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Objective To evaluate the effect of gamma irradiation on the proliferation,differentiation,and mineralization of murine osteoblastic cells,and to investigate the related molecular mechanism.Methods Osteoblastic cells were irradiated by different doses (0,0.5,1.0,2.0,5.0 Gy)of 137Cs γ-rays.Cell morphology was observed with a microscopy,cell viability was analyzed by MTT assay,and ALP activity was analyzed by the methods of enzyme histochemistry and PNPP.Meanwhile,gene expressions of ALP,osteocalcin (OC),collagen Ⅰ,osteoprotegerin (OPG) and receptor activator of nuclear factor-kB ligand (RANKL) were measured by semi-quantified RT-PCR.Results Cell viability decreased with the radiation doses over 1.0 Gy ( t =6.197 - 18.677,P ＜ 0.05 ).After radiation with a dose over 2.0 Gy,the cell number and the junctions of cell protrusions decreased,the cells had low refractivity and the activity and mineralization ability of ALP were also inhibited ( t =2.790 -2l.374,P ＜0.05).In addition,the expressions of ALP and OC mRNA were down-regulated significantly (t =3.563 -16.508,P ＜ 0.05) when the radiation dose was higher than 0.5 Gy,and the expressions of OPG,OPG/RANKL mRNA were down-regulated ( t =12.942,4.954,P ＜ 0.05 ) at 5 Gy.But the expressions of collagen Ⅰ and RANKL mRNA were not affected by irradiation.Conclusions The osteoblastic cells were significantly influenced by γ-irradiation,including morphological changes,inhibition of cell proliferation,differentiation and mineralization ability. Meanwhile,mRNA expressions of ALP and OC were downregulated.OPG/RANKL may be a main pathway of osteoblastic cell damage under high dose radiation.
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Objective To explore the feasibility of using glycophorin A somatic mutation in peripheral erythrocytes,in order to evaluate the cancer risk of occupational medical exposure to ionizing radiation.Methods Totally 336 medical radiation workers were recruited as three groups (general radiation group,computer tomography group,intervention and radiation treatment group) and 112 healthy adults were selected as control by using stratified random cluster sampling method,where 176 medicalradiation workers and 58 health controls had a MN-heterozygous type.The erythrocytes were fixed and bound with fluorescent-labeled monoclonal antibody,and the glycophorin A somatic mutation frequency was assayed by a modified BR6-1W1 method using a FACScan flow cytometer.The individual susceptibility to radiation was investigated using micronuclei test and 3-Aminobenzamide index test.Results The GPA somatic mutation frequency of medical-radiation workers was significantly higher than that of healthy control ( t =2.29 - 11.48,P ＜ 0.05 ).In particular,the NO GPA aberration frequency of interventional radiology workers was much higher than that of the general medical diagnostic workers (t =2.01,P ＜ 0.05).In addition,the NO GPA variant frequency changed significantly with the years of radiation service,cumulative doses,and 3AB index.However,the NN GPA variant frequency was only associated with the years of radiation service,and no significant correlations were found between NN GPA variant frequency and cumulative dose of radiation exposure or 3AB index. Conclusions GPA mutation frequency,especially NO GPA mutation frequency could be used as a sensitive biomarker to predict the DNA damage and individual susceptibility for the population exposed to professional low-dose ionizing radiation.
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Objective To investigate the differences in function and collagen type I(COL-1) expression of cultured human ostoblastic cells between different age donors in vitro. Methods Human osteoblasts from different age donors(
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Human osteoblasts from donors of different age (≤5, 30-40, 50-60, ≥70) groups were isolated and cultured. Osteoprotegerin (OPG) and osteoclast differentiation factor (ODF) mRNA expressions were assayed by RT-PCR when the osteoblasts in the second passage were cultured for 14 days. Results showed that human osteoblasts from different age groups expressed OPG and ODF mRNA. Quantity of OPG mRNA and ODF mRNA expressions was correlated to donor′s age.