title: Insulin-like growth factor I regulates apoptosis in condylar cartilage.
abstract: Endogenous insulin-like growth factor-I (IGF-I) is known to affect the growth and development of condylar cartilage. However, the critical effect of IGF-I on cell survival is still unknown. We hypothesized that endogenous IGF-I could regulate the survival of cells of the mandibular condylar cartilage. Mandibular condyles dissected from 12-day-old rats were cultured for 1, 3, and 5 days in medium containing antisense oligodeoxynucleotide (AS-ODN) for IGF-I. Real-time RT-PCR analysis showed that the levels of IGF-I and IGF binding protein (IGFBP)3 mRNAs in the AS-ODN group were significantly decreased. After 3 days' culture, the number of necrotic cells was observed in the undifferentiated mesenchymal cell layer. These cells were TUNEL-positive and confirmed to be apoptotic by electron microscopic observation. Immunoblotting revealed that expression of cleaved caspase3 was increased with AS-ODN. These results may suggest that the cells in the undifferentiated mesenchymal cell layer of the mandibular condyle require IGF-I for survival.
authors.affiliation: Department of Maxillofacial Restoration, Division of Maxillofacial/Neck Reconstruction, Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yokota
authors.forename: H
authors.initials: H
authors.lastname: Shimokawa
authors.forename: S
authors.initials: S
authors.lastname: Shibata
authors.forename: K
authors.initials: K
authors.lastname: Itoh
authors.forename: Y
authors.initials: Y
authors.lastname: Baba
authors.forename: K
authors.initials: K
authors.lastname: Ohya
authors.forename: K
authors.initials: K
authors.lastname: Ohyama
authors.forename: S
authors.initials: S
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002356:Cartilage / Q000166:cytology*; D053148:Caspase 3 / Q000032:analysis; D002454:Cell Differentiation; D002470:Cell Survival / Q000502:physiology; D015151:Immunoblotting; D020287:In Situ Nick-End Labeling; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000032:analysis; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000502:physiology*; D008335:Mandibular Condyle / Q000166:cytology*; D008648:Mesoderm / Q000166:cytology; D008854:Microscopy, Electron; D009336:Necrosis; D020319:Oligodeoxyribonucleotides, Antisense / Q000494:pharmacology; D009924:Organ Culture Techniques; D016133:Polymerase Chain Reaction; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D018972:Insulin-Like Growth Factor Binding Protein 3; D020319:Oligodeoxyribonucleotides, Antisense; D007334:Insulin-Like Growth Factor I; D053148:Caspase 3