ABSTRACT
Objective To study the influence of irradiation on the osteoblast function by the gene expression changes of RANKL and OPG.Methods Bone marrow stromal cells were induced to develop into early and mature osteoblasts in vitro.The characterization of osteoblasts was indentified by ALP staining.The RANKL and OPG mRNA levels in early and mature osteoblasts, which exposed to 0 -4 Gy radiation were determined by RT-PCR.Results Bone marrow stromal cells had been induced to early and mature osteoblasts by osteoblast differentiation medium in vitro.In early stage of osteoblast, RANKL mRNA expression levels treated with 1Gy irradiation was 2.83-fold higher than those other irradiation dosage groups.The RANKL mRNA expression levels of each group in early stage of osteoblasts were significantly higher than those in the mature counterpart ( t = 8.34 - 103.57, P ＜ 0.05 ).The ratio of RANKL/OPG mRNA was obviously greater in early osteoblast compared with the mature cells ( t = 2.84 - 20.99, P ＜0.05 ), and it was the highest in 1Gy irradiation treated early osteoblast.Conclusions Radiation exposure of the early osteoblasts promotes osteoclasts function and results in the bone loss.
ABSTRACT
Objective Cancer radio-therapy may induce bone damage of the patients.collagen type I gene expressions in osteoblast after radiation indicates the influence of radiation on the function of early and late osteoblast.Methods Bone marrow stromal cells were differentiated into osteoblasts in vitro.and the characteristics was indentified.The collagen type I expressions in early and late stage osteoblasts exposed to 1～4Gy radiation were examined by RT-PCR.Results Compared to control group,collagen type I gene expressions increased in early osteoblast after 1～3 Gy radiation (P＜0.05),while the gene expressions in late osteoblast that cultured 10 days decreased.Collagen type I gene expression in late stage ostoblast after 4 Gy irradiation was greatly higher than that in early stage osteoblast (P＜0.01).Conclusion After 1～3 Gy irradiation,the collagen type I expression in early osteoblast was enhanced,indicating the increased ability of bone formation.The exposure to 1～3 Gy decreased collagen type I expression in late osteoblast and weakened the ability of bone formation.The result of high expression of collagen type I in late osteoblast after 4 Gy irradiation may be the manifestation of compensatory function.