Insulin-like growth factor-I (IGF-I) and IGF-I receptor (IGF-IR) immunoreactivity in normal and osteopetrotic (toothless, tl/tl) rat tibia.
Insulin-like growth factor-I (IGF-I) plays a major role in regulating cell growth. This study examined the immunohistochemical distribution of IGF-I and IGF-I receptor (IGF-IR) in tibias from normal and osteopetrotic (toothless, tl/tl) rats, following treatment with colony stimulating factor-1 (CSF-1). In normal rats, immunoreactivity for IGF-I and IGF-IR was detected in cells of the articular and epiphyseal cartilage, secondary ossification centres, zones of resting and proliferating chondrocytes and bone marrow. Bone marrow cells immunoreactive for IGF-I and IGF-IR were significantly reduced in the tl/tl rat (p < 0.001) compared with normal animals. Treatment of tl/tl rats with CSF-1 increased immunoreactivity for IGF-I and IGF-IR in bone marrow cells as well as the number of TRAP positive osteoclasts. This increase was the result of recruitment of a range of hematopoietic cell types, including eosinophils, polymorphs and a substantial number of monocyte-like cells demonstrating strong immunoreactivity to IGF-I/IGF-IR. The differences in relative immunoreactivity for IGF-I/IGF-IR by bone marrow cells in untreated and CSF-1-treated tl/tl rats indicate a CSF-1-dependent recruitment of cells bearing surface IGF-IRs which may be mediated by an increase in local or systemic IGF-I.
Joseph
B K
BK
School of Dentistry, University of Queensland, Brisbane, Australia.
Marks
S C
SC
Hume
D A
DA
Waters
M J
MJ
Symons
A L
AL
D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D001854:Bone Marrow Cells / Q000737:chemistry / Q000276:immunology; D002358:Cartilage, Articular / Q000737:chemistry / Q000276:immunology; D007150:Immunohistochemistry; D007334:Insulin-Like Growth Factor I / Q000276:immunology*; D007527:Isoenzymes / Q000378:metabolism; D016173:Macrophage Colony-Stimulating Factor / Q000627:therapeutic use; D009000:Monocytes / Q000201:enzymology; D010010:Osteoclasts / Q000201:enzymology; D010022:Osteopetrosis / Q000276:immunology / Q000378:metabolism*; D051381:Rats; D011922:Rats, Mutant Strains; D017526:Receptor, IGF Type 1 / Q000276:immunology*; D000071681:Tartrate-Resistant Acid Phosphatase; D013977:Tibia / Q000737:chemistry* / Q000473:pathology
D015415:Biomarkers; D007527:Isoenzymes; D007334:Insulin-Like Growth Factor I; D016173:Macrophage Colony-Stimulating Factor; D017526:Receptor, IGF Type 1; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase