[Effects of 0.5 Gy X-ray radiation on the profile of gene expression in MC3T3-E1 osteoblasts]

Objective: To investigate the molecular mechanism of low-dose X-ray irradiation on osteoblasts by detecting the gene expression profiles of osteoblasts radiated with 0.5 Gy X-ray. Methods: Microarray analyses to value the changes of gene expression of MC3T3-E1 osteoblasts after 0.5 Gy X-ray irradiation were conducted.The end points included modulation of key markers, and pathway and gene ontology through transcriptomic profiling and bioinformatics analysis. Several major genes during osteoblasts differentiation were selected for Real-time PCR analysis. Results: 1 412 differentially expressed transcripts were identified between the radiated group and control group. Among the identified genes, 559 transcripts were up-regulated and 853 transcripts were down-regulated after irradiation.Real-time PCR analysis indicated that the mRNA expressions of Bglap-rs1, Col1a2, Tgf-β1, Lrp5, Dvl1, Map4k5 were apparently higher than that of the controls (P<0.01), whereas the Id2 and Dkk1 expression decreased under the same condition(P<0.01). Western-blot analysis indicated TGF-β1 and Lrp-5 protein expression increased and Dkk1 expression decreased(P<0.05). Pathway analysis and gene ontology analysis revealed that focal adhesion, extracellular signaling, cytoskeletal protein binding, Wnt signal pathway, IκB /NF-κB signal pathway and growth factor receptors activities. Conclusions: Low-dose X-ray radiation promoted osteoblasts differentiation in which focal adhesion, extracellular signaling, cytoskeletal protein binding, Wnt signal pathway, IκB /NF-κB signal pathway and growth factor activities might be involved.