Navegando por Palavras-chave "bone formation"

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    Absence of Cx43 selectively from osteocytes enhances responsiveness to mechanical force in mice
    (Wiley-Blackwell, 2013-07-01) Bivi, Nicoletta; Costa, Rafael Pacheco da [UNIFESP]; Brun, Lucas R.; Murphy, Thomas R.; Farlow, Nathan R.; Robling, Alexander G.; Bellido, Teresita; Plotkin, Lilian I.; Indiana Univ Sch Med; Universidade Federal de São Paulo (UNIFESP); Richard L Roudebush Vet Adm Med Ctr
    The osteocyte network is crucial for the response of bone to mechanical force. Within this network, connexin43 (Cx43) is thought to mediate the communication of osteocytes and osteoblasts among themselves and the exchange of small molecules with the extracellular milieu. Despite recent advances in understanding Cx43 role for the response of bone cells to mechanical stimulation, the contribution of Cx43 specifically in osteocytes to mechanotransduction in vivo is not well-known. We examined the anabolic response to ulnar axial loading of mice lacking Cx43 in osteocytes (Cx43Ot). Loading induced a greater increase in periosteal bone formation rate in Cx43Ot mice compared to control littermates, resulting from higher mineralizing surface and enhanced mineral apposition rate. Expression of -catenin protein, a molecule implicated in mechanotransduction, was higher in bones from Cx43Ot mice, compared to littermate controls. in addition, MLO-Y4 osteocytic cells knocked-down for Cx43 exhibited higher -catenin protein expression and enhanced response to mechanical stimulation. These findings suggest that osteocytes lacking Cx43 are primed to respond to mechanical stimulation and that absence of Cx43 in osteocytes unleashes bone formation, by a mechanism that might involve accumulation of -catenin. (c) 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:10751081, 2013
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    Effects of cigarette smoke inhalation and coffee consumption on bone formation and osseous integration of hydroxyapatite implant
    (Instituto Internacional de Ecologia, 2013-02-01) Andrade, Ana R.; Sant'ana, Dcm.; Mendes Junior, Ja.; Moreira, Maria Eliza Castro; Pires, Gc.; Santos, Mp.; Fernandes, Geraldo Jose Medeiros [UNIFESP]; Nakagaki, Wilson Romero; Garcia, Jad.; Lima, Cc.; Soares, Ea.; Universidade José do Rosário Vellano; Universidade Federal de São Paulo (UNIFESP); Universidade Federal de Alfenas; Universidade Estadual de Campinas (UNICAMP); Universidade José do Rosário Vellano Faculdade de Medicina
    The present study aims to assess the effects of cigarette smoke inhalation and/or coffee consumption on bone formation and osseous integration of a dense hydroxyapatite (DHA) implant in rats. For this study, 20 male rats were divided into four groups (n = 5): CT (control) group, CE (coffee) group, CI (cigarette) group and CC (coffee + cigarette) group. During 16 weeks, animals in the CI group were exposed to cigarette smoke inhalation equivalent to 6 cigarettes per day; specimens in the CE group drank coffee as liquid diet; and rats in the CC group were submitted to both substances. In the 6th week a 5 mm slit in the parietal bone and a 4 mm slit in the tibia were performed on the left side: the former was left open while the latter received a DHA implant. As soon as surgeries were finished, the animals returned to their original protocols and after 10 weeks of exposure they were euthanised (ethically sacrificed) and the mentioned bones collected for histological processing. Data showed that exposure to cigarette smoke inhalation and coffee consumption did not interfere in weight gain and that solid and liquid diet consumption was satisfactory. Rats in the CC group showed a decrease in bone neoformation around the tibial DHA implant (31.8 ± 2.8) as well as in bone formation in the parietal slit (28.6 ± 2.2). On their own, cigarette smoke inhalation or coffee consumption also led to diminished bone neoformation around the implant and delayed the bone repair process in relation to the CT group. However, reduction in the bone repair process was accentuated with exposure to both cigarette smoke inhalation and coffee consumption in this study.