Analysis of Alterations in Morphologic Characteristics of Mesenchymal Stem Cells by Mechanical Stimulation during Differentiation into Smooth Muscle Cells

Objective: mesenchymal stem cells (mscs) can be expanded and differentiated intomany mature cell types including smooth muscle cells (smcs). in addition to growth factor,cyclic stretch contributes to differentiation of stem cells. mechanical stimuli are criticalto morphological changes, development, regeneration, differentiation and pathology ofmesenchymal tissues. the aim of this study is to investigate effects of cyclic stretch withdiffering amplitudes on morphology and differentiation of mesenchymal stem cells.materials and methods: mesenchymal stem cells are extracted from human bone marrow.cells are cultured on silicone membrane and exposed to cyclic stretch by a custommade device. cellular images are captured before and after tests. effects of 5% and 15%uniaxial strain with 1hz frequency and 1-8 hour durations on morphology of human mesenchymalstem cells are investigated. it is assumed that environmental factors such asmechanical loading regulate mscs differentiation to smcs. fractal analysis is used toquantify alterations in cellular morphology. an image processing method with a designedcode is used for evaluation of fractal dimension parameter.results: results demonstrate statistically significant change in cell morphology due tomechanical stretch. by elevation of strain amplitude and number of load cycles, fractaldimensions of cell images decrease. such decrease is equivalent to alignment of cells bymechanical stimulus. cells are differentiated to smcs purely by cyclic stretch. the initiationand rate of differentiation depend on mechanical conditions.conclusion: to produce functional smcs for engineered tissues, mscs can be exposed to uniaxialcyclic stretch. the functionality of differentiated smcs depends on loading conditions.