Trap17 dating


Oc/TV) and osteoclast surface relative to bone surface (Oc.S/BS) were estimated by point counting in a squared grid within 500 μm from the epiphyseal/metaphyseal border (EMB) at TEM micrographs.Moreover, Ovx-D rats presented a tendency toward increased TRAP m RNA expression in osteocytes, questioning the hypothesis of endocytosis being the mechanism enhancing TRAP protein expression and enzyme activity in osteoblasts and osteocytes in these rats.To further address this question, rats healing from nutritionally induced low-phosphate and vitamin D-deficiency rickets (experimental rickets) were analyzed as a model of increased osteoclast activity [].Osteoblasts and osteocytes close to intracortical remodeling sites and bone surfaces demonstrated TRAP, most prominently in cancellous bone and osteocytes.Intracellular TRAP was located to electron-dense vesicles with similar morphology in both cell types.Longitudinal sections from the tibial diaphysis (Ovx-D/sham) and femoral diaphysis (experimental rickets) were subjected to hybridization following our established protocol [ osteocytes were quantified in cortical bone within 4–10 mm from the proximal EMB by point counting in a squared grid.

The means were calculated for each animal with respect to the parameters above and used for comparison between the groups.This theory is supported by cell culture studies reporting that osteoblast-like cells are able to engulf osteoclastic TRAP and inactivate the enzyme, suggesting that this could control the enzyme activity and prevent further degradation of matrix constituents [] have demonstrated enlarged osteocyte lacunae and canaliculi and increased amounts of TRAP and cathepsin K in osteocytes in lactating mice, suggesting that osteocytes are able to remodel their own matrix environment through osteoclast-like mechanisms under specific conditions.To increase the knowledge of TRAP in osteoblasts and osteocytes, we analyzed two experimental rat models with disturbed bone metabolism to investigate whether changes in osteoclast activity could alter TRAP protein expression and enzyme activity in osteoblasts and/or osteocytes in vivo.Tartrate-resistant acid phosphatase (TRAP) is known as an osteoclast marker, but osteoblasts and osteocytes in the vicinity of bone remodeling sites also express TRAP.Cell culture studies suggest that osteoblasts endocytose osteoclastic TRAP for inactivation.Micrographs from 10–20 osteoblasts and osteocytes were randomly sampled from each animal. Longitudinal tibia mid-diaphyseal sections from Ovx-D and sham animals at the same bone level were subjected to conventional hematoxylin–eosin–saffron (HES) staining.

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