title: Lactoferrin inhibits apoptosis through insulin-like growth factor I in primary rat osteoblasts.
abstract: OBJECTIVE
  Excessive apoptosis of osteoblasts is the major cause of low bone mass, and bovine lactoferrin (bLF), an iron-binding glycoprotein, might protect osteoblastic cells from apoptosis induced by serum withdrawal. The aim of this study was to elucidate the mechanisms underlying the anti-apoptotic action of bLF in rat osteoblasts in vitro.
  
  
  METHODS
  Primary rat osteoblasts were incubated in the presence of varying concentrations of bLF for 24 h. The expression of insulin-like growth factor I (IGF-I) and IGF-I receptor (IGF-IR) was measured uisng RT-PCR and Western blotting. Cell apoptosis was examined with flow cytometry. siRNAs targeting IGF-I was used in this study.
  
  
  RESULTS
  Treatment of bLF (0.1-1000 μg/mL) dose-dependently increased the expression of IGF-I and IGF-IR in the osteoblasts. Treatment with bLF (10, 100 μg/mL) markedly inhibited the osteoblast apoptosis (with the rate of total apoptosis of 70% at 10 μg/mL), but the high concentration of bLF (1000 μg/mL) significantly promoted the osteoblast apoptosis. Knockdown of the IGF-I gene in osteoblasts with siRNA markedly increased the osteoblast apoptosis.
  
  
  CONCLUSIONS
  Lactoferrin (10 and 100 μg/mL) effectively inhibits apoptosis of primary rat osteoblasts by upregulating IGF-I expression.
authors.affiliation: 1] Fujian Provincial Hospital, Fuzhou 350001, China [2] Provincial Clinical Medical College of Fujian Medical University, Fuzhou 350004, China.
authors.forename: Jian-ming
authors.initials: JM
authors.lastname: Hou
authors.affiliation: Provincial Clinical Medical College of Fujian Medical University, Fuzhou 350004, China.
authors.forename: En-yu
authors.initials: EY
authors.lastname: Chen
authors.affiliation: 1] Fujian Provincial Hospital, Fuzhou 350001, China [2] Provincial Clinical Medical College of Fujian Medical University, Fuzhou 350004, China.
authors.forename: Shi-chao
authors.initials: SC
authors.lastname: Wei
authors.affiliation: 1] Fujian Provincial Hospital, Fuzhou 350001, China [2] Provincial Clinical Medical College of Fujian Medical University, Fuzhou 350004, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Lin
authors.affiliation: 1] Fujian Provincial Hospital, Fuzhou 350001, China [2] Provincial Clinical Medical College of Fujian Medical University, Fuzhou 350004, China.
authors.forename: Qing-ming
authors.initials: QM
authors.lastname: Lin
authors.affiliation: 1] Fujian Provincial Hospital, Fuzhou 350001, China [2] Provincial Clinical Medical College of Fujian Medical University, Fuzhou 350004, China.
authors.forename: Xu-hua
authors.initials: XH
authors.lastname: Lan
authors.affiliation: 1] Fujian Provincial Hospital, Fuzhou 350001, China [2] Provincial Clinical Medical College of Fujian Medical University, Fuzhou 350004, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Xue
authors.affiliation: Provincial Clinical Medical College of Fujian Medical University, Fuzhou 350004, China.
authors.forename: Man
authors.initials: M
authors.lastname: Wu
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects*; D002417:Cattle; D002478:Cells, Cultured; D024042:Collagen Type I / Q000378:metabolism; D019610:Cytoprotection; D004305:Dose-Response Relationship, Drug; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism*; D007781:Lactoferrin / Q000494:pharmacology*; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D061251:Primary Cell Culture; D034622:RNA Interference; D017207:Rats, Sprague-Dawley; D017526:Receptor, IGF Type 1 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014162:Transfection; D015854:Up-Regulation
chemical_list: D024042:Collagen Type I; C548904:insulin-like growth factor-1, rat; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1; D000469:Alkaline Phosphatase; D007781:Lactoferrin