| Bone marrow derived mesenchymal stem cells (MSCs) are the cells with thepotential of proliferation and multiple-directional differentiation. In specificenvironmental conditions, MSCs can proliferate and differentiate into a variety of cells.MSCs have the properties of chemotaxis, which can be mobilized and migrate inresponse to inflammation or tissue damage (including tumors). MSCs play an importantrole in tissue reparation and regeneration, which make them the seed cells of clinicalcell therapy and the most widely used stem cell type.Cells and tissues in the organism are in a complex mechanical microenvironment.In the process MSCs move out of the bone marrow into the peripheral blood, they aresubujected to blood flow shear stress and tensile strain. Mechanical factors may regulatephysiological and pathological processes of living cells. There are a number of reportsillustrated the impact of mechanical stimulation on the proliferation, phenotype anddifferentiation in MSCs. Further research on the molecular mechanism is carrying on.But so far, the mechanical factors affect the migration behavior of MSCs and itsmolecular mechanism is still poorly understood. This paper attempts to reveal theinfluence and molecules mechanism of mechanical stretch on the migration behavior ofrat MSCs (rat of MSCs, rMSCs were). In this study we use uniaxial tensile loadingdevice to impose different conditions of mechanical stretch (frequency:1Hz, magnitude:5%to15%, stretch time:4~12h) on rMSCs cells. Transwell and scratching methodwas used to detect the migration of rMSCs and the expression of matrixmetallopoteinases-2,-9proteins were detected by zymography. The stretch inducedmigrations of rMSCs were expropriated when the stretch stimulated activation ofMMP-2and MMP-9expression was inhibited by MMPs inhibitor GM6001. The resultsare as follows:①rMSCs primary separation, culture and identificationIn this study, percoll density gradient centrifugation combining with the adherentfeature of MSCs was used to sparate rMSCs. The sparated rMSCs are morphologicaluniform, spindle-shaped and swirling distribution. Flow cytometry results showed therMSCs primary cells express CD44and CD90but not CD34, which consistent with thecommon characteristics of MSCs.②Effect of mechanical tensile loading on rMSCs migration Cells were cultured on elastic silicone membrane, and a homemade cell tensileloading device was used to stretch the silicone membrane to apply loading on the cells.Transwell method was used to detect cell migration. The results showed that1Hz,10%strain,8h loading condition significantly affected the migration of rMSCs. Thescratching assay further confirmed the results of transwell method as well.③MMP-2and MMP-9involved in mechanical stretch-induced migration ofrMSCsThe expression of matrix metallopoteinases-2,-9proteins were detected byzymography under the condition of1Hz,10%strain and8h It was found that the in thetensile loading group, MMP-2and MMP-9activity delete in rMSCs were significantlyincreased to235%and248%of the control group. MMPs inhibitor GM6001was addedbefore mechanical stretch. Detection of cell migration and MMP-2and MMP-9expression suggested that25μM GM6001significantly inhibited the secretion ofMMP-2,-9induced by stretch and the migration of rMSCs stimulated by the cyclic wasexpropriated as well. The results suggested that:1Hz,10%strain and8h cyclic stretchpromoted the migration of rMSCs which may be achieved by stimulating the deleterMSCs secretion of MMP-2and MMP-9.The results of this study showed that the appropriate mechanical tensile loadingcan induce delete the rMSCs secretion of MMP-2and MMP-9, and through whichpromoted the ability of rMSC migration. Our study offers experimental evidences to invitro control of rMSC migration so that to better utilze them in tissue regeneration.Meanwhile, our results may be helpful to inspire new ideas and methods in the researchof stem cell therapy, tissue engineering, regeneration medicine and so on. |
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