The Differential Effect Of BFGF And SDF-1 Pretreatment On BMMSCs Osteogenic Differentiation Potentials

Background and ObjectiveThe use of in situ tissue engineering to repair the defect of periodontal tissue has become a new hotspot in the field of periodontal tissue regeneration in which the choice of cytokines is the key point.Stromal cell-derived factor-1(SDF-1)and basic fibroblast growth factor(bFGF)have the ability to promote the recruitment and proliferation of stem cells,thus,both are potential candidates for application in in situ periodontal/bone tissue engineering.As we all knew,cytokines,chemokines and adhesion molecules could promote stem cell recruitment,and they could be used to restore the defect tissue,the recruited and proliferated stem cells need osteogenic differentiation for their roles in periodontal regeneration.Therefore,differential effect of different cytokine pretreatment on osteogenic differentiation of stem cells may be an important factor for the choice of cytokines.Here,osteogenic differentiation capability of BMMSCs(ST2 cell line)pretreated separately with bFGF and SDF-1 was compared.Materials and MethodsST2 were pretreated separately in maintenance medium(control),maintenance medium with 20 ng/ml bFGF(Test 1)and maintenance medium with 200 ng/ml SDF-1(Test 2)for 48 hours.Then,each group of cells was further cultured in the ostogenic induction medium for 3,7 and 14 days.The gene and protein expressions of ALP?BSP and Runx-2 were detected by RT-PCR and Western Blot.The formation of calcium nodules was observed after 28 days.ResultsTest 1:On day 3,expressions of ALP and Runx-2 mRNA and ALP protein were significantly lower than control;On day 7,expressions of ALP?BSP and Runx-2 mRNA and ALP protein were significantly higher than control;On day 14 and 28,there was no significant difference in osteogenic markers between Test 1 and control.Test 2?On day 3,expression of ALP mRNA and protein was significantly lower,while Runx-2 protein higher,than control;On day 7,only ALP protein expression was significantly increased compared with control;On day 14 and 28,there was not significant difference in osteogenic markers between Test 2 and control.Comparision of Test 1 and Test 2:Expressions of ALP mRNA on day 3 and BSP and Runx-2 mRNA on day 7 in Test 1 were significantly higher than that in Test 2;Expressions of Runx-2 mRNA and ALP and Runx-2 protein on day 3 in Test 2 were higher than those in Test 1.ConclusionbFGF and SDF-1 pretreatment inhibits at early period and promotes in the medium phase osteogenic differentiation of BMMSCs during osteogenic induction,of which bFGF behaves more abviously on these two aspects.