Early Responses Of Bone Marrow Stem Cells To Different Mechanical Signals Through P38MAPK Signaling Pathway

Objective: This study was to examine early responses of p38 MAPK in rat bone marrow stem cells to mechanical stimuli of different strain and time.Methods:1. Expose bilateral femur and tibia of rat, extract bone marrow2. The primary MSCs were cultured with low-glucose DEME containing 10% FBS (fetal bovine serum) and antibiotics (penicillin G100 units/ml and streptomycin 100ug/ml) in CO2 incubator (37℃and 5% CO2). Digest cells with 0.25% Trypsin-EDTA then passage.3. Experimental group: response of p38 MAPK in rat MSCs to mechanical stimuli of 15 min of different strain ( 0μ, 1000μ, 2000μ, 3000μ, 4000μ, 5000μ, 6000μ); response of p38 MAPK in rat MSCs to mechanical stimuli of different times (0 min, 5 min, 15 min, 30 min, 60 min ).4. Applying mechanical stress: The plates of which rat MSCs grow at the surface were subjected to cyclic tensile or compressive strain by four-point bending system.5. Detection of p38 MAPK activation with the Western Blotting method: Protein were separated on 10% SDS-polyacrylamide gels followed by electrotransfer onto PVDF membranes. Incubate primary and secondary antibodies. Capture the photos of immunoreactive bands incubated by enhanced chemiluminescenece (ECL). Analyze the band intensity ratio.6. Statistical analysis: Statistic analysis was done by SPSS 13.0 software using one-way ANOVA, followed by multiple comparisons using the SNK TEST. A value of p<0.05 was statistical considered significant. Results: p38 MAPK could be activated by mechanical stimuli in 15 min most when rat MSCs were applied to both tensile and compressive strain. Conclusion: Rat MSCs were mechanical sensitive, p38 MAPK rat MSCs were mechanical sensitive kinase and participated in signal transfer of extracellular mechanic stimulus.