposed to teeth extraction with or without dentures, or no extraction (control)) (7-week old) after behavioural testing (via the radial maze task) using a DNA microarray. The time course of the expression of these genes was evaluated by quantitative real-time polymerase chain reaction (PCR) (on 49-week-old rats). RESULTS: In preliminary experiments, to determine which memory genes are affected by spatial memory training, DNA microarray analysis revealed that thyrotropin-releasing hormone (Trh) and tenascin XA (Tnxa) were up-regulated and neuronatin (Nnat) and S100a9 were down-regulated after the maze training. The expression of Tnxa, Nnat and S100a9 of 49-week-old rats (during the time course) via quantitative real-time PCR was consistent with the results of microarrays of the preliminary experiment. Expression of Trh that was evaluated by quantitative real-time PCR did not agree with the results for this gene from the microarray for all groups. Therefore, expression of Trh may have increased in only young, trained rats. The expression of S100a9 prior to the maze task was down-regulated in only the extraction group. CONCLUSION: These results demonstrated that Trh, Tnxa and Nnat genes were affected according to the degree of memory in male rats. This study also indicated that S100a9 is a memory-related gene, which is affected by the presence of occlusal support.
Assuntos
Calgranulina B/genética , Perfilação da Expressão Gênica , Hipocampo/metabolismo , Memória/fisiologia , Tenascina/genética , Hormônio Liberador de Tireotropina/genética , Extração Dentária , Ácido gama-Aminobutírico/genética , Aminas/metabolismo , Animais , Calgranulina B/metabolismo , Ácidos Cicloexanocarboxílicos/metabolismo , Oclusão Dentária , Gabapentina , Masculino , Aprendizagem em Labirinto , Análise de Sequência com Séries de Oligonucleotídeos , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase em Tempo Real , Tenascina/metabolismo , Hormônio Liberador de Tireotropina/metabolismo , Ácido gama-Aminobutírico/metabolismoRESUMO
EphA4 receptor tyrosine kinase has been shown to be critically involved in neural tissue development. Here, we found EphA4 was also distributed among hypertrophic chondrocytes and osteoblasts in the growth plate of developing mouse long bones. In vitro evaluation revealed that ephA4 expression was elevated upon hypertrophic differentiation of chondrocytes and that markedly stronger expression was observed in osteoblastic SaOS-2 than chondrocytic HCS-2/8 cells. Of note, RNAi-mediated silencing of ephA4 in SaOS-2 cells resulted in the repression of osteocalcin gene expression and alkaline phosphatase activity. Interestingly, confocal laser-scanning microscopic analysis revealed the presence of EphA4 molecules in the nucleus as well as on the surface of SaOS-2 cells. These findings are the first indication of a critical role of EphA4 in ossification, especially at the final stage in which osteoblasts and hypertrophic chondrocytes play major roles.
Assuntos
Condrócitos/enzimologia , Lâmina de Crescimento/enzimologia , Osteoblastos/enzimologia , Osteogênese , Receptor EphA4/metabolismo , Fosfatase Alcalina/genética , Animais , Linhagem Celular , Membrana Celular/enzimologia , Núcleo Celular/enzimologia , Células Cultivadas , Expressão Gênica , Lâmina de Crescimento/crescimento & desenvolvimento , Humanos , Camundongos , Osteocalcina/genética , Interferência de RNA , RNA Interferente Pequeno/genética , Receptor EphA4/genéticaRESUMO
CCN2/connective tissue growth factor (CCN2/CTGF) is a critical signaling modulator of mesenchymal tissue development. This study investigated the localization and expression of CCN2/CTGF as a factor supporting angiogenesis and chondrogenesis during development of secondary ossification centers in the mouse tibial epiphysis. Formation of the secondary ossification center was initiated by cartilage canal formation and blood vessel invasion at 7 days of age, and onset of ossification was observed at 14 days. In situ hybridization showed that CCN2/CTGF mRNA was distinctively expressed in the region of the cartilage canal and capsule-attached marginal tissues at 7 days of age, and distinct expression was also observed in proliferating chondrocytes around the marrow space at 14 days of age. Immunostaining showed that CCN2/CTGF was distributed broadly around the expressed cells located in the central region of the epiphysis, where the chondrocytes become hypertrophic and the cartilage canal enters into the hypertrophic mass. Furthermore, an overlapping distribution of metalloproteinase (MMP)9 and CCN2/CTGF was found in the secondary ossification center. These findings suggest that the CCN2/CTGF is involved in establishing epiphyseal vascularization and remodeling, which eventually determines the secondary ossification center in the developing epiphysial cartilage.
