Effect Of BDNF On Proliferation And Apoptosis Of Osteoblast In Fracture Healing

BDNF is an important member of neurotrophic family, a lot of researches have find that highly BDNF and its receptors are expressed in fracture callus tissue. Neurotrophic family may play an important role in fracture healing progress, however the mechanism remains unclear. Delayed union and nonunion is serious problem in clinical orthopedics, osteoblast is the most important cell type during fracture healing, the research of effect of BDNF on osteoblasts is vital to understand the mechanism of fracture healing progress.Objective:To investigate the effect of BDNF on cell proliferation and apoptosis. Methods:First we studied the methods of isolated culture and purification of neonatal mice calvarial osteoblasts. We analyzed ALP mRNA expression using RT-PCR. The viability of cell was detected by MTT, cell apoptosis was detected by annexin V-FITC/PI staining, the expression of bcl-2 and bax was detected by western blot.Results:(1)Primarily cultured calvarial osteoblasts growed fast in vitro environment. After 24h of cell culture, most cells adhered to the culture plat. The bottom was filled with cells after 7 days. Passage cells growed even faster than the primary osteoblasts. We discovered high expression of ALP in cultured cells using RT-PCR, which identified the cultured cells as osteoblasts.(2)BDNF (higher than 50ng/ml) could significantly promote cell proliferating.(3)BDNF (higher than 50ng/ml) could save cultured cells from apoptosis, and decrease the expression of bax. BDNF could increase the expression of bcl-2 on the contrary.Conclusion:As to the primary isolation of osteoblasts from new born mice, enzymatically released osteoblasts from new born mouse is a reliable, efficient and effective method. BDNF (50ng/ml) can promote cell proliferation and prevent cell apoptosis.