ABSTRACT
BACKGROUND:Mechanical stimulation triggers a muscle tissue remodeling, during which, myoblast process is a multi-stage development process. Many signals in extracellular matrix are involved in myoblast process, and mechanical signals are considered as important external factors for muscle formation and regeneration. Numerous studies concerning cyclic tensile stress effects on myoblast proliferation and apoptosis have been reported, but the specific mechanism underlying the mechanical stimulation in muscle formation is stil unclear. OBJECTIVE:To study the effects of cyclic stretch on proliferation of C2C12 myoblasts and its mechanism. METHODS:C2C12 myoblasts were cultured in vitro under 10%cyclic stretch for 6, 12 and 24 hours. RESULTS AND CONCLUSION:The results of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that with the time of cyclic stretch, the proliferation of C2C12 myoblasts and the rate of S-phase fraction were gradual y increased and peaked at 12 hours (P<0.05), and then decreased. Western blot assay showed that the expression of nuclear transcription factorκB protein was decreased with time, which was inversely correlated to the proliferation of C2C12 myoblasts, but increased at 24 hours under the cyclic stretch. These findings indicate that the cyclic stretch can induce C2C12 myoblasts proliferation and alter the cellcycle. Nuclear transcription factorκB may be involved in this process.