Effects And Mechanisms Of MGF On The Migration Of Muscle Satellite Cells In Vitro

ObjectiveWhen the skeletal muscle damage occurs, in order to repair the injured skeletalmuscle，muscle satellite cells in the quiescent state are activated by growth factors andmigrate to the injury site, aiming to format the new myotubes through theproliferation and differentiation. Previous studies have mainly focused on the aspectof the proliferation and differentiation of muscle satellite cells, but studies of themigration of muscle satellite cells studies are rare, and the mechanisms of theirbiological functions are not completely clear yet. In this study, we will discuss theeffects of MGF on the migration of muscle satellite cells, and the mechanism of themigration signal transduction pathways in vitro by using K1030(PI3K/Akt inhibitor)and K1022(MAPK/MEK inhibitor).Materials and MethodsWe extracted hind limbs gastrocnemius, soleus and back muscle from SD rats (male,3-4weeks old) under sterile conditions, digested the muscle tissue（s） to releasemuscle satellite cells by0.1%collagenase (Type II) and25%trypsin in clean benches,and purified muscle satellite cells through twice differential adhesion. Then theviability rate and purity of muscle satellite cells were identified by trypan blue and-sarcometric actin respectively.(The) muscle satellite cells within five generationsselected in this study were divided into three groups: control group (group C), k1030group, and k1022group; treated by0ng/ml,25ng/ml,35ng/ml, and45ng/ml MGFrespectively. After a12-hour intervention, the cell migration rate was measured byTranswell assay and the inhibitors effects were detected by Western Bolt.Results1. Trypan blue staining results: Assessment of cell viability showed that the live SCproportion was95.6%.2. The immunocytochemistry of-sarcometric actin results: Cells were detected ina tan colored, were positive, showing they were muscle satellite cells.3. Transwell results:1) In the situation of25,35,45ng/ml MGF, the migration of muscle satellite cells wassignificantly higher than0ng/ml MGF in group C.2) In the same situation of MGF, the migration of muscle satellite cells in groupk1030was significantly lower than group C; the migration of muscle satellite cells ingroup k1022was lower than group C, but only in the25ng/ml MGF group was significant.4. Western Bolt results:1) In the situation of25,35,45ng/ml MGF, the expression of Akt and phosphorylationAkt was significantly higher than in0ng/ml MGF,but the phosphorylation rate waslower; the expression of Erk1/2and phosphorylation Erk1/2was was significantlyhigher than in0ng/ml,the the phosphorylation rate was higher simultaneously.2) The expression of Akt and phosphorylation Akt in group k1030was significantlylower than group C in the same situation of MGF, and in the case0f0,45ng/ml MGFthe phosphorylation rate was significantly lower; in the same situation of MGF,theexpression of Erk1/2and phosphorylation Erk1/2in group k1022was significantlylower than in group C, the phosphorylation rate was lower simultaneously.Conclusions1. Within0-45ng/ml, when the concentration of extrinsic MGF is higher, themigration of muscle satellite cells is more obvious.2. In terms of extrinsic MGF, the muscle satellite cell migration is mainly affected byPI3K/Akt signaling pathway, while possibly MAPK/MEK signaling pathway maybe also a functional factor.