Objective:To study the effects of BMP-7 gene transfected bone marrow mesenchymal stem cells(MSCs)on callus acceleration in rat mandibular distraction osteogenesis.Methods:Forty-eight adult male SD rats were randomly divided into experimental and control groups.MSCs were obtained from individual rat and transfected by pEGF-P-BMP7 for the 24 experimental rats and by the empty vector pEGFP-N1 for the 24 control rats.The rats were underwent right mandibular distraction.1?106/100 ?l BMP-7 gene transfected cells in 10 ?l of normal saline were injected into the distraction gap in each experimental rat,while the same number of empty vector transfected cells in each control rat.The distracted mandibles were harvested 2,4,and 8 weeks respectively after cell injection and evaluated by radiological,histological and histomorphometric analysis.Results:Radiological and histological examinations showed that more new bone was formed in experimental group than in control.Histomorphometric analysis also demonstrated that both new bone volume(NBV1 and NBV2)and the thickness of new trabeculae(TNT)were significantly higher in experimental rats than those in control(P

Objective To investigate the effect of phenylephrine on the morphology and the expression level of Nampt mRNA in the irradiated osteoblasts of the rats,and to clarify the possible protective effects of phenylephrine on this injury.Methods The osteoblasts cultured by conventional tissue were randomly divided into control group, phenylephrine group,simple irradiation group,and phenylephrine+irradiation group.The cells in phenylephrine group were treated with 100 mmol· L-1 phenylephrine 30 min before irradiation.The cells in simple irradiation group were irradiated with 8 Gy X-ray.The osteoblasts were observed by microscope and were collected at the time points of 8,16,32 and 64 h after irradiation.The Nampt mRNA expression level in osteoblasts was examined by RT-PCR.Results There was no obviously morphological and number changes of osteoblasts in phenylephrine group compared with control group.The osteoblasts in simple irradiation group were atrophied,especially at 8 h;the number of osteoblasts in simple irradiation group was 0.82,0.37,0.24 and 0.21 times as control group respectively at 8,16,32 and 64 h. Atrophy of osteoblasts was alleviated in phenylephrine+irradiation group;at 8, 16,32 and 64 h,the number of osteoblasts was 0.91,0.83,0.72 and 0.75 times as control group,and was 1.09,2.24,3.00 and 3.60 times as simple irradiation group. The expression level of Nampt mRNA in the osteoblasts in simple irradiation group was reduced compared with control group (P < 0.01) at 8, 16, 32 and 64 h.There were significant differernces of the expression levels of Nampt mRNA in the osteoblasts between phenylephrine+irradiation group and control group (P < 0.01),and there were significant differernces between phenylephrine + irradiation group and simple irradiation group (P < 0.01 ) at the different time points. Conclusion Phenylephrine could reduce the atrophy of osteoblasts in the rats induced by irradiation and up-regulate the expression level of Nampt mRNA.Its protective effect on irradiated injury may be related to the up-regulation of the expression level of Nampt mRNA.