Spaceflight Inhibits Bone Formation Independent of Corticosteroid Status in Growing Rats

Zérath, E.; Holy, Xavier; Roberts, Sydney G.; André, Catherine; Renault, Sylvie; Hott, M.; Marie, Pierre J.

doi:10.1359/jbmr.2000.15.7.1310

Cited by 45 publications

(31 citation statements)

References 53 publications

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“…Reports have indicated that adrenocortical hormones have aindica range of effects on different body systems [6]. Our findings revealed histological evidence of mandibular condyle changes due to adrenalectomy.…”

Section: Discussionsupporting

confidence: 57%

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Histologic Effects of Bilateral Adrenalectomy under the Light Microscopy on Rat Mandibular Condyle

Ülkü

Zengingul

Ketani

2009

Scholarly Research Exchange

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The aim of this study was to compare the histologic findings from the condyles of rats with the general system findings. 30 SpragueDawley adult rats were used. The rats were sacrified and their condyles and femurs were examined histologically. The rats' weight were observed weekly, their femoral height and weight, femoral mineral elements, and their daily food and water consumes were recorded. The results were analysed statistically by using SPSS (10.0). During the histologic examination of femur, the osteogenesis and calcification of the femur layers of the male/female rats in the experimental group were found to be lower than those of the ones in the control group. In addition to that, during the histological examination of condyle the level of thickness of condyle layers, the number of cellular elements, the osteogenesis and calcification seemed to be decreased for the male/female rats in the experimental group than for those in the control group. The decrease was found to be more significant for the female rats than the male rats in experimental group and it is thought that this is related to the gonad hormones. These findings emphasize that a reduction of sex hormone levels, induced by adrenalectomy, significantly influences condylar histogenesis.

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Section: Discussionsupporting

confidence: 57%

“…Glucocorticoids and mineralocorticoids play an important role in the biochemical differentiation of various organs during development. Adrenocortical hormones are known to have potent effects on bone cells [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Histologic Effects of Bilateral Adrenalectomy under the Light Microscopy on Rat Mandibular Condyle

Ülkü

Zengingul

Ketani

2009

Scholarly Research Exchange

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“…ALP is a marker of osteoblast differentiation, which is usually used to indicate the ability of osteogenesis (Zerath et al 2000). Osteocyte-like MLO-Y4 cells could produce small amounts of ALP (Bonewald 1999).…”

Section: Discussionmentioning

confidence: 99%

“…Then, what will happen to bone cells after being submitted to mechanical unloading caused by weightlessness? In the past few years, people have paid more attention to the function of osteoblasts in responding to weightlessness (Hughes-Fulford et al 2006;Saxena et al 2007;Makihira et al 2008) Scientists have found that after space flight, some changes happen in cell morphology, cell proliferation, cell cycle, cellular cytoskeleton and gene expression in osteoblasts (Landis et al, 2000;Zerath et al 2000;Hughes-Fulford 2001;Doty 2004) Also many studies have investigated the effects of simulated weightlessness on osteoblasts under ground-based condition (Rucci et al 2007;Makihira et al 2008) In recent years, osteocytes have been thought to be as main coordinator responding to mechanical loading in bone tissue (Bonewald 2006(Bonewald , 2007. Osteocytes change their structure and functions after being submitted to mechanical stimulation (Zhang et al 2006;Skerry 2008;Tan et al 2008) Then, is it right that osteocytes also might play important role in responding to mechanical unloading such as weightlessness?…”

Section: Introductionmentioning

confidence: 99%

Two-dimensional clinorotation influences cellular morphology, cytoskeleton and secretion of MLO-Y4 osteocyte-like cells

Weng

et al. 2012

Biologia

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The aim of this study was to investigate the effects of the clinostat-simulated weightlessness on biological characteristics of MLO-Y4 osteocyte-like cells. MLO-Y4 cells were incubated for 24 h, then randomly divided into 3 groups and rotated in a clinostat as a model of simulated weightlessness for 12 h, 24 h and 48 h. The morphology, cytoskeleton, and secretion of soluble molecules of MLO-Y4 cells were observed and detected. The results show that clinostat culture affects the number of dendrites/cell, cytoskeleton distribution, and secretion of nitric oxide and prostaglandin E2 in MLO-Y4 cells. These results may provide some clue to explore the cellular mechanism of bone loss caused by weightlessness.

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“…Zerath et al [33] have demonstrated that the number of total and alkaline phosphatase -positive endosteal bone cells isolated from rats after space fl ight was reduced, suggesting that osteoblast precursor cell recruitment was decreased (Fig. 7.2 ).…”

Section: Mechanisms Of Decreased Bone Formation Induced By Unloading mentioning

confidence: 97%

Bone Cell Biology in Microgravity

Carmeliet

Coenegrachts

Bouillon

2007

Biology in Space and Life on Earth

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OverviewSpace fl ight results in loss of bone mass, especially in weight -bearing bones, a condition resembling disuse osteoporosis. The general picture that emerged is that mainly bone formation is decreased, whereas bone resorption is unaltered or increased. This decrease in bone mass can be restored, but the time span for recovery exceeds the period of unloading. The pathway by which microgravity is transduced into biochemical signals has been progressively elucidated. In vitro studies using osteoblasts or their precursors show that their nuclear morphology, cytoskeletal structure and intracellular signalling cascades are altered during (simulated) microgravity, resulting in impaired differentiation of mesenchymal stem cells and osteoblasts. IntroductionTo carry out its function of mechanical integrity and its involvement in mineral homeostasis, bone is continuously remodelled. Bone remodelling is a highly complex process that is tightly regulated by local and endocrine factors and by mechanical usage. Mechanical loading plays a critical role in maintaining bone mass and strength at areas where increased force is sensed. Consequently, the architecture of bone is correlated with the mechanical stresses exerted on it, resulting in material with optimal functional design. Various models of physical exercise overloading have been shown to preserve or increase skeletal mass. Correspondingly, skeletal unloading or disuse -as in sedentary people or in diseases associated with paralysis or prolonged bed rest -are associated with bone loss and are likely to contribute in age -related osteopenia. An extreme example is the response of bone to weightlessness during space fl ight. This bone loss that develops under microgravity conditions represents the most signifi cant hindrance for long -term space travel, e.g. a fl ight to Mars, or for lengthy stays under conditions of reduced 179 Biology in Space and Life on Earth. Effects of Spacefl ight on Biological Systems. Edited by Enno Brinckmann

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Spaceflight Inhibits Bone Formation Independent of Corticosteroid Status in Growing Rats

Cited by 45 publications

References 53 publications

Histologic Effects of Bilateral Adrenalectomy under the Light Microscopy on Rat Mandibular Condyle

Histologic Effects of Bilateral Adrenalectomy under the Light Microscopy on Rat Mandibular Condyle

Two-dimensional clinorotation influences cellular morphology, cytoskeleton and secretion of MLO-Y4 osteocyte-like cells

Bone Cell Biology in Microgravity

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