title: Irradiation alters the differentiation potential of bone marrow mesenchymal stem cells.
abstract: Bone injury following radiotherapy has been confirmed by epidemiological and animal studies. However, the underlying mechanism remains to be elucidated and no preventive or curative solution has been identified for this bone loss. The present study aimed to investigate the irradiation‑altered osteogenesis and adipogenesis of bone marrow mesenchymal stem cells (BMSCs). BMSCs were derived and exposed to γ‑irradiation at doses of 0, 0.25, 0.5, 1, 2, 5 and 10 Gy. Cell viability was assessed using a 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5 diphenyl tetrazolium bromide assay, and clonal expansion in vitro was detected by colony forming unit assessment. The osteogenic differentiation ability was demonstrated by alkaline phosphatase (ALP) activity, ALP staining and mineralization alizarin red staining, and the adipogenic differentiation ability was determined using Oil O red staining. The osteogenesis‑associated genes, RUNX2, ALP, osteocalcin (OCN) and adipogenesis‑associated genes, PPAR‑γ and C/EBPα, were detected using reverse transcription‑quantitative polymerase chain reaction analyses. The protein expression levels of RUNX2, ALP and PPAR‑γ were detected using western blotting. Compared with the control, significant decreases in the proliferation, ALP activity and mineralization ability of the BMSCs were observed in the γ‑irradiation group, with a high level of correlation with the exposure dose. However, no significant changes were observed in the area of Oil red O positive staining. The mRNA levels of RUNX2, ALP and OCN were decreased (P<0.05), however, no significant changes were observed in the levels of C/EBPα and PPAR‑γ. The protein expression levels of RUNX2 and ALP were decreased in the irradiated BMSCs, however, no significant difference was observed in the protein expression of PPAR‑γ. Irradiation inhibited the osteogenic and adipogenic ability of the BMSCs, and the osteogenic differentiation was decreased. The results of the present study provided evidence to assist in further elucidating radiotherapy‑associated side effects on the skeleton.
authors.affiliation: Department of Radiation Protection, Institute of Radiation Medicine, Fudan University, Shanghai 200032, P.R. China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Radiation Protection, Institute of Radiation Medicine, Fudan University, Shanghai 200032, P.R. China.
authors.forename: Guoying
authors.initials: G
authors.lastname: Zhu
authors.affiliation: Department of Radiation Protection, Institute of Radiation Medicine, Fudan University, Shanghai 200032, P.R. China.
authors.forename: Jianping
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Radiation Protection, Institute of Radiation Medicine, Fudan University, Shanghai 200032, P.R. China.
authors.forename: Junxiang
authors.initials: J
authors.lastname: Chen
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western; D001854:Bone Marrow Cells / Q000166:cytology* / Q000528:radiation effects*; D002113:Calcification, Physiologic / Q000528:radiation effects; D002453:Cell Cycle / Q000528:radiation effects; D002454:Cell Differentiation / Q000528:radiation effects*; D002462:Cell Membrane / Q000378:metabolism / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism; D005720:Gamma Rays; D005786:Gene Expression Regulation / Q000528:radiation effects; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000201:enzymology / Q000528:radiation effects*; D015675:Osteocalcin / Q000378:metabolism; D047495:PPAR gamma / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D013194:Staining and Labeling
chemical_list: D015415:Biomarkers; D050659:Core Binding Factor Alpha 1 Subunit; D047495:PPAR gamma; D012333:RNA, Messenger; D015675:Osteocalcin; D000469:Alkaline Phosphatase