Abstract
The toothless (tl) osteopetrotic mutation in the rat is characterized by generalized skeletal sclerosis, a severe reduction in the numbers of osteoclasts, monocytes, and macrophages, and absence of tooth eruption. Studies examining gene expression in bone-derived cells of tl rats and their normal littermates have shown that genes related to osteoblast function are aberrantly expressed in tl rats compared to normal littemates. We have previously shown that exogenous administration of colony stimulating factor-1 (CSF-1) to tl rats results in a dramatic reduction of the skeletal sclerosis and significant increases in the number of osteoclasts. Thus, we examined the effects of CSF-1 on osteoblast and osteoclast gene expression in tl rats as demonstrated by Northern blot analysis. While osteoblast-related gene expression as reflected by mRNA levels of alkaline phosphatase, osteocalcin, osteopontin, and type I collagen was normalized, osteoclast-related gene expression, as reflected by mRNA levels of carbonic anhydrase II and tartrate-resistant adenosine triphosphatase, remained significantly lower in CSF-1-treated tl rats compared to untreated normal littermates. Since previous studies have not demonstrated the CSF-1 receptor on osteoblasts, these results suggest that osteoblast abnormalities in tl rats are an effect of the osteopetrotic condition rather than the cause of the disease.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adenosine Diphosphate / metabolism
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Alkaline Phosphatase / genetics
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Alkaline Phosphatase / metabolism
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Animals
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Blotting, Northern
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Bone and Bones / diagnostic imaging
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Bone and Bones / drug effects
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Carbonic Anhydrases / genetics
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Carbonic Anhydrases / metabolism
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Collagen / genetics
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Collagen / metabolism
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Disease Models, Animal
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Gene Expression Regulation / drug effects*
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Gene Expression Regulation / genetics
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Histones / genetics
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Histones / metabolism
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Macrophage Colony-Stimulating Factor / administration & dosage
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Macrophage Colony-Stimulating Factor / pharmacology*
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Macrophage Colony-Stimulating Factor / therapeutic use
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Macrophages / cytology
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Macrophages / drug effects
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Monocytes / cytology
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Monocytes / drug effects
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Osteoblasts / cytology
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Osteoblasts / drug effects*
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Osteocalcin / genetics
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Osteocalcin / metabolism
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Osteoclasts / cytology
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Osteoclasts / drug effects*
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Osteopetrosis / genetics*
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Osteopetrosis / pathology
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Osteopetrosis / physiopathology
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Osteopontin
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RNA, Messenger / metabolism
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Radiography
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Rats
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Receptor, Macrophage Colony-Stimulating Factor / drug effects
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Receptor, Macrophage Colony-Stimulating Factor / metabolism
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Sialoglycoproteins / genetics
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Sialoglycoproteins / metabolism
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Tibia / diagnostic imaging
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Tibia / drug effects
Substances
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Histones
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RNA, Messenger
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Sialoglycoproteins
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Spp1 protein, rat
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Osteocalcin
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Osteopontin
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Adenosine Diphosphate
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Macrophage Colony-Stimulating Factor
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Collagen
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Receptor, Macrophage Colony-Stimulating Factor
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Alkaline Phosphatase
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Carbonic Anhydrases