Effects Of Shock Wave On C-Fos,c-Jun Protein Expression In Human Mesenchymal Stem Cells

Mesenchymal Stem cells (MSCs) are multipotent stem cells derived from mesoderm, possessing potent proliferative capacity and self- renewal and pluripotent. MSCs can differentiate into osteocytes, adipocytes , muscle cells ,liver cells, neuron-like cells , neuroglial cells and so on.. MSCs have some advantages, including drawing the materials easily and slightly injury, multiple amplify- cation easy in vitro, no ethical matters and immune rejection and differentiation easy. For this reason, MSCs have been widely used as vector cells in tissue engineering. Therefore the applications of hMSCs in these areas have drawn great attention and have been widely explored in clinical and preclinical studies.At first,Extracorporeal Shock Wave Therapy(ESWT) was used to cure the calculus of urinary system.Then people found that it also can cure the ununion and delayed union of bone ,the avascular necrosis of the femoral head and the chronic injury of locomotor system,what has got a good curative effect.Many researches indicate that physical stimulation can promotes the proliferation and differentiation of hMSCs,such as shear stress, stretch stress,and so on.But the researches about ESW are not as many as those.Now we have learned that ESW ,as a kind of physical stimulation,can promote differentiation of hMSCs into osteoblast, induce cell proliferation, increase alkaline phosphatase activity, type I collagen protein expression and osteocalcin synthesis, and ultimately induce bone formation.But this process does not happen spontaneously.It involves many kinds of signaling pathway,and the mitogen-activated protein kinase (MAPK) signaling pathway is one of the most important pathway. The MAPK is one of the major kinase families that regulate cells by transducing extracellular signals into cellular responses。Three important members of this family are the extracellular signal-regulated kinase (ERK), p38,and c-Jun N-terminal kinase (JNK).They participate the movement, apoptosis,differentiation and proliferation of cells.MAPK pathway can be activated by the source of stimulation signal, including mechanical stimulation,cytokines,growth factors,hormones,and so on. After being activated,it can regulate gene transcription and then participate in physiological processes, such as apoptosis, differentiation,proliferation.The latest researches manifest that MAPK relates to the signal conduction of osteoblasts'differentiation and proliferation,what make it highly concerned.Activated protein -1 (AP-1) is a intersection of cell signaling pathways in the nucleus. As the one of substrates of MAPK signaling pathway, it composite by Jun and Fos family members. It participates the regulation of bone formation and osteoclasia,and has an interaction with many kinds of growth factors.The promoter region of many bone metabolism related gene has AP-1,such as osteocalcin, TypeⅠCollagen,matrix metalloproteinase matrilysin,ALP. As one of substrates of MAPK pathway ,AP-1 is activated by phosphorylation.Its activation involves several mechanisms that can be summarize to two patterns: phosphorylated or total AP-1 protein levels increased.There are no researches indicating that if ESW makes phosphorylated or total AP-1 protein levels changed by MAPK pathway.The intervention research of ESW induce MSCs are less. In this respect, this experiment focused on human mesenchymal stem cells (hMSCs) what are derived from adult bone marrow. The cells were isolated and cultured in vitro by density centrifugal and anchoring screening. Then observe the morphology under microscope, count the amount of cells and draw cell growth curve.And investigating the change of phosphorylated and total AP-1 protein levels after a treatment of an optimal dose of shock wave,and exploring the mechanism of differentiation of MSCs into osteoblast induced by ESWObjective To investigate the expression of c-Fos,c-Jun protein in human Mesenchymal Stem Cells influenced by shock wave,and explore the mechanism of differentiation of MSCs into osteoblast induced by ESW.Methods The hMSCs derived from the bone marrow pool collected from healthy human volunteers.The cells were isolated and cultured in vitro by density centrifugal and anchoring screening.By means of western-blotting, the activations of c-Fos and c-Jun were observed at different time points (5min,15min,30min,1h,2h) after a treatment of an optimal dose of shock wave(8.5 kV,120 times). Results After induced by ESW, the c-Fos phosphorylation level begins to increase, and it is maximal at 30min which is 2.56-fold (P<0.05) compared with the average level in control groups.Then the level decreased,there are no obvious changes comepared with control groups at 2h. The c-Fos level is not increased appearently by ESW (P >0.05).After induced by ESW, the c-Jun phosphorylation level begins to increase, and it is maximal at 15min which is 1.68-fold (P<0.05) compared with the average level in control groups.Then the level decreased. Two hours later,the level is still higher than the control groups(P<0.05).The c-Jun level is not increased appearently by ESW (P >0.05).Conclusion Following the treatment of shock wave, the activations of c-Fos and c-Jun in Mesenchymal Stem Cells increased and changed at different temporal pattern. There is a probability that ESW promotes differentiation of MSCs into osteoblast by influencing the activations of c-Fos and c-Jun protein,and then curing the diseases of skeletal system.