Impact of SPK1 Modified ADSC on Osteogenesis of Tissue Engineered Bone / 华中科技大学学报(医学版)

ABSTRACT

Objective To investigate the impact of sphingosine kinase 1 (SPK1) modified adipose tissue-derived stromal cells(ADSC)on tissue engineered bone osteogenesis.Methods ADSC cells isolated from SD rat fat cells were divided into CON group and SPK1 group,and then the cells were respectively infected with 10 MOI CON and SPK1 lentivirus for 48 h.The infection efficiency was confirmed by using flow cytometry.Alizarin red and oil red O was used to stain the cells 14 days after ADSC infection,and osteogenic and adipogenic ability was evaluated by detecting A595nm and A490 nm.In the meantime,the activity change of alkaline phosphatase(ALP)was detected.The SD rat femoral defect model was created,and then after combining ADSC with β-TCP,the tissue engineered bone was pressed to the defect site.The repairment of bone defect was detected by X-ray in 4,6 weeks.After infection of CON and SPK1 virus,bone morphogenetic protein(BMP7)expression in ADSC of these two groups was detected.Results The infection efficiency of CON and SPK1 lentivirus was 94.4％ vs.94.9％ respectively by flow cytometry.The SPK1 protein expression level in CON group and SPK1 group was (0.73±0.10) vs.(1.29±0.17)(P＜0.05).The A value of CON and SPK1 group at 595 nm was (0.20±0.02) vs.(0.41±0.01) (P＜0.05),respectively.The A value of CON and SPK1 group at 490 nm was (0.72±0.01) vs.(0.51±0.02)(P＜0.05),respectively.The expression level of ALP in CON and SPK1 group was (1.42±-0.09) vs.(2.68±0.09) (P＜0.01),respectively.In the repairment of bone defect,high density tissue at rat bone defect was significantly larger in SPK1 group than in CON group in 4 weeks,and in 6 weeks,bone defect of SPK1 group was healed,but CON group still had defect.The expression level of BMP7 in CON and SPK1 group was (1.13±0.16) vs.(4.46±0.23)(P＜0.05),respectively,48 h after infection.Conclusion SPK1 modified ADSC has an enhanced osteogenesis ability in vitro and in vivo,which was related to the activation of BMP7.